Top 10 tips for meteor-watchers

Gregor in Switzerland submitted this composite image from the morning of December 15.

Gregor in Switzerland submitted this composite image from the morning of December 15, 2015.

Your goal: to observe a meteor shower. You read an article about an upcoming meteor shower, and you want to see as many meteors as possible. You want to see the sky rain meteors like hailstones at an apocalyptic rate. You want exploding fireballs, peals of meteoric thunder, celestial mayhem. Well … that likely won’t happen. Meteor showers, for the most part, aren’t like a shower of rain, and a meteor rate of one a minute is a very, very good shower. Meteor showers are wonderful natural phenomena, a chance to commune with the outdoors and see something beautiful. How can you optimize your chances for seeing the most meteors? Follow the links below for EarthSky’s top 10 tips for meteor-watchers!

1. Be sure you know which days the shower will peak.

2. Find out the time of the shower’s peak in your time zone.

3. Watch on the nights around the peak, too.

4. Understanding the shower’s radiant point can help.

5. Find out the shower’s expected rate, or number of meteors per hour.

6. You must be aware of the phase of the moon.

7. Dress warmly.

8. Bring along that thermos of hot coffee or tea.

9. Bring a blanket or lawn chair.

10. Relax and enjoy the night sky.

Early Geminid meteor caught on the night of December 6, 2015, by Barry Simmons in Lake Martin, Alabama.

Early Geminid meteor caught on the night of December 6, 2015, by Barry Simmons in Lake Martin, Alabama.

1. Be sure you know which days the shower will peak. Meteor showers happen over many days, as Earth encounters a wide stream of icy particles in space: debris left behind by a comet. The peak is just what it implies. It’s a point in time when Earth is expected to encounter the greatest number of particles from a particular meteor stream. To find the peak dates, try EarthSky’s meteor guide for 2020. Be aware that most, but not all, meteor showers are best after midnight.

And here’s the catch …

The peak of the shower comes at the same time for all of us on Earth. Meanwhile, our clocks are saying different times. So …

2. Find out the time of the shower’s peak in your timezone. You don’t need to watch exactly at the peak time. But it can help you decide which night is absolutely best for you.

Different sources might list different times for the peak of a meteor shower. In that case, go with a source you trust. Here at EarthSky, we trust the Observer’s Handbook from the Royal Astronomical Society of Canada. Predictions are not always spot on, and the peak typically stretches over a day or so.

See how it works?

The time of the peak will nearly always be given in UTC. That stands for Coordinated Universal Time, and it’s the primary time standard by which the world regulates clocks and time. Learn to translate UTC to your time zone in this article.

3. Watch on the nights around the peak, too. If you miss a shower’s peak, you might not see as many meteors. But don’t let that discourage you! As we’ve mentioned before, predictions for meteor shower peaks are not always right on the money. It’s possible to see very nice meteor displays hours before or after the published peak.

For example, who can forget the famous 1998 Leonid meteor shower? The predicted peak favored observers in Europe, and yet those of us in the states were nevertheless treated to wonderful displays of Leonids on the nights before and after the predicted peak.

Just remember, meteor showers are part of nature. They often defy prediction.

The Geminid meteors radiate from near star Castor in Gemini.

The Geminid meteors radiate from near the star Castor in Gemini.

4. Understanding the shower’s radiant point can help. A meteor shower’s radiant point is that point in the sky from which the meteors will appear to radiate. Some people seem to think they have to be able to identify the radiant point in order to be able to watch the shower, but that is a serious misconception.

You can see meteors shoot up from the horizon before a shower’s radiant has even risen into the sky.

Here’s the power of the radiant point. Once it has risen into your sky, you’ll see more meteors. When it’s at its highest overhead – assuming you’re watching at a time when the shower has been producing meteors steadily over many hours – you’ll see the most meteors.

So find out the radiant point’s rising time. It can help you pinpoint the best time of night to watch the shower.

Randy Baumhover captured this image at Meyers Creek Beach on the Oregon coast.

Randy Baumhover captured this image at Meyers Creek Beach on the Oregon coast.

5. Find out the shower’s expected rate, or number of meteors per hour. Here we touch on a topic that often leads to some bad feelings, especially among novice meteor watchers. Tables of meteor showers almost always list what is known as the zenithal hourly rate (ZHR) for each shower.

The ZHR is the number of meteors you’ll see if you’re watching in a very dark sky, when the radiant overhead, when the shower is at its peak.

In other words, the ZHR represents the number of meteors you might see per hour given the very best observing conditions during the shower’s maximum.

Now let’s apply this term to a real world example. Let’s say the December Geminid meteor shower has a ZHR of 120 meteors per hour. That doesn’t mean you’ll see 120 meteors per hour, but it does mean you might if you’re watching on a peak night in a dark sky, when the radiant is highest.

If the peak occurs when it’s still daylight at your location, if most of the meteors are predominantly faint, if a bright moon is out , or if you’re located in a light-polluted area, the total number of meteors you see will be considerably reduced.

Also know that most meteor showers have bursts of activity, with lulls in between. That’s why you should plan to watch the shower, from a dark location, for at least an hour or more. Several hours per night for several nights will give you the best chance of seeing the best show.

And that brings us to one of the most important factors of all for meteor-watchers…

6. You must be aware of the phase of the moon. If the moon is at a quarter phase or greater, you’re going to miss meteors, even if your skies are otherwise dark. It’s okay if the moon sets before the radiant rises, because the Earth blocks the moon’s light from the sky. But nothing dampens the display of a meteor shower more effectively than the presence of a bright moon.

Now you’re almost ready. Just a few final tips.

7. Dress warmly. The nights can be cool or cold, even during the spring and summer months.

8. Bring along that thermos of hot coffee or tea. It’ll be your friend at 3 a.m.

9. Bring a blanket or lawn chair for reclining comfortably while looking up at the sky. If you’re observing with a friend, set your chairs out back to back, and look at different parts of the sky. Then when one of you sees a meteors, he or she can call out “meteor,” and everyone can turn and look.

10. Relax and enjoy the night sky. Not every meteor shower is a winner. Sometimes, you may come away from a shower seeing only one meteor. But consider this. If that one meteor is a bright one that takes a slow path across a starry night sky … it’ll be worth it.

To be really successful at observing any meteor shower, you need to get into a kind of Zen state, waiting and expecting the meteors to come to you if you place yourself in the position to see them. Or forget the Zen state, and let yourself be guided by this old meteor watcher’s motto:

You might see a lot or you might not see many, but if you stay in the house, you won’t see any.

By the way, if you’re interested in learning more about meteor showers, or want to contribute meteor counts and brightness estimations, contact the following organizations: The American Meteor Society and the International Meteor Organization. Both provided the latest predictions as well as information to guide you in serious meteor observing.

View larger. | Early Geminid fireball caught on December 2, 2015 at 10:34 p.m. from the Tucson, Arizona foothills. Photo by Eliot Herman.

View larger. | Early Geminid fireball caught on December 2, 2015 at 10:34 p.m. from the Tucson, Arizona foothills. Photo via Eliot Herman.

Bottom line: How to watch a meteor shower. Tips for beginners.

EarthSky’s meteor guide for 2020



from EarthSky https://ift.tt/2Ql6pY4
Gregor in Switzerland submitted this composite image from the morning of December 15.

Gregor in Switzerland submitted this composite image from the morning of December 15, 2015.

Your goal: to observe a meteor shower. You read an article about an upcoming meteor shower, and you want to see as many meteors as possible. You want to see the sky rain meteors like hailstones at an apocalyptic rate. You want exploding fireballs, peals of meteoric thunder, celestial mayhem. Well … that likely won’t happen. Meteor showers, for the most part, aren’t like a shower of rain, and a meteor rate of one a minute is a very, very good shower. Meteor showers are wonderful natural phenomena, a chance to commune with the outdoors and see something beautiful. How can you optimize your chances for seeing the most meteors? Follow the links below for EarthSky’s top 10 tips for meteor-watchers!

1. Be sure you know which days the shower will peak.

2. Find out the time of the shower’s peak in your time zone.

3. Watch on the nights around the peak, too.

4. Understanding the shower’s radiant point can help.

5. Find out the shower’s expected rate, or number of meteors per hour.

6. You must be aware of the phase of the moon.

7. Dress warmly.

8. Bring along that thermos of hot coffee or tea.

9. Bring a blanket or lawn chair.

10. Relax and enjoy the night sky.

Early Geminid meteor caught on the night of December 6, 2015, by Barry Simmons in Lake Martin, Alabama.

Early Geminid meteor caught on the night of December 6, 2015, by Barry Simmons in Lake Martin, Alabama.

1. Be sure you know which days the shower will peak. Meteor showers happen over many days, as Earth encounters a wide stream of icy particles in space: debris left behind by a comet. The peak is just what it implies. It’s a point in time when Earth is expected to encounter the greatest number of particles from a particular meteor stream. To find the peak dates, try EarthSky’s meteor guide for 2020. Be aware that most, but not all, meteor showers are best after midnight.

And here’s the catch …

The peak of the shower comes at the same time for all of us on Earth. Meanwhile, our clocks are saying different times. So …

2. Find out the time of the shower’s peak in your timezone. You don’t need to watch exactly at the peak time. But it can help you decide which night is absolutely best for you.

Different sources might list different times for the peak of a meteor shower. In that case, go with a source you trust. Here at EarthSky, we trust the Observer’s Handbook from the Royal Astronomical Society of Canada. Predictions are not always spot on, and the peak typically stretches over a day or so.

See how it works?

The time of the peak will nearly always be given in UTC. That stands for Coordinated Universal Time, and it’s the primary time standard by which the world regulates clocks and time. Learn to translate UTC to your time zone in this article.

3. Watch on the nights around the peak, too. If you miss a shower’s peak, you might not see as many meteors. But don’t let that discourage you! As we’ve mentioned before, predictions for meteor shower peaks are not always right on the money. It’s possible to see very nice meteor displays hours before or after the published peak.

For example, who can forget the famous 1998 Leonid meteor shower? The predicted peak favored observers in Europe, and yet those of us in the states were nevertheless treated to wonderful displays of Leonids on the nights before and after the predicted peak.

Just remember, meteor showers are part of nature. They often defy prediction.

The Geminid meteors radiate from near star Castor in Gemini.

The Geminid meteors radiate from near the star Castor in Gemini.

4. Understanding the shower’s radiant point can help. A meteor shower’s radiant point is that point in the sky from which the meteors will appear to radiate. Some people seem to think they have to be able to identify the radiant point in order to be able to watch the shower, but that is a serious misconception.

You can see meteors shoot up from the horizon before a shower’s radiant has even risen into the sky.

Here’s the power of the radiant point. Once it has risen into your sky, you’ll see more meteors. When it’s at its highest overhead – assuming you’re watching at a time when the shower has been producing meteors steadily over many hours – you’ll see the most meteors.

So find out the radiant point’s rising time. It can help you pinpoint the best time of night to watch the shower.

Randy Baumhover captured this image at Meyers Creek Beach on the Oregon coast.

Randy Baumhover captured this image at Meyers Creek Beach on the Oregon coast.

5. Find out the shower’s expected rate, or number of meteors per hour. Here we touch on a topic that often leads to some bad feelings, especially among novice meteor watchers. Tables of meteor showers almost always list what is known as the zenithal hourly rate (ZHR) for each shower.

The ZHR is the number of meteors you’ll see if you’re watching in a very dark sky, when the radiant overhead, when the shower is at its peak.

In other words, the ZHR represents the number of meteors you might see per hour given the very best observing conditions during the shower’s maximum.

Now let’s apply this term to a real world example. Let’s say the December Geminid meteor shower has a ZHR of 120 meteors per hour. That doesn’t mean you’ll see 120 meteors per hour, but it does mean you might if you’re watching on a peak night in a dark sky, when the radiant is highest.

If the peak occurs when it’s still daylight at your location, if most of the meteors are predominantly faint, if a bright moon is out , or if you’re located in a light-polluted area, the total number of meteors you see will be considerably reduced.

Also know that most meteor showers have bursts of activity, with lulls in between. That’s why you should plan to watch the shower, from a dark location, for at least an hour or more. Several hours per night for several nights will give you the best chance of seeing the best show.

And that brings us to one of the most important factors of all for meteor-watchers…

6. You must be aware of the phase of the moon. If the moon is at a quarter phase or greater, you’re going to miss meteors, even if your skies are otherwise dark. It’s okay if the moon sets before the radiant rises, because the Earth blocks the moon’s light from the sky. But nothing dampens the display of a meteor shower more effectively than the presence of a bright moon.

Now you’re almost ready. Just a few final tips.

7. Dress warmly. The nights can be cool or cold, even during the spring and summer months.

8. Bring along that thermos of hot coffee or tea. It’ll be your friend at 3 a.m.

9. Bring a blanket or lawn chair for reclining comfortably while looking up at the sky. If you’re observing with a friend, set your chairs out back to back, and look at different parts of the sky. Then when one of you sees a meteors, he or she can call out “meteor,” and everyone can turn and look.

10. Relax and enjoy the night sky. Not every meteor shower is a winner. Sometimes, you may come away from a shower seeing only one meteor. But consider this. If that one meteor is a bright one that takes a slow path across a starry night sky … it’ll be worth it.

To be really successful at observing any meteor shower, you need to get into a kind of Zen state, waiting and expecting the meteors to come to you if you place yourself in the position to see them. Or forget the Zen state, and let yourself be guided by this old meteor watcher’s motto:

You might see a lot or you might not see many, but if you stay in the house, you won’t see any.

By the way, if you’re interested in learning more about meteor showers, or want to contribute meteor counts and brightness estimations, contact the following organizations: The American Meteor Society and the International Meteor Organization. Both provided the latest predictions as well as information to guide you in serious meteor observing.

View larger. | Early Geminid fireball caught on December 2, 2015 at 10:34 p.m. from the Tucson, Arizona foothills. Photo by Eliot Herman.

View larger. | Early Geminid fireball caught on December 2, 2015 at 10:34 p.m. from the Tucson, Arizona foothills. Photo via Eliot Herman.

Bottom line: How to watch a meteor shower. Tips for beginners.

EarthSky’s meteor guide for 2020



from EarthSky https://ift.tt/2Ql6pY4

EarthSky’s 2020 meteor shower guide

Long thin white streak of meteor trail in dawn light bisecting bright dot.

What are the odds?! This amazing image is from Emma Zulaiha Zulkifli in Sabah, on the island of Borneo in Malaysia. She caught a bright meteor streaking right in front of the bright planet Venus on December 15, 2018. She wrote: “Yes, the meteor actually did streak in front of Venus! Only a bit of tweaking on contrast and noise reduction done in Photoshop CC2018.” Fuji X-A1, 18-55mm f2.8 with Tripod, Exif : iso2000, 30″, f2.8. Way to go, Emma!

January 4, 2020 Quadrantids

April 22, 2020 Lyrids

May 5, 2020 Eta Aquariids

Late July, 2020 Delta Aquariids

August 12, 2020 Perseids

October 7, 2020 Draconids

October 21, 2020 Orionids

November 4-5, 2020 South Taurids

November 11-12, 2020 North Taurids

November 17, 2020 Leonids

December 13-14, 2020 Geminids

December 22, 2020 Ursids

A word about moonlight

Most important: a dark sky

Know your dates and times

Where to go to watch a meteor shower

What to bring with you

Are the predictions reliable?

Remember …

Starry sky with many meteor trails radiating out from one point.

Quadrantid radiant composite via Scott MacNeill of Frosty Drew Observatory in Charleston, Rhode Island.

January 4, 2020, before dawn, the Quadrantids
The Quadrantids can produce over 100 meteors per hour, but the narrow peak of this shower lasts only a few hours and doesn’t always come at an opportune time. The radiant point is in the part of the sky that used to be considered the constellation Quadrans Muralis the Mural Quadrant. You’ll find this radiant near the famous Big Dipper asterism (chart here), in the north-northeastern sky after midnight and highest up before dawn. Because the radiant is fairly far to the north on the sky’s dome, meteor numbers tend to be greater at northerly latitudes in the Northern Hemisphere. In 2020, watch in the wee hours – after midnight and before dawn – on January 4. The moon is somewhat past first quarter phase, providing moon-free viewing in the predawn hours for 2020’s Quadrantid meteor shower.

Everything you need to know: Quadrantid meteor shower

Concentric circles of star trails with a meteor streaking across.

Lyrid meteor in 2014 by Simon Waldram in Fuerteventura in the Canary Islands. He discovered it as he finished batch editing 320 photos to make a startrail image.

April 22, 2020, before dawn, the Lyrids
The Lyrid meteor shower – April’s shooting stars – lasts from about April 16 to 25. About 10 to 15 meteors per hour can be expected around the shower’s peak, in a dark sky. The Lyrids are known for uncommon surges that can sometimes bring the rate up to 100 per hour. Those rare outbursts are not easy to predict, but they’re one of the reasons the tantalizing Lyrids are worth checking out. The radiant for this shower is near the bright star Vega in the constellation Lyra (chart here), which rises in the northeast at about 10 p.m. on April evenings. In 2020, we expect the peak viewing hours to take place in the dark hours before dawn April 22, with no moon to ruin the show.

Everything you need to know: Lyrid meteor shower

Long thin meteor trail crossing the Milky Way above trees and small house.

Long meteor caught during the peak of the May 2016 Eta Aquariid meteor shower, by Darla Young.

May 5, 2020, before dawn, the Eta Aquariids
This meteor shower has a relatively broad maximum; you can watch it the day before and after the predicted peak morning of May 5. Yet the nearly-full waxing gibbous moon is sure to dampen this year’s production. The shower favors the Southern Hemisphere and is often that hemisphere’s best meteor shower of the year. The radiant is near the star Eta in the constellation Aquarius the Water Bearer (click here for chart). The radiant comes over the eastern horizon at about 4 a.m. local time; that is the time at all locations across the globe. For that reason, you’ll want to watch this shower in the hour or two before dawn, no matter where you are on Earth. In the southern half of the U.S., 10 to 20 meteors per hour might be visible in a dark sky. Farther south – at latitudes in the Southern Hemisphere – you might see two to three times that number on a dark, moonless night. Meanwhile, at northerly latitudes – like those in the northern U.S. and Canada, or northern Europe – meteor numbers are lower for this shower. In 2020, the almost-full moon will be out nearly all night long, providing almost no dark sky for meteor watching. The most meteors will probably rain down in the predawn sky on May 5 – though in a moonlit sky! The broad peak to this shower means that some meteors may fly for a few days before and after the predicted optimal date.

Everything you need to know: Eta Aquariid meteor shower

Green fireball with glowing trail against the Milky Way.

Delta Aquariid in 2014, from David S. Brown in southwest Wyoming.

Late July 2020, before dawn, the Delta Aquariids
Like the Eta Aquariids in May, the Delta Aquariid meteor shower in July favors the Southern Hemisphere and tropical latitudes in the Northern Hemisphere. But these meteors can be seen from around the world. These faint meteors appear to radiate from near the star Skat or Delta in the constellation Aquarius the Water Bearer. The maximum hourly rate can reach 15 to 20 meteors in a dark sky. The nominal peak is around July 27-30, but, unlike many meteor showers, the Delta Aquariids lack a very definite peak. Instead, these medium-speed meteors ramble along fairly steadily throughout late July and early August. An hour or two before dawn usually presents the most favorable view of the Delta Aquariids. At the shower’s peak on or near July 28, 2020, the rather faint Delta Aquariid meteors will be best seen in the predawn hours, after the moon has set. You’ll still be seeing Eta Aquariids when the Perseids peak in August.

Everything you need to know: Delta Aquariid shower

Long meteor trail over a lake with brightly lit yellow pier.

The 2017 Perseid meteor shower peaked in moonlight, but that didn’t stop Hrvoje Crnjak in Šibenik, Croatia, from catching this bright Perseid on the morning of August 12, 2017. Notice the variations in brightness and color throughout, and the little “pop” of brightness toward the bottom. A brightness “pop” like that comes from a clump of vaporizing debris. Thank you, Hrvoje!

Late evening to dawn on August 11, 12 and 13, 2020, the Perseids
The Perseid meteor shower is perhaps the most beloved meteor shower of the year for the Northern Hemisphere. It’s a rich meteor shower, and it’s steady. These swift and bright meteors radiate from a point in the constellation Perseus the Hero. As with all meteor shower radiant points, you don’t need to know Perseus to watch the shower; instead, the meteors appear in all parts of the sky. These meteors frequently leave persistent trains. Perseid meteors tend to strengthen in number as late night deepens into midnight, and typically produce the most meteors in the wee hours before dawn. In 2020, the peak night of this shower will be somewhat marred by the last quarter moon, although the brighter Perseids will likely overcome the moonlit glare. Predicted peak in 2020: the night of August 11-12, but try the nights before and after, too, from late night until dawn.

All you need to Know: Perseid meteor shower

Several meteor trails over a desert landscape with tall cacti.

Draconids near Tucson, Arizona, in 2013, by our friend Sean Parker Photography.

October 7, 2020, nightfall and evening, the Draconids
The radiant point for the Draconid meteor shower almost coincides with the head of the constellation Draco the Dragon in the northern sky. That’s why the Draconids are best viewed from the Northern Hemisphere. The Draconid shower is a real oddity, in that the radiant point stands highest in the sky as darkness falls. That means that, unlike many meteor showers, more Draconids are likely to fly in the evening hours than in the morning hours after midnight. This shower is usually a sleeper, producing only a handful of languid meteors per hour in most years. But watch out if the Dragon awakes! In rare instances, fiery Draco has been known to spew forth many hundreds of meteors in a single hour. In 2020, watch the Draconid meteors at nightfall and early evening on October 7. Try the nights of October 6 and 8, too. Fortunately, the waning gibbous moon won’t rise till late evening, providing moon-free viewing for several hours after nightfall.

All you need to know: Draconids in 2019

Beautiful green aurora along horizon reflected in shallow water, with a meteor trail above it.

Orionid meteor with aurora in 2013, by Tommy Eliassen Photography in Norway.

October 21, 2020, before dawn, the Orionids
On a dark, moonless night, the Orionids exhibit a maximum of about 10 to 20 meteors per hour. More meteors tend to fly after midnight, and the Orionids are typically at their best in the wee hours before dawn. These fast-moving meteors occasionally leave persistent trains. The Orionids sometimes produce bright fireballs, which can overcome some moonlight in years when the moon intrudes. If you trace these meteors backward, they seem to come from the Club of the famous constellation Orion the Hunter. In 2020, the waxing crescent moon sets in the evening, providing moon-free viewing for rest of the night. With no moon to ruin the show, try watching the Orionids in the wee hours before dawn on October 21 and 22.

Everything you need to know: Orionid meteor shower

Big green Taurid fireball reflected on a lake.

In 2015, the Taurids put on a spectacular display of fireballs, which lasted many days. Photographer Jeff Dai captured this one over Yamdrok Lake in Tibet.

Late night November 4 until dawn November 5, 2020, the South Taurids
The meteoroid streams that feed the South (and North) Taurids are very spread out and diffuse. Thus the Taurids are extremely long-lasting (September 25 to November 25) but usually don’t offer more than about five meteors per hour. That is true even on their peak nights. The Taurids are, however, well known for having a high percentage of fireballs, or exceptionally bright meteors. Plus, the two Taurid showers – South and North – augment each other. In 2020, the expected peak night of the South Taurid shower happens when a waning gibbous moon lights up the sky almost all night long. Peak viewing is just after midnight, though under the glaring light of a bright waning gibbous moon. The South and North Taurid meteors continue to rain down throughout the following week, but with more interference from the waxing gibbous moon!

Late night November 11 until dawn November 12, 2020, the North Taurids
Like the South Taurids, the North Taurids meteor shower is long-lasting (October 12 – December 2) but modest, and the peak number is forecast at about five meteors per hour. The North and South Taurids combine to provide a nice sprinkling of meteors throughout October and November. Typically, you see the maximum numbers at around midnight, when Taurus the Bull is highest in the sky. Taurid meteors tend to be slow-moving, but sometimes very bright. In 2020, the slender waning crescent moon – rising in the wee hours before dawn – won’t seriously intrude on the peak night of November 11 (morning of November 12).

Meteor streak over low-lying hills with sea in foreground.

James Younger sent in this photo during the 2015 peak of the Leonid meteor shower. It’s a meteor over the San Juan Islands in the Pacific Northwest.

November 17, 2020, before dawn, the Leonids
Radiating from the constellation Leo the Lion, the famous Leonid meteor shower has produced some of the greatest meteor storms in history – at least one in living memory, 1966 – with rates as high as thousands of meteors per minute during a span of 15 minutes on the morning of November 17, 1966. Indeed, on that beautiful night in 1966, the meteors did, briefly, fall like rain. Some who witnessed the 1966 Leonid meteor storm said they felt as if they needed to grip the ground, so strong was the impression of Earth plowing along through space, fording the meteoroid stream. The meteors, after all, were all streaming from a single point in the sky – the radiant point – in this case in the constellation Leo the Lion. Leonid meteor storms sometimes recur in cycles of 33 to 34 years, but the Leonids around the turn of the century – while wonderful for many observers – did not match the shower of 1966. And, in most years, the Lion whimpers rather than roars, producing a maximum of perhaps 10-15 meteors per hour on a dark night. Like many meteor showers, the Leonids ordinarily pick up steam after midnight and display the greatest meteor numbers just before dawn, for all points on the globe. In 2020, the moon will display a waxing crescent phase, and set at early evening, to provide moon-free skies nearly all night long. The expected peak night is from late night November 16 till dawn November 17. The Leonids tend to produce the most meteors in the predawn hours, at which time the moon will be long gone.

Everything you need to know: Leonid meteor shower

Very bright meteor trail behind bare trees.

Cynthia Haithcock in Troy, North Carolina, caught this Geminid in 2015. Looks like a bright one!

December 13-14, 2020, mid-evening until dawn, Geminids
Radiating from near the bright stars Castor and Pollux in the constellation Gemini the Twins, the Geminid meteor shower is one of the finest meteors showers in the Northern Hemisphere (though still visible, at lower rates, in the Southern Hemisphere). The meteors are plentiful, rivaling the August Perseids. They are often bold, white and bright. On a dark night, you can often catch 50 or more meteors per hour. The greatest number of meteors fall in the wee hours after midnight, centered around 2 a.m. local time (the time on your clock no matter where you are on Earth), when the radiant point is highest in the sky. In 2020, the peak of the shower almost coincides with new moon, providing dark skies all night long. Watch the usually reliable and prolific Geminid meteor shower from mid-evening December 13 until dawn December 14, with absolutely no moonlight to ruin the show.

Everything you need to know: Geminid meteor shower

December 22, 2020, before dawn, the Ursids
Die-hard meteor watchers in the Northern Hemisphere watch for Ursid meteors about a week after the Geminids. This low-key meteor shower is active each year from about December 17 to 26. The Ursids usually peak around the December solstice, perhaps offering 5 to 10 meteors per hour during the predawn hours in a dark sky. This year, in 2020, the first quarter moon will set in the evening, providing dark skies at late night and the morning hours.

Ursid meteors peak around December solstice

A word about moonlight. In 2020, moonlight poses no problem for the April Lyrids, November Leonids and December Geminids. The moon won’t seriously interfere with the October Draconids, October Orionids or November North Taurids. Some moon-free viewing time accompanies the January Quadrantids and July Delta Aquariids in the predawn sky, and the August Perseids in the evening sky. On the other hand, a nearly full moon obstructs the May Eta Aquariids, while a bright waning gibbous moon obstructs the November South Taurids. Our almanac page provides links for access to the moonrise and moonset times in your sky.

Most important: a dark sky. Here’s the first thing – the main thing – you need to know to become as proficient as the experts at watching meteors. That is, to watch meteors, you need a dark sky. It’s possible to catch a meteor or two or even more from the suburbs. But, to experience a true meteor shower – where you might see several meteors each minute – avoid city lights. EarthSky’s Stargazing page shows dark locations worldwide.

Know your dates and times. You also need to be looking on the right date, at the right time of night. Meteor showers occur over a range of dates, because they stem from Earth’s own movement through space. As we orbit the sun, we cross “meteor streams.” These streams of icy particles in space come from comets moving in orbit around the sun. Comets are fragile, icy bodies that litter their orbits with debris. When this cometary debris enters our atmosphere, it vaporizes due to friction with the air. If moonlight or city lights don’t obscure the view, we on Earth see the falling, vaporizing particles as meteors.

Where to go to watch a meteor shower. You can comfortably watch meteors from many places, assuming you have a dark sky: a rural back yard or deck, the hood of your car, the side of a road. State parks and national parks are good bets, but be sure they have a wide open viewing area, like a field; you don’t want to be stuck in the midst of a forest on meteor night. An EarthSky friend, veteran meteor-watcher and astrophotographer Sergio Garcia Rill, also offers this specific advice:

… you might want to give it a try but don’t know where to go. Well, in planning my night photoshoots I use a variety of apps and web pages to know how dark the sky is in a certain location, the weather forecast, and how the night sky will look.

Some suggested apps and websites:

EarthSky’s Best Places to Stargaze
https://earthsky.org/stargazing

Find a Dark Sky Place, from the International Dark Sky Association
https://www.darksky.org/our-work/conservation/idsp/finder/

Heavens-Above: Satellite predictions customized to your location
https://www.heavens-above.com

Stellarium Online: Star maps customized to your location
https://stellarium-web.org

Accuweather’s astronomy blog
https://www.accuweather.com/en/weather-blogs/astronomy

Dark Site Finder, from astrophotographer Kevin Palmer
https://darksitefinder.com/map/

Blue Marble Navigator
https://blue-marble.de/nightlights/2019

What to bring with you. You don’t need special equipment to watch a meteor shower. If you want to bring along equipment to make yourself more comfortable, consider a blanket or reclining lawn chair, a thermos with a hot drink, binoculars for gazing at the stars. Be sure to dress warmly enough, even in spring or summer, especially in the hours before dawn. Binoculars are fun to have. You won’t need them for watching the meteor shower, but, especially if you have a dark sky, you might not be able to resist pointing them at the starry sky.

Are the predictions reliable? Although astronomers have tried to publish exact predictions in recent years, meteor showers remain notoriously unpredictable. Your best bet is to go outside at the times we suggest, and plan to spend at least an hour, if not a whole night, reclining comfortably while looking up at the sky. Also remember that meteor showers typically don’t just happen on one night. They span a range of dates. So the morning before or after a shower’s peak might be good, too.

Remember … meteor showers are like fishing. You go, you enjoy nature … and sometimes you catch something.

Peak dates are derived from data published in the Observer’s Handbook by the Royal Astronomical Society of Canada and Guy Ottewell’s Astronomical Calendar.

Meteor trail from two very bright stars against a starry sky.

This Geminid meteor is seen coming straight from its radiant point, which is near the two brightest stars in Gemini, Castor and Pollux. Photo taken on the night of December 12-13, 2012, by EarthSky Facebook friend Mike O’Neal in Oklahoma. He said the 2012 Geminid meteor shower was one of the best meteor shows he’s ever seen.

Bottom line: Look here for information about all the major meteor showers between now and the year’s end. There are some good ones!

Find a dark place to observe meteor showers from worldwide.

EarthSky’s top 10 tips for meteor-watchers

Enjoy knowing where to look in the night sky? Please donate to help EarthSky keep going.



from EarthSky https://ift.tt/2FdJAzd
Long thin white streak of meteor trail in dawn light bisecting bright dot.

What are the odds?! This amazing image is from Emma Zulaiha Zulkifli in Sabah, on the island of Borneo in Malaysia. She caught a bright meteor streaking right in front of the bright planet Venus on December 15, 2018. She wrote: “Yes, the meteor actually did streak in front of Venus! Only a bit of tweaking on contrast and noise reduction done in Photoshop CC2018.” Fuji X-A1, 18-55mm f2.8 with Tripod, Exif : iso2000, 30″, f2.8. Way to go, Emma!

January 4, 2020 Quadrantids

April 22, 2020 Lyrids

May 5, 2020 Eta Aquariids

Late July, 2020 Delta Aquariids

August 12, 2020 Perseids

October 7, 2020 Draconids

October 21, 2020 Orionids

November 4-5, 2020 South Taurids

November 11-12, 2020 North Taurids

November 17, 2020 Leonids

December 13-14, 2020 Geminids

December 22, 2020 Ursids

A word about moonlight

Most important: a dark sky

Know your dates and times

Where to go to watch a meteor shower

What to bring with you

Are the predictions reliable?

Remember …

Starry sky with many meteor trails radiating out from one point.

Quadrantid radiant composite via Scott MacNeill of Frosty Drew Observatory in Charleston, Rhode Island.

January 4, 2020, before dawn, the Quadrantids
The Quadrantids can produce over 100 meteors per hour, but the narrow peak of this shower lasts only a few hours and doesn’t always come at an opportune time. The radiant point is in the part of the sky that used to be considered the constellation Quadrans Muralis the Mural Quadrant. You’ll find this radiant near the famous Big Dipper asterism (chart here), in the north-northeastern sky after midnight and highest up before dawn. Because the radiant is fairly far to the north on the sky’s dome, meteor numbers tend to be greater at northerly latitudes in the Northern Hemisphere. In 2020, watch in the wee hours – after midnight and before dawn – on January 4. The moon is somewhat past first quarter phase, providing moon-free viewing in the predawn hours for 2020’s Quadrantid meteor shower.

Everything you need to know: Quadrantid meteor shower

Concentric circles of star trails with a meteor streaking across.

Lyrid meteor in 2014 by Simon Waldram in Fuerteventura in the Canary Islands. He discovered it as he finished batch editing 320 photos to make a startrail image.

April 22, 2020, before dawn, the Lyrids
The Lyrid meteor shower – April’s shooting stars – lasts from about April 16 to 25. About 10 to 15 meteors per hour can be expected around the shower’s peak, in a dark sky. The Lyrids are known for uncommon surges that can sometimes bring the rate up to 100 per hour. Those rare outbursts are not easy to predict, but they’re one of the reasons the tantalizing Lyrids are worth checking out. The radiant for this shower is near the bright star Vega in the constellation Lyra (chart here), which rises in the northeast at about 10 p.m. on April evenings. In 2020, we expect the peak viewing hours to take place in the dark hours before dawn April 22, with no moon to ruin the show.

Everything you need to know: Lyrid meteor shower

Long thin meteor trail crossing the Milky Way above trees and small house.

Long meteor caught during the peak of the May 2016 Eta Aquariid meteor shower, by Darla Young.

May 5, 2020, before dawn, the Eta Aquariids
This meteor shower has a relatively broad maximum; you can watch it the day before and after the predicted peak morning of May 5. Yet the nearly-full waxing gibbous moon is sure to dampen this year’s production. The shower favors the Southern Hemisphere and is often that hemisphere’s best meteor shower of the year. The radiant is near the star Eta in the constellation Aquarius the Water Bearer (click here for chart). The radiant comes over the eastern horizon at about 4 a.m. local time; that is the time at all locations across the globe. For that reason, you’ll want to watch this shower in the hour or two before dawn, no matter where you are on Earth. In the southern half of the U.S., 10 to 20 meteors per hour might be visible in a dark sky. Farther south – at latitudes in the Southern Hemisphere – you might see two to three times that number on a dark, moonless night. Meanwhile, at northerly latitudes – like those in the northern U.S. and Canada, or northern Europe – meteor numbers are lower for this shower. In 2020, the almost-full moon will be out nearly all night long, providing almost no dark sky for meteor watching. The most meteors will probably rain down in the predawn sky on May 5 – though in a moonlit sky! The broad peak to this shower means that some meteors may fly for a few days before and after the predicted optimal date.

Everything you need to know: Eta Aquariid meteor shower

Green fireball with glowing trail against the Milky Way.

Delta Aquariid in 2014, from David S. Brown in southwest Wyoming.

Late July 2020, before dawn, the Delta Aquariids
Like the Eta Aquariids in May, the Delta Aquariid meteor shower in July favors the Southern Hemisphere and tropical latitudes in the Northern Hemisphere. But these meteors can be seen from around the world. These faint meteors appear to radiate from near the star Skat or Delta in the constellation Aquarius the Water Bearer. The maximum hourly rate can reach 15 to 20 meteors in a dark sky. The nominal peak is around July 27-30, but, unlike many meteor showers, the Delta Aquariids lack a very definite peak. Instead, these medium-speed meteors ramble along fairly steadily throughout late July and early August. An hour or two before dawn usually presents the most favorable view of the Delta Aquariids. At the shower’s peak on or near July 28, 2020, the rather faint Delta Aquariid meteors will be best seen in the predawn hours, after the moon has set. You’ll still be seeing Eta Aquariids when the Perseids peak in August.

Everything you need to know: Delta Aquariid shower

Long meteor trail over a lake with brightly lit yellow pier.

The 2017 Perseid meteor shower peaked in moonlight, but that didn’t stop Hrvoje Crnjak in Šibenik, Croatia, from catching this bright Perseid on the morning of August 12, 2017. Notice the variations in brightness and color throughout, and the little “pop” of brightness toward the bottom. A brightness “pop” like that comes from a clump of vaporizing debris. Thank you, Hrvoje!

Late evening to dawn on August 11, 12 and 13, 2020, the Perseids
The Perseid meteor shower is perhaps the most beloved meteor shower of the year for the Northern Hemisphere. It’s a rich meteor shower, and it’s steady. These swift and bright meteors radiate from a point in the constellation Perseus the Hero. As with all meteor shower radiant points, you don’t need to know Perseus to watch the shower; instead, the meteors appear in all parts of the sky. These meteors frequently leave persistent trains. Perseid meteors tend to strengthen in number as late night deepens into midnight, and typically produce the most meteors in the wee hours before dawn. In 2020, the peak night of this shower will be somewhat marred by the last quarter moon, although the brighter Perseids will likely overcome the moonlit glare. Predicted peak in 2020: the night of August 11-12, but try the nights before and after, too, from late night until dawn.

All you need to Know: Perseid meteor shower

Several meteor trails over a desert landscape with tall cacti.

Draconids near Tucson, Arizona, in 2013, by our friend Sean Parker Photography.

October 7, 2020, nightfall and evening, the Draconids
The radiant point for the Draconid meteor shower almost coincides with the head of the constellation Draco the Dragon in the northern sky. That’s why the Draconids are best viewed from the Northern Hemisphere. The Draconid shower is a real oddity, in that the radiant point stands highest in the sky as darkness falls. That means that, unlike many meteor showers, more Draconids are likely to fly in the evening hours than in the morning hours after midnight. This shower is usually a sleeper, producing only a handful of languid meteors per hour in most years. But watch out if the Dragon awakes! In rare instances, fiery Draco has been known to spew forth many hundreds of meteors in a single hour. In 2020, watch the Draconid meteors at nightfall and early evening on October 7. Try the nights of October 6 and 8, too. Fortunately, the waning gibbous moon won’t rise till late evening, providing moon-free viewing for several hours after nightfall.

All you need to know: Draconids in 2019

Beautiful green aurora along horizon reflected in shallow water, with a meteor trail above it.

Orionid meteor with aurora in 2013, by Tommy Eliassen Photography in Norway.

October 21, 2020, before dawn, the Orionids
On a dark, moonless night, the Orionids exhibit a maximum of about 10 to 20 meteors per hour. More meteors tend to fly after midnight, and the Orionids are typically at their best in the wee hours before dawn. These fast-moving meteors occasionally leave persistent trains. The Orionids sometimes produce bright fireballs, which can overcome some moonlight in years when the moon intrudes. If you trace these meteors backward, they seem to come from the Club of the famous constellation Orion the Hunter. In 2020, the waxing crescent moon sets in the evening, providing moon-free viewing for rest of the night. With no moon to ruin the show, try watching the Orionids in the wee hours before dawn on October 21 and 22.

Everything you need to know: Orionid meteor shower

Big green Taurid fireball reflected on a lake.

In 2015, the Taurids put on a spectacular display of fireballs, which lasted many days. Photographer Jeff Dai captured this one over Yamdrok Lake in Tibet.

Late night November 4 until dawn November 5, 2020, the South Taurids
The meteoroid streams that feed the South (and North) Taurids are very spread out and diffuse. Thus the Taurids are extremely long-lasting (September 25 to November 25) but usually don’t offer more than about five meteors per hour. That is true even on their peak nights. The Taurids are, however, well known for having a high percentage of fireballs, or exceptionally bright meteors. Plus, the two Taurid showers – South and North – augment each other. In 2020, the expected peak night of the South Taurid shower happens when a waning gibbous moon lights up the sky almost all night long. Peak viewing is just after midnight, though under the glaring light of a bright waning gibbous moon. The South and North Taurid meteors continue to rain down throughout the following week, but with more interference from the waxing gibbous moon!

Late night November 11 until dawn November 12, 2020, the North Taurids
Like the South Taurids, the North Taurids meteor shower is long-lasting (October 12 – December 2) but modest, and the peak number is forecast at about five meteors per hour. The North and South Taurids combine to provide a nice sprinkling of meteors throughout October and November. Typically, you see the maximum numbers at around midnight, when Taurus the Bull is highest in the sky. Taurid meteors tend to be slow-moving, but sometimes very bright. In 2020, the slender waning crescent moon – rising in the wee hours before dawn – won’t seriously intrude on the peak night of November 11 (morning of November 12).

Meteor streak over low-lying hills with sea in foreground.

James Younger sent in this photo during the 2015 peak of the Leonid meteor shower. It’s a meteor over the San Juan Islands in the Pacific Northwest.

November 17, 2020, before dawn, the Leonids
Radiating from the constellation Leo the Lion, the famous Leonid meteor shower has produced some of the greatest meteor storms in history – at least one in living memory, 1966 – with rates as high as thousands of meteors per minute during a span of 15 minutes on the morning of November 17, 1966. Indeed, on that beautiful night in 1966, the meteors did, briefly, fall like rain. Some who witnessed the 1966 Leonid meteor storm said they felt as if they needed to grip the ground, so strong was the impression of Earth plowing along through space, fording the meteoroid stream. The meteors, after all, were all streaming from a single point in the sky – the radiant point – in this case in the constellation Leo the Lion. Leonid meteor storms sometimes recur in cycles of 33 to 34 years, but the Leonids around the turn of the century – while wonderful for many observers – did not match the shower of 1966. And, in most years, the Lion whimpers rather than roars, producing a maximum of perhaps 10-15 meteors per hour on a dark night. Like many meteor showers, the Leonids ordinarily pick up steam after midnight and display the greatest meteor numbers just before dawn, for all points on the globe. In 2020, the moon will display a waxing crescent phase, and set at early evening, to provide moon-free skies nearly all night long. The expected peak night is from late night November 16 till dawn November 17. The Leonids tend to produce the most meteors in the predawn hours, at which time the moon will be long gone.

Everything you need to know: Leonid meteor shower

Very bright meteor trail behind bare trees.

Cynthia Haithcock in Troy, North Carolina, caught this Geminid in 2015. Looks like a bright one!

December 13-14, 2020, mid-evening until dawn, Geminids
Radiating from near the bright stars Castor and Pollux in the constellation Gemini the Twins, the Geminid meteor shower is one of the finest meteors showers in the Northern Hemisphere (though still visible, at lower rates, in the Southern Hemisphere). The meteors are plentiful, rivaling the August Perseids. They are often bold, white and bright. On a dark night, you can often catch 50 or more meteors per hour. The greatest number of meteors fall in the wee hours after midnight, centered around 2 a.m. local time (the time on your clock no matter where you are on Earth), when the radiant point is highest in the sky. In 2020, the peak of the shower almost coincides with new moon, providing dark skies all night long. Watch the usually reliable and prolific Geminid meteor shower from mid-evening December 13 until dawn December 14, with absolutely no moonlight to ruin the show.

Everything you need to know: Geminid meteor shower

December 22, 2020, before dawn, the Ursids
Die-hard meteor watchers in the Northern Hemisphere watch for Ursid meteors about a week after the Geminids. This low-key meteor shower is active each year from about December 17 to 26. The Ursids usually peak around the December solstice, perhaps offering 5 to 10 meteors per hour during the predawn hours in a dark sky. This year, in 2020, the first quarter moon will set in the evening, providing dark skies at late night and the morning hours.

Ursid meteors peak around December solstice

A word about moonlight. In 2020, moonlight poses no problem for the April Lyrids, November Leonids and December Geminids. The moon won’t seriously interfere with the October Draconids, October Orionids or November North Taurids. Some moon-free viewing time accompanies the January Quadrantids and July Delta Aquariids in the predawn sky, and the August Perseids in the evening sky. On the other hand, a nearly full moon obstructs the May Eta Aquariids, while a bright waning gibbous moon obstructs the November South Taurids. Our almanac page provides links for access to the moonrise and moonset times in your sky.

Most important: a dark sky. Here’s the first thing – the main thing – you need to know to become as proficient as the experts at watching meteors. That is, to watch meteors, you need a dark sky. It’s possible to catch a meteor or two or even more from the suburbs. But, to experience a true meteor shower – where you might see several meteors each minute – avoid city lights. EarthSky’s Stargazing page shows dark locations worldwide.

Know your dates and times. You also need to be looking on the right date, at the right time of night. Meteor showers occur over a range of dates, because they stem from Earth’s own movement through space. As we orbit the sun, we cross “meteor streams.” These streams of icy particles in space come from comets moving in orbit around the sun. Comets are fragile, icy bodies that litter their orbits with debris. When this cometary debris enters our atmosphere, it vaporizes due to friction with the air. If moonlight or city lights don’t obscure the view, we on Earth see the falling, vaporizing particles as meteors.

Where to go to watch a meteor shower. You can comfortably watch meteors from many places, assuming you have a dark sky: a rural back yard or deck, the hood of your car, the side of a road. State parks and national parks are good bets, but be sure they have a wide open viewing area, like a field; you don’t want to be stuck in the midst of a forest on meteor night. An EarthSky friend, veteran meteor-watcher and astrophotographer Sergio Garcia Rill, also offers this specific advice:

… you might want to give it a try but don’t know where to go. Well, in planning my night photoshoots I use a variety of apps and web pages to know how dark the sky is in a certain location, the weather forecast, and how the night sky will look.

Some suggested apps and websites:

EarthSky’s Best Places to Stargaze
https://earthsky.org/stargazing

Find a Dark Sky Place, from the International Dark Sky Association
https://www.darksky.org/our-work/conservation/idsp/finder/

Heavens-Above: Satellite predictions customized to your location
https://www.heavens-above.com

Stellarium Online: Star maps customized to your location
https://stellarium-web.org

Accuweather’s astronomy blog
https://www.accuweather.com/en/weather-blogs/astronomy

Dark Site Finder, from astrophotographer Kevin Palmer
https://darksitefinder.com/map/

Blue Marble Navigator
https://blue-marble.de/nightlights/2019

What to bring with you. You don’t need special equipment to watch a meteor shower. If you want to bring along equipment to make yourself more comfortable, consider a blanket or reclining lawn chair, a thermos with a hot drink, binoculars for gazing at the stars. Be sure to dress warmly enough, even in spring or summer, especially in the hours before dawn. Binoculars are fun to have. You won’t need them for watching the meteor shower, but, especially if you have a dark sky, you might not be able to resist pointing them at the starry sky.

Are the predictions reliable? Although astronomers have tried to publish exact predictions in recent years, meteor showers remain notoriously unpredictable. Your best bet is to go outside at the times we suggest, and plan to spend at least an hour, if not a whole night, reclining comfortably while looking up at the sky. Also remember that meteor showers typically don’t just happen on one night. They span a range of dates. So the morning before or after a shower’s peak might be good, too.

Remember … meteor showers are like fishing. You go, you enjoy nature … and sometimes you catch something.

Peak dates are derived from data published in the Observer’s Handbook by the Royal Astronomical Society of Canada and Guy Ottewell’s Astronomical Calendar.

Meteor trail from two very bright stars against a starry sky.

This Geminid meteor is seen coming straight from its radiant point, which is near the two brightest stars in Gemini, Castor and Pollux. Photo taken on the night of December 12-13, 2012, by EarthSky Facebook friend Mike O’Neal in Oklahoma. He said the 2012 Geminid meteor shower was one of the best meteor shows he’s ever seen.

Bottom line: Look here for information about all the major meteor showers between now and the year’s end. There are some good ones!

Find a dark place to observe meteor showers from worldwide.

EarthSky’s top 10 tips for meteor-watchers

Enjoy knowing where to look in the night sky? Please donate to help EarthSky keep going.



from EarthSky https://ift.tt/2FdJAzd

Polar stratospheric clouds over Sweden

Bright clouds in the night sky, reflecting in water along a shoreline.

View larger. | Göran Strand captured this glorious shot of polar stratospheric clouds on December 30, 2019 from Frösön, Sweden. He told EarthSky that these clouds: “… even lit up the surrounding landscape.”

As 2019 came to a close, northern Europe saw a beautiful display of polar stratospheric clouds. They are high-altitude clouds, seen at heights between 49,000 and 82,000 feet (15,000–25,000 meters). The sort made of frozen ice crystal are also called nacreous clouds or mother-of-pearl clouds. In describ ing them, Les Cowley at Atmospheric Optics said they are:

… rare, but once seen are never forgotten. They are mostly visible within two hours after sunset or before dawn when they blaze unbelievably bright with vivid and slowly shifting iridescent colours.

According to Tony Phillips at Spaceweather:

Polar stratospheric clouds are newsworthy because normally the stratosphere has no clouds at all. The stratosphere is arid and almost always transparent. Only when the temperature drops to a staggeringly cold -85C can sparse water molecules assemble themselves into icy stratospheric clouds.

PSCs are far more rare than auroras.

We received several photos of polar stratospheric clouds this week, and more appear in Spaceweather.com’s gallery. The image above – and video below – from Göran Strand in Sweden are among the best we saw. Thank you, Göran!

Bottom line: As 2019 ended, northerly latitudes saw a beautiful display of polar stratospheric clouds.

Read about polar stratospheric clouds at Atmospheric Optics



from EarthSky https://ift.tt/2Qha5tG
Bright clouds in the night sky, reflecting in water along a shoreline.

View larger. | Göran Strand captured this glorious shot of polar stratospheric clouds on December 30, 2019 from Frösön, Sweden. He told EarthSky that these clouds: “… even lit up the surrounding landscape.”

As 2019 came to a close, northern Europe saw a beautiful display of polar stratospheric clouds. They are high-altitude clouds, seen at heights between 49,000 and 82,000 feet (15,000–25,000 meters). The sort made of frozen ice crystal are also called nacreous clouds or mother-of-pearl clouds. In describ ing them, Les Cowley at Atmospheric Optics said they are:

… rare, but once seen are never forgotten. They are mostly visible within two hours after sunset or before dawn when they blaze unbelievably bright with vivid and slowly shifting iridescent colours.

According to Tony Phillips at Spaceweather:

Polar stratospheric clouds are newsworthy because normally the stratosphere has no clouds at all. The stratosphere is arid and almost always transparent. Only when the temperature drops to a staggeringly cold -85C can sparse water molecules assemble themselves into icy stratospheric clouds.

PSCs are far more rare than auroras.

We received several photos of polar stratospheric clouds this week, and more appear in Spaceweather.com’s gallery. The image above – and video below – from Göran Strand in Sweden are among the best we saw. Thank you, Göran!

Bottom line: As 2019 ended, northerly latitudes saw a beautiful display of polar stratospheric clouds.

Read about polar stratospheric clouds at Atmospheric Optics



from EarthSky https://ift.tt/2Qha5tG

Close and far moons in 2020

side-by-side photos of the full moon, with the one on the left considerably larger than the one on the right.

Here’s a comparison between the December 3, 2017, full moon at perigee (closest to Earth for the month) and 2017’s farthest full moon in June at apogee (farthest from Earth for the month) by Muzamir Mazlan at Telok Kemang Observatory, Port Dickson, Malaysia.

The moon’s distance from Earth varies throughout its monthly orbit because the moon’s orbit isn’t perfectly circular. Every month, the moon’s eccentric orbit carries it to apogee – its most distant point from Earth – and then, some two weeks later, to perigee – the moon’s closest point to Earth in its monthly orbit.

EarthSky lunar calendars are cool! They make great gifts. Order now. Going fast!

In this post, beneath the illustration below, we list the year’s 14 apogees and 13 perigees. Yes, the moon’s apparent size in our sky does change across this cycle of the moon. The variation in the moon’s apparent size is akin to that of a U.S. quarter versus a U.S. nickel.

Also in this post, we share with you a little-known fact about the intriguing cycle of close and far moons.

This year’s farthest apogee comes on March 24, 2020 (252,707 miles or 406,692 km), and the closest perigee occurs some 2 weeks later, on April 7 (221,772 miles or 356,907 km). That’s a difference of about 30,000 miles (50,000 km). Meanwhile, the moon’s mean distance (semi-major axis) from Earth is 238,855 miles (384,400 km).

Perfect circle around Earth, overlapped by slightly eccentric dotted line indicating orbit of moon.

The moon’s orbit around Earth isn’t a circle, but it’s very nearly circular, as the above diagram shows. Diagram by Brian Koberlein. Used with permission.

Lunar apogees and perigees in 2020

Apogee Perigee
Jan 02 Jan 13
Jan 29 Feb 10
Feb 26 Mar 10
Mar 24 Apr 07
Apr 20 May 06
May 18 June 03
June 15 June 30
July 12 July 25
Aug 09 Aug 21
Sept 06 Sept 18
Oct 03 Oct 16
Oct 30 Nov 14
Nov 27 Dec 12
Dec 24

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Amazingly, in periods of four years, lunar apogees and perigees fall on the same, or nearly the same calendar dates. Let’s look four years ahead, to the year 2024:

Lunar apogees and perigees in 2024

Apogee Perigee
Jan 01 Jan 13
Jan 29 Feb 10
Feb 25 Mar 10
Mar 23 Apr 07
Apr 20 May 05
May 17 June 02
June 14 June 27
July 12 July 24
Aug 09 Aug 21
Sept 05 Sept 18
Oct 02 Oct 17
Oct 29 Nov 14
Nov 26 Dec 12
Dec 24

Also, in cycles of two years, the calendar dates remain the same, or nearly so, except that the lunar apogees and perigees trade places. For instance, let’s look two years beyond 2020, to the year 2022:

Lunar perigees and apogees in 2022

Perigee Apogee
Jan 01 Jan 14
Jan 30 Feb 11
Feb 26 Mar 10
Mar 23 Apr 07
Apr 19 May 05
May 17 June 02
June 14 June 29
July 13 July 26
Aug 10 Aug 22
Sept 07 Sept 19
Oct 04 Oct 17
Oct 29 Nov 14
Nov 26 Dec 12
Dec 24

Want to know more? Here’s for a complete listing of all lunar perigees and apogees for the 21st century (2001 to 2100) and a perigee and apogee calculator.

Here’s a little-known fact of the moon’s apogee/perigee cycle, among both professional astronomers and lay people. That is, the cycle causes lunar apogees and perigees to align on the same, or nearly the same, calendar dates every four years. That’s because 53 returns to perigee (or apogee) are nearly commensurate with four calendar years.

The mean length of the anomalistic month (perigee to perigee, or apogee to apogee) is 27.55455 days, whereas the average Gregorian year equals 365.2425 days. Hence:

27.55455 x 53 = 1460.3912 days

365.2425 x 4 = 1460.97 days

Small full moon alternating with large crescent moon.

This animation by Peter Lowenstein in Zimbabwe contrasts the size of the May 27, 2017, waxing crescent moon, which was close to Earth, with the June 9, 2017, full moon, which was far from Earth. Read more about this image.

Bottom line: In periods of four years, lunar apogees and perigees fall on the same, or nearly the same, calendar dates.



from EarthSky https://ift.tt/2QlfXCt
side-by-side photos of the full moon, with the one on the left considerably larger than the one on the right.

Here’s a comparison between the December 3, 2017, full moon at perigee (closest to Earth for the month) and 2017’s farthest full moon in June at apogee (farthest from Earth for the month) by Muzamir Mazlan at Telok Kemang Observatory, Port Dickson, Malaysia.

The moon’s distance from Earth varies throughout its monthly orbit because the moon’s orbit isn’t perfectly circular. Every month, the moon’s eccentric orbit carries it to apogee – its most distant point from Earth – and then, some two weeks later, to perigee – the moon’s closest point to Earth in its monthly orbit.

EarthSky lunar calendars are cool! They make great gifts. Order now. Going fast!

In this post, beneath the illustration below, we list the year’s 14 apogees and 13 perigees. Yes, the moon’s apparent size in our sky does change across this cycle of the moon. The variation in the moon’s apparent size is akin to that of a U.S. quarter versus a U.S. nickel.

Also in this post, we share with you a little-known fact about the intriguing cycle of close and far moons.

This year’s farthest apogee comes on March 24, 2020 (252,707 miles or 406,692 km), and the closest perigee occurs some 2 weeks later, on April 7 (221,772 miles or 356,907 km). That’s a difference of about 30,000 miles (50,000 km). Meanwhile, the moon’s mean distance (semi-major axis) from Earth is 238,855 miles (384,400 km).

Perfect circle around Earth, overlapped by slightly eccentric dotted line indicating orbit of moon.

The moon’s orbit around Earth isn’t a circle, but it’s very nearly circular, as the above diagram shows. Diagram by Brian Koberlein. Used with permission.

Lunar apogees and perigees in 2020

Apogee Perigee
Jan 02 Jan 13
Jan 29 Feb 10
Feb 26 Mar 10
Mar 24 Apr 07
Apr 20 May 06
May 18 June 03
June 15 June 30
July 12 July 25
Aug 09 Aug 21
Sept 06 Sept 18
Oct 03 Oct 16
Oct 30 Nov 14
Nov 27 Dec 12
Dec 24

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Amazingly, in periods of four years, lunar apogees and perigees fall on the same, or nearly the same calendar dates. Let’s look four years ahead, to the year 2024:

Lunar apogees and perigees in 2024

Apogee Perigee
Jan 01 Jan 13
Jan 29 Feb 10
Feb 25 Mar 10
Mar 23 Apr 07
Apr 20 May 05
May 17 June 02
June 14 June 27
July 12 July 24
Aug 09 Aug 21
Sept 05 Sept 18
Oct 02 Oct 17
Oct 29 Nov 14
Nov 26 Dec 12
Dec 24

Also, in cycles of two years, the calendar dates remain the same, or nearly so, except that the lunar apogees and perigees trade places. For instance, let’s look two years beyond 2020, to the year 2022:

Lunar perigees and apogees in 2022

Perigee Apogee
Jan 01 Jan 14
Jan 30 Feb 11
Feb 26 Mar 10
Mar 23 Apr 07
Apr 19 May 05
May 17 June 02
June 14 June 29
July 13 July 26
Aug 10 Aug 22
Sept 07 Sept 19
Oct 04 Oct 17
Oct 29 Nov 14
Nov 26 Dec 12
Dec 24

Want to know more? Here’s for a complete listing of all lunar perigees and apogees for the 21st century (2001 to 2100) and a perigee and apogee calculator.

Here’s a little-known fact of the moon’s apogee/perigee cycle, among both professional astronomers and lay people. That is, the cycle causes lunar apogees and perigees to align on the same, or nearly the same, calendar dates every four years. That’s because 53 returns to perigee (or apogee) are nearly commensurate with four calendar years.

The mean length of the anomalistic month (perigee to perigee, or apogee to apogee) is 27.55455 days, whereas the average Gregorian year equals 365.2425 days. Hence:

27.55455 x 53 = 1460.3912 days

365.2425 x 4 = 1460.97 days

Small full moon alternating with large crescent moon.

This animation by Peter Lowenstein in Zimbabwe contrasts the size of the May 27, 2017, waxing crescent moon, which was close to Earth, with the June 9, 2017, full moon, which was far from Earth. Read more about this image.

Bottom line: In periods of four years, lunar apogees and perigees fall on the same, or nearly the same, calendar dates.



from EarthSky https://ift.tt/2QlfXCt

Sun’s entry into zodiac signs, 2020

Astrological chart via Wikipedia

An astrological chart, via Wikipedia. Want to see the difference between the sun’s location according to astrology, and the sun’s location according to astronomy? Bookmark this article and then click here for dates of sun’s entry into each constellation of the zodiac.

Astronomy and astrology are different. One difference … astrological signs of the tropical zodiac remain fixed relative to seasonal markers, such as the equinox and solstice points on the sky’s dome. Meanwhile, the constellations of the zodiac (and signs of the sidereal zodiac) slowly but surely shift eastward relative to the equinox and solstice points, over the long course of time, due to a motion of Earth called precession.

Moon lovers! Order this year’s EarthSky lunar calendar here

Also, signs of both the tropical and sidereal zodiac represent equal 30 degree divisions whereas the constellations of the zodiac vary in size.

In a celestial coordinate system commonly used by astronomers and astrologers, the sun resides at the First Point of Aries on the March equinox (0 degrees of longitude on the ecliptic), regardless of the fact that the sun shines in front of the constellation Pisces on the March equinox in our day and age.

Twelve cryptic symbols.

Symbols for the signs of the Zodiac. Both astrologers and astronomers sometimes use these symbols. Image via Wikipedia.

We provide the dates for the sun’s entry into each sign of the tropical zodiac (and corresponding ecliptic longitude) for the year 2020.

Dec 22, 2019: Sun enters sign Capricorn (270 degrees)

Jan 20, 2020: Sun enters sign Aquarius (300 degrees)

Feb 19, 2020: Sun enters sign Pisces (330 degrees)

Mar 20, 2020: Sun enters sign Aries (0 degrees)

April 19, 2020: Sun enters sign Taurus (30 degrees)

May 20, 2020: Sun enters sign Gemini (60 degrees)

June 20, 2020: Sun enters sign Cancer (90 degrees)

July 22, 2020: Sun enters sign Leo (120 degrees)

Aug 22, 2020: Sun enters sign Virgo (150 degrees)

Sep 22, 2020: Sun enters sign Libra (180 degrees)

Oct 22, 2020: Sun enters sign Scorpio (210 degrees)

Nov 21, 2020: Sun enters sign Sagittarius (240 degrees)

Dec 21, 2020: Sun enters sign Capricorn (270 degrees)

Source: Timetable of astronomical events by Guy Ottewell

Visit theplanetstoday.com to know which sign presently backdrops the sun.

Want a quick comparison of these dates with the dates of the sun’s entry into astronomical constellations? Click here. Or check out the chart below, which Guy Ottewell posted to his blog in early 2016 and is still valid for 2020. Used with permission.

Chart with astrological signs on left and constellations on right by month.

Dates of sun’s entry into astrological signs versus astronomical constellations are the same in 2020 as in 2016. Chart and more explanation at Guy Ottewell’s blog. Used with permission.

Bottom line: Dates for the sun’s entry into each sign of the zodiac (and corresponding ecliptic longitude) for the year 2020.

Dates of sun’s entry into each constellation of the zodiac

What is the zodiac?



from EarthSky https://ift.tt/2tqUONT
Astrological chart via Wikipedia

An astrological chart, via Wikipedia. Want to see the difference between the sun’s location according to astrology, and the sun’s location according to astronomy? Bookmark this article and then click here for dates of sun’s entry into each constellation of the zodiac.

Astronomy and astrology are different. One difference … astrological signs of the tropical zodiac remain fixed relative to seasonal markers, such as the equinox and solstice points on the sky’s dome. Meanwhile, the constellations of the zodiac (and signs of the sidereal zodiac) slowly but surely shift eastward relative to the equinox and solstice points, over the long course of time, due to a motion of Earth called precession.

Moon lovers! Order this year’s EarthSky lunar calendar here

Also, signs of both the tropical and sidereal zodiac represent equal 30 degree divisions whereas the constellations of the zodiac vary in size.

In a celestial coordinate system commonly used by astronomers and astrologers, the sun resides at the First Point of Aries on the March equinox (0 degrees of longitude on the ecliptic), regardless of the fact that the sun shines in front of the constellation Pisces on the March equinox in our day and age.

Twelve cryptic symbols.

Symbols for the signs of the Zodiac. Both astrologers and astronomers sometimes use these symbols. Image via Wikipedia.

We provide the dates for the sun’s entry into each sign of the tropical zodiac (and corresponding ecliptic longitude) for the year 2020.

Dec 22, 2019: Sun enters sign Capricorn (270 degrees)

Jan 20, 2020: Sun enters sign Aquarius (300 degrees)

Feb 19, 2020: Sun enters sign Pisces (330 degrees)

Mar 20, 2020: Sun enters sign Aries (0 degrees)

April 19, 2020: Sun enters sign Taurus (30 degrees)

May 20, 2020: Sun enters sign Gemini (60 degrees)

June 20, 2020: Sun enters sign Cancer (90 degrees)

July 22, 2020: Sun enters sign Leo (120 degrees)

Aug 22, 2020: Sun enters sign Virgo (150 degrees)

Sep 22, 2020: Sun enters sign Libra (180 degrees)

Oct 22, 2020: Sun enters sign Scorpio (210 degrees)

Nov 21, 2020: Sun enters sign Sagittarius (240 degrees)

Dec 21, 2020: Sun enters sign Capricorn (270 degrees)

Source: Timetable of astronomical events by Guy Ottewell

Visit theplanetstoday.com to know which sign presently backdrops the sun.

Want a quick comparison of these dates with the dates of the sun’s entry into astronomical constellations? Click here. Or check out the chart below, which Guy Ottewell posted to his blog in early 2016 and is still valid for 2020. Used with permission.

Chart with astrological signs on left and constellations on right by month.

Dates of sun’s entry into astrological signs versus astronomical constellations are the same in 2020 as in 2016. Chart and more explanation at Guy Ottewell’s blog. Used with permission.

Bottom line: Dates for the sun’s entry into each sign of the zodiac (and corresponding ecliptic longitude) for the year 2020.

Dates of sun’s entry into each constellation of the zodiac

What is the zodiac?



from EarthSky https://ift.tt/2tqUONT

Quadrantid meteors on night of January 3-4

The annual Quadrantid meteor shower is nominally active for roughly two weeks, from about December 27 until about January 10 each year. However, peak activity lasts less than a day, and – to see the best display – you need to be on Earth’s night side during the Quadrantids’ short peak. The International Meteor Organization (IMO) predicts the 2020 peak will come on January 4 at 8 hours UTC. If that forecast holds, it places the peak around 3 a.m. Eastern Time in North America (2 a.m. Central Time, 1 a.m. Mountain Time and 12 midnight Pacific Time) on January 4. Translate UTC to your time.

The hope is always that the shower peaks at about the same time that the radiant is high up in your sky. That won’t be true for everyone across the globe, of course, but the prediction looks good for North America this year.

Keep in mind that meteor showers are fickle. Thus this prediction might – or might not – hold. So avid meteor watchers across the globe will be on the watch no matter what. As we’ve said before, meteor showers are like fishing. You wait, you watch … sometimes you catch something.

For all of us, some good news. In 2020, the waxing gibbous moon will set way before dawn’s first light, enabling you to watch this shower in a deliciously dark sky in the wee hours before dawn.

Another note about the Quadrantids. The shower is best seen from northerly latitudes because the radiant point for this shower (shown on the sky chart at top) is so far north on the sky’s dome.

Look at the sky chart above. The higher that you see the Big Dipper and the star Arcturus in your sky, the more likely that you’ll see some Quandrantid meteors. From mid-northern latitudes across the globe, the Big Dipper sits on the horizon at nightfall and climbs upward during the night. In the predawn hours, at mid-northern latitudes across the globe, the Big Dipper swings above Polaris the North Star. If the IMO prediction holds – and the peak comes around 8 UTC on January 4, 2020 – North American skywatchers have a decent chance of catching perhaps 15 to 25 meteors per hour. If we’re exceptionally lucky, we might see several times that number.

To find out when the moon sets in your sky, click on this Custom Sunrise Sunset Calendar and remember to check the Moonrise and Moonset box.

Will you see any meteors? Maybe!

Bright streak of a meteor above a tree-filled skyline.

Eliot Herman in Tucson, Arizona caught this early Quadrantid in late December, 2016. The radiant point was below his horizon then, but you can see a piece of the Big Dipper asterism ascending on the right side of the photo. Thanks, Eliot!

You wouldn’t think people would be so determined to watch such an iffy shower. And yet the Quandrantids is one of the year’s most popular showers. Just remember, the Quadrantid shower has a narrow peak, lasting for only a few hours. If you miss the peak – which is easy to do – you won’t see many meteors.

But the pay-off can be good! The Quadrantids can match the meteor rates of the better-known August Perseid and December Geminid showers. The shower has been known to produce up to 50-100 or more meteors per hour in a dark sky.

Also know that this meteor shower favors the Northern Hemisphere because its radiant point – the point in the sky from which the meteors appear to radiate – is far to the north on the sky’s dome. So it’s not a globally watched shower, as many are.

If you’re thinking of watching the Quadrantids, do it. Meteor shower peaks are rarely a certainty. It’s nearly always a gamble that a shower will reward you with a good show.

The Quadrantid shower is named after the defunct 19th century constellation Quadrans Muralis. If you trace the paths of the Quandrantids backward, they appear to radiate from a point where this constellation once reigned in the sky. If you wish, you can locate the Quadrantid radiant in reference to the Big Dipper and the bright star Arcturus. Use the chart at the top of this post.

But you don’t need to find the radiant to enjoy the Quadrantids. You only need a dark, open sky for an hour or so before dawn.

View larger. | EarthSky Facebook friend Susan Jensen caught this beautiful Quadrantid in 2013.

Bottom line: If you’re at a northerly latitude, try the Quadrantid meteor shower from late night January 3 to dawn January 4, 2020. This shower can produce 50-100 meteors per hour, but its peak is short and sweet.

Want more? Try this post. Everything you need to know: Quadrantid meteor shower

Never miss another full moon! EarthSky moon calendar for 2020

EarthSky’s meteor shower guide for 2020

Big and Little Dippers: Noticeable in northern sky



from EarthSky https://ift.tt/2ubiJ4y

The annual Quadrantid meteor shower is nominally active for roughly two weeks, from about December 27 until about January 10 each year. However, peak activity lasts less than a day, and – to see the best display – you need to be on Earth’s night side during the Quadrantids’ short peak. The International Meteor Organization (IMO) predicts the 2020 peak will come on January 4 at 8 hours UTC. If that forecast holds, it places the peak around 3 a.m. Eastern Time in North America (2 a.m. Central Time, 1 a.m. Mountain Time and 12 midnight Pacific Time) on January 4. Translate UTC to your time.

The hope is always that the shower peaks at about the same time that the radiant is high up in your sky. That won’t be true for everyone across the globe, of course, but the prediction looks good for North America this year.

Keep in mind that meteor showers are fickle. Thus this prediction might – or might not – hold. So avid meteor watchers across the globe will be on the watch no matter what. As we’ve said before, meteor showers are like fishing. You wait, you watch … sometimes you catch something.

For all of us, some good news. In 2020, the waxing gibbous moon will set way before dawn’s first light, enabling you to watch this shower in a deliciously dark sky in the wee hours before dawn.

Another note about the Quadrantids. The shower is best seen from northerly latitudes because the radiant point for this shower (shown on the sky chart at top) is so far north on the sky’s dome.

Look at the sky chart above. The higher that you see the Big Dipper and the star Arcturus in your sky, the more likely that you’ll see some Quandrantid meteors. From mid-northern latitudes across the globe, the Big Dipper sits on the horizon at nightfall and climbs upward during the night. In the predawn hours, at mid-northern latitudes across the globe, the Big Dipper swings above Polaris the North Star. If the IMO prediction holds – and the peak comes around 8 UTC on January 4, 2020 – North American skywatchers have a decent chance of catching perhaps 15 to 25 meteors per hour. If we’re exceptionally lucky, we might see several times that number.

To find out when the moon sets in your sky, click on this Custom Sunrise Sunset Calendar and remember to check the Moonrise and Moonset box.

Will you see any meteors? Maybe!

Bright streak of a meteor above a tree-filled skyline.

Eliot Herman in Tucson, Arizona caught this early Quadrantid in late December, 2016. The radiant point was below his horizon then, but you can see a piece of the Big Dipper asterism ascending on the right side of the photo. Thanks, Eliot!

You wouldn’t think people would be so determined to watch such an iffy shower. And yet the Quandrantids is one of the year’s most popular showers. Just remember, the Quadrantid shower has a narrow peak, lasting for only a few hours. If you miss the peak – which is easy to do – you won’t see many meteors.

But the pay-off can be good! The Quadrantids can match the meteor rates of the better-known August Perseid and December Geminid showers. The shower has been known to produce up to 50-100 or more meteors per hour in a dark sky.

Also know that this meteor shower favors the Northern Hemisphere because its radiant point – the point in the sky from which the meteors appear to radiate – is far to the north on the sky’s dome. So it’s not a globally watched shower, as many are.

If you’re thinking of watching the Quadrantids, do it. Meteor shower peaks are rarely a certainty. It’s nearly always a gamble that a shower will reward you with a good show.

The Quadrantid shower is named after the defunct 19th century constellation Quadrans Muralis. If you trace the paths of the Quandrantids backward, they appear to radiate from a point where this constellation once reigned in the sky. If you wish, you can locate the Quadrantid radiant in reference to the Big Dipper and the bright star Arcturus. Use the chart at the top of this post.

But you don’t need to find the radiant to enjoy the Quadrantids. You only need a dark, open sky for an hour or so before dawn.

View larger. | EarthSky Facebook friend Susan Jensen caught this beautiful Quadrantid in 2013.

Bottom line: If you’re at a northerly latitude, try the Quadrantid meteor shower from late night January 3 to dawn January 4, 2020. This shower can produce 50-100 meteors per hour, but its peak is short and sweet.

Want more? Try this post. Everything you need to know: Quadrantid meteor shower

Never miss another full moon! EarthSky moon calendar for 2020

EarthSky’s meteor shower guide for 2020

Big and Little Dippers: Noticeable in northern sky



from EarthSky https://ift.tt/2ubiJ4y

Artificial intelligence could help breast screening save more lives

Mammogram

Right now, the NHS breast cancer screening programme saves around 1,300 lives in the UK each year.

But there are severe NHS staff shortages, particularly in the teams that help diagnose cancer,  with some reports suggesting that up to 1 in 10 diagnostic posts are currently vacant. Throw  in rising demand to the mix , and the future of these services could be in trouble. 

But new technology could help ease the situation. We’ve partnered with Google Health on research to develop artificial intelligence that not only has the potential to change the way we detect breast cancer but could also save the NHS time and money.  

Helping to train a computer 

Our scientists have created a database of anonymised breast cancer scans (mammograms) that have come from breast screening appointments at a number of  NHS breast screening centres around the UK, to be used for research.

Containing over 2.5 million images, this database is the largest and most dynamic of its kind in the world. And it’s available for academic and commercial partners to use, if they have a smart and scientifically sound research proposal that will benefit patients. But before they get access, their proposal is scrutinized by a group of experts, including people affected by cancer.  

That’s where Google Health comes in. Five years ago, Google and researchers from Imperial College London approached our team with a belief that a fancy computer programme could be developed and trained to spot cancer on mammograms.

“Basically, they were trying to teach a machine to read images and it takes an awful lot of images for it to learn so it can get really good at picking up cancer,” says Helen, a member of the group Independent Cancer Patients’ Voice, that brings together patient advocates to help with medical research. She reviewed Google Health’s application to access the database.

Computers with AI capabilities are only as good as the data they’ve been trained on, so for her, our mammogram collection and Google’s technology prowess were a winning combination. 

Results from this mighty research collaboration, published in Nature, show that the learning paid off. The AI software was able to correctly identify cancers in screening images with a similar degree of accuracy as the experts. The computer programme also reduced the number of errors, including cases where cancer is flagged incorrectly or those that are missed altogether. 

Currently, 2 experts review breast screening scans. But the system isn’t perfect, as screening can miss some cancers and pick up ones that wouldn’t have gone on to cause problems.

“It now looks from this research that having the combination of a human eye and a machine eye over the images could actually give more accurate results,” says Helen. She is referring to the study’s finding that AI reduced false positive results. These are ‘false alarms’ that can occur when someone gets an abnormal result, but they don’t have cancer. 

“That will reduce loads of anxiety for women,” says Helen, who was diagnosed with breast cancer in 2004 and finished reconstruction surgery in 2014. It will also save the NHS time and money by reducing the number of patients who are called back for further tests. 

Artificial intelligence in a real scenario

Professor Ken Young works for the NHS and manages our mammogram collection. He and his colleagues helped Google Health analyse the data and design the trial to make it the most realistic AI study in breast cancer detection to date. 

“What I think is most interesting about this study is its realism,” says Young. “What’s unusual is that it compares the algorithm to a totally realistic clinical scenario.” 

Past studies have used specially selected mammograms that were analysed in a somewhat artificial setting. For example, some other programmes have been tested on a set of images that have more cancer cases than would be found in the general population. 

But in the latest study, researchers compared real decisions made by radiologists analysing the scans of people attending the NHS breast screening programme. 

“We have a sample that is representative of all the women that might come through breast screening,” says Young. “It includes easy cases, difficult cases and everything in between.” 

And thanks to this collaboration, the data set is even richer than it was before. Around 100,000 more normal cases have been added to the database, which are now available to other researchers using the scan collection.  

Giving the gift of time 

NHS staff could also benefit from the partnership. A recent review suggested that this kind of tech will give radiologists ‘the gift of time’, instead of replacing them.

“All the radiologists I know aren’t worried about AI at all,” says Young. “I think they’d be delighted to have some of the quite monotonous work of reading mammograms done for them, so they’re freed up to do other things.” 

Keeping patient data safe

The other concern when it comes to developing AI software is data protection, something that Young, Helen and the team have carefully thought through.

“One of the concerns that comes through is patient confidentiality,” says Helen, who has taken part in trials herself. “It’s very important that I sit there on the lay side to make certain that everything is anonymised, and the ethics are checked.”

Before images enter the database, they’re immediately de-identified so there is no way that a researcher can find out who the mammograms belong to. The scans don’t include any personal information, which is “stripped out before we add the image to the database and share it with researchers,” says Young.

And research groups who are granted access to the images also have to agree to certain conditions, like keeping the patient data confidential and not using it for any other purpose than the development of AI screening algorithms.

AI still has a lot to learn

This well-trained algorithm is still in its early stages, but now has a firm foundation of knowledge to build on. Next the team need to test on a wider population and to see how radiologists can benefit from using the algorithm in the clinic. 

“I genuinely think the potential here is enormous,” says Young. “Breast cancer screening has a number of problems that could be tackled by the introduction of artificial intelligence.”

“These early studies using AI are the beginning of something quite big that will revolutionise medicine, this is just one of the first examples.” 

Gabi 



from Cancer Research UK – Science blog https://ift.tt/2ZRLRtv
Mammogram

Right now, the NHS breast cancer screening programme saves around 1,300 lives in the UK each year.

But there are severe NHS staff shortages, particularly in the teams that help diagnose cancer,  with some reports suggesting that up to 1 in 10 diagnostic posts are currently vacant. Throw  in rising demand to the mix , and the future of these services could be in trouble. 

But new technology could help ease the situation. We’ve partnered with Google Health on research to develop artificial intelligence that not only has the potential to change the way we detect breast cancer but could also save the NHS time and money.  

Helping to train a computer 

Our scientists have created a database of anonymised breast cancer scans (mammograms) that have come from breast screening appointments at a number of  NHS breast screening centres around the UK, to be used for research.

Containing over 2.5 million images, this database is the largest and most dynamic of its kind in the world. And it’s available for academic and commercial partners to use, if they have a smart and scientifically sound research proposal that will benefit patients. But before they get access, their proposal is scrutinized by a group of experts, including people affected by cancer.  

That’s where Google Health comes in. Five years ago, Google and researchers from Imperial College London approached our team with a belief that a fancy computer programme could be developed and trained to spot cancer on mammograms.

“Basically, they were trying to teach a machine to read images and it takes an awful lot of images for it to learn so it can get really good at picking up cancer,” says Helen, a member of the group Independent Cancer Patients’ Voice, that brings together patient advocates to help with medical research. She reviewed Google Health’s application to access the database.

Computers with AI capabilities are only as good as the data they’ve been trained on, so for her, our mammogram collection and Google’s technology prowess were a winning combination. 

Results from this mighty research collaboration, published in Nature, show that the learning paid off. The AI software was able to correctly identify cancers in screening images with a similar degree of accuracy as the experts. The computer programme also reduced the number of errors, including cases where cancer is flagged incorrectly or those that are missed altogether. 

Currently, 2 experts review breast screening scans. But the system isn’t perfect, as screening can miss some cancers and pick up ones that wouldn’t have gone on to cause problems.

“It now looks from this research that having the combination of a human eye and a machine eye over the images could actually give more accurate results,” says Helen. She is referring to the study’s finding that AI reduced false positive results. These are ‘false alarms’ that can occur when someone gets an abnormal result, but they don’t have cancer. 

“That will reduce loads of anxiety for women,” says Helen, who was diagnosed with breast cancer in 2004 and finished reconstruction surgery in 2014. It will also save the NHS time and money by reducing the number of patients who are called back for further tests. 

Artificial intelligence in a real scenario

Professor Ken Young works for the NHS and manages our mammogram collection. He and his colleagues helped Google Health analyse the data and design the trial to make it the most realistic AI study in breast cancer detection to date. 

“What I think is most interesting about this study is its realism,” says Young. “What’s unusual is that it compares the algorithm to a totally realistic clinical scenario.” 

Past studies have used specially selected mammograms that were analysed in a somewhat artificial setting. For example, some other programmes have been tested on a set of images that have more cancer cases than would be found in the general population. 

But in the latest study, researchers compared real decisions made by radiologists analysing the scans of people attending the NHS breast screening programme. 

“We have a sample that is representative of all the women that might come through breast screening,” says Young. “It includes easy cases, difficult cases and everything in between.” 

And thanks to this collaboration, the data set is even richer than it was before. Around 100,000 more normal cases have been added to the database, which are now available to other researchers using the scan collection.  

Giving the gift of time 

NHS staff could also benefit from the partnership. A recent review suggested that this kind of tech will give radiologists ‘the gift of time’, instead of replacing them.

“All the radiologists I know aren’t worried about AI at all,” says Young. “I think they’d be delighted to have some of the quite monotonous work of reading mammograms done for them, so they’re freed up to do other things.” 

Keeping patient data safe

The other concern when it comes to developing AI software is data protection, something that Young, Helen and the team have carefully thought through.

“One of the concerns that comes through is patient confidentiality,” says Helen, who has taken part in trials herself. “It’s very important that I sit there on the lay side to make certain that everything is anonymised, and the ethics are checked.”

Before images enter the database, they’re immediately de-identified so there is no way that a researcher can find out who the mammograms belong to. The scans don’t include any personal information, which is “stripped out before we add the image to the database and share it with researchers,” says Young.

And research groups who are granted access to the images also have to agree to certain conditions, like keeping the patient data confidential and not using it for any other purpose than the development of AI screening algorithms.

AI still has a lot to learn

This well-trained algorithm is still in its early stages, but now has a firm foundation of knowledge to build on. Next the team need to test on a wider population and to see how radiologists can benefit from using the algorithm in the clinic. 

“I genuinely think the potential here is enormous,” says Young. “Breast cancer screening has a number of problems that could be tackled by the introduction of artificial intelligence.”

“These early studies using AI are the beginning of something quite big that will revolutionise medicine, this is just one of the first examples.” 

Gabi 



from Cancer Research UK – Science blog https://ift.tt/2ZRLRtv