Close-up on Cassiopeia the Queen

Cassiopeia via smokymtnastro.org.

The constellation Cassiopeia the Queen can be found high in the northeast on October evenings, not far from Polaris, the North Star. At any time of year, you can use the Big Dipper to find Cassiopeia. These two star formations are like riders on opposite side of a Ferris wheel. They’re part of a great spinning wheel of stars seen moving counterclockwise around Polaris, the North Star, once each day. As Cassiopeia rises upward, the Big Dipper plunges downward, and vice versa.

Some of you know how to star-hop to Polaris, the North Star, by using the Big Dipper’s pointer stars, as displayed on the sky chart below. Because the Big Dipper’s handle and Cassiopeia shine on opposite sides of Polaris, an imaginary line from any star on the Big Dipper handle through Polaris reliably points to Cassiopeia.

The 2020 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

You can find Cassiopeia somewhere in the north for much of the year, and much of the night. Here it is on an October evening, relative to Polaris, the North Star.

But you won’t need these details to find this constellation. That’s because Cassiopeia is very easy to pick out. It’s small and compact and looks like the letter M or W, depending on the time of night and time of year.

Like the Big Dipper, Cassiopeia can be seen even on moonlit nights.

Bonus for you if you live north of about 40 degrees north latitude, about the latitude of New York City! From that latitude and farther north, the Big Dipper and Cassiopeia are both circumpolar. That means they’re always above the horizon at any time of night, all year round.

Upside-down Cassiopeia on Mercator globe.

Upside-down Cassiopeia via Johannes Hevelius.

Cassiopeia used to be known among astronomers and skywatchers alike as Cassiopeia’s Chair. In the 1930s, the International Astronomical Union gave this constellation the official name of Cassiopeia the Queen.

Cassiopeia was a queen in ancient Greek mythology. According to legend, she boasted she was more beautiful than the sea nymphs, called the Nereids. Her boast angered Poseidon, god of the sea, who sent a sea monster, Cetus, to ravage the kingdom. To pacify the monster, Cassiopeia’s daughter, Princess Andromeda, was left tied to a rock by the sea. Cetus was about to devour her when Perseus the Hero looked down upon her from Pegasus, the Flying Horse. Perseus rescued the Princess, and all lived happily.

The gods were so pleased, that all of these characters were elevated to the heavens as stars. Only Cassiopeia suffered an indignity – her vanity caused her to be bound to a chair and placed in the heavens so that, as she revolves around the north celestial pole, she is sometimes in an upside-down position.

The official borders of the constellation Cassiopeia (and all 88 constellations) were drawn up by the International Astronomers Union in the 1930’s. Read more.

Bottom line: Spot the constellation Cassiopeia the Queen somewhere in the northern sky during much of the year, and throughout much of the night.

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

Cassiopeia via smokymtnastro.org.

The constellation Cassiopeia the Queen can be found high in the northeast on October evenings, not far from Polaris, the North Star. At any time of year, you can use the Big Dipper to find Cassiopeia. These two star formations are like riders on opposite side of a Ferris wheel. They’re part of a great spinning wheel of stars seen moving counterclockwise around Polaris, the North Star, once each day. As Cassiopeia rises upward, the Big Dipper plunges downward, and vice versa.

Some of you know how to star-hop to Polaris, the North Star, by using the Big Dipper’s pointer stars, as displayed on the sky chart below. Because the Big Dipper’s handle and Cassiopeia shine on opposite sides of Polaris, an imaginary line from any star on the Big Dipper handle through Polaris reliably points to Cassiopeia.

The 2020 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

You can find Cassiopeia somewhere in the north for much of the year, and much of the night. Here it is on an October evening, relative to Polaris, the North Star.

But you won’t need these details to find this constellation. That’s because Cassiopeia is very easy to pick out. It’s small and compact and looks like the letter M or W, depending on the time of night and time of year.

Like the Big Dipper, Cassiopeia can be seen even on moonlit nights.

Bonus for you if you live north of about 40 degrees north latitude, about the latitude of New York City! From that latitude and farther north, the Big Dipper and Cassiopeia are both circumpolar. That means they’re always above the horizon at any time of night, all year round.

Upside-down Cassiopeia on Mercator globe.

Upside-down Cassiopeia via Johannes Hevelius.

Cassiopeia used to be known among astronomers and skywatchers alike as Cassiopeia’s Chair. In the 1930s, the International Astronomical Union gave this constellation the official name of Cassiopeia the Queen.

Cassiopeia was a queen in ancient Greek mythology. According to legend, she boasted she was more beautiful than the sea nymphs, called the Nereids. Her boast angered Poseidon, god of the sea, who sent a sea monster, Cetus, to ravage the kingdom. To pacify the monster, Cassiopeia’s daughter, Princess Andromeda, was left tied to a rock by the sea. Cetus was about to devour her when Perseus the Hero looked down upon her from Pegasus, the Flying Horse. Perseus rescued the Princess, and all lived happily.

The gods were so pleased, that all of these characters were elevated to the heavens as stars. Only Cassiopeia suffered an indignity – her vanity caused her to be bound to a chair and placed in the heavens so that, as she revolves around the north celestial pole, she is sometimes in an upside-down position.

The official borders of the constellation Cassiopeia (and all 88 constellations) were drawn up by the International Astronomers Union in the 1930’s. Read more.

Bottom line: Spot the constellation Cassiopeia the Queen somewhere in the northern sky during much of the year, and throughout much of the night.

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

Found Cassiopeia? Now look for Perseus

The constellation Cassiopeia is M- or W-shaped, ascending in the northeast on Northern Hemisphere autumn evenings. Perseus follows Cassiopeia in a great arc around the northern sky. Be sure to look for the star Algol, sometimes called the Ghoul Star or Demon Star … a perfect star for Halloween!

Let’s say you’re in the Northern Hemisphere, and you’re looking in a dark sky during the evening in autumn or winter. You can see the easy-to-spot constellation Cassiopeia the Queen, with its distinctive M or W shape, depending on what time of night you see it. What else should you look for? Try identifying the constellation next-door to Cassiopeia, which is called Perseus the Hero. As seen from our part of the globe, Perseus rises in the northeast behind Cassiopeia and follows Cassiopeia in a great arc across the northern night sky.

Cassiopeia is easy to identify and so it is one of the most famous constellations in the sky. Perseus is fainter than Cassiopeia, and its stars are not so easy to identify. But if you have access to a dark sky, you’ll spot the graceful shape of Perseus. I always think of this constellation as “dancing,” although its association is one of the most gruesome in skylore. See the image and caption below:

The constellation Perseus. In skylore, Perseus was said to have beheaded Medusa, a witch who had snakes in place of hair. This image is from Urania’s Mirror, a set of constellation cards published in London around 1825. Image via Wikimedia Commons.

You’ll see both Cassiopeia and Perseus in the northeast on an October evening, and higher up in the evening sky in late autumn and winter. Or, as night passes, you’ll see them both ascending in the northeast – then arcing high in the north – then descending in the northwest – with Perseus following Cassiopeia all the while. Both Perseus and Cassiopeia are considered to be circumpolar from about 40 degrees N. latitude to further north. In other words, as seen from northern parts of the U.S. and Canada, they never set below the horizon, but instead circle endlessly around Polaris, the North Star.

The brightest star in Cassiopeia is Shedar.

The brightest star in Perseus is Mirfak, and you’ll also want to identify the most famous star in Perseus: Algol, the Demon Star.

After you’ve found Cassiopeia and Perseus, be sure to scan with your binoculars between them. Assuming your sky is dark, you’ll easily spot the magnificent Double Cluster in Perseus.

The constellation Cassiopeia points out the Double Cluster in northern tip of the constellation Perseus. Faintly visible to the unaided eye on a dark night, it’s better viewed with an optical aid. The Double Cluster nearly marks the radiant of the Perseid meteor shower. Photo credit: madmiked

View larger.| The Double Cluster in Perseus, via Tom Wildoner at The Dark Side Observatory in Weatherly, Pennsylvania.

And, although they are best seen in the evening in autumn and winter, you can also see Cassiopeia and Perseus in the latter part of Northern Hemisphere summer, from late night until dawn. The annual Perseid meteor shower peaks around August 12 or 13, and if you trace the paths of these Perseid meteors backwards, they will appear to originate between these constellations.

The radiant point of August’s famous Perseid meteor shower is between Cassiopeia and Perseus. Chart via SkyandTelescope.com

View at EarthSky Community Photos. | Tom Wildoner of the Dark Side Observatory in Weatherly, Pennsylvania, has an automatic camera set-up for meteor observing. He caught this one on August 11, 2019, and wrote: “You can see this bright meteor streak above center near the constellation Cassiopeia (sideways W) and pointing in the direction of Perseus. The brighter stars have been enhanced in this image to help orient your view, North is marked on the image.” Thanks, Tom!

Bottom line: Look for the constellations Cassiopeia and Perseus in the northern evening sky during the upcoming winter months.

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

The constellation Cassiopeia is M- or W-shaped, ascending in the northeast on Northern Hemisphere autumn evenings. Perseus follows Cassiopeia in a great arc around the northern sky. Be sure to look for the star Algol, sometimes called the Ghoul Star or Demon Star … a perfect star for Halloween!

Let’s say you’re in the Northern Hemisphere, and you’re looking in a dark sky during the evening in autumn or winter. You can see the easy-to-spot constellation Cassiopeia the Queen, with its distinctive M or W shape, depending on what time of night you see it. What else should you look for? Try identifying the constellation next-door to Cassiopeia, which is called Perseus the Hero. As seen from our part of the globe, Perseus rises in the northeast behind Cassiopeia and follows Cassiopeia in a great arc across the northern night sky.

Cassiopeia is easy to identify and so it is one of the most famous constellations in the sky. Perseus is fainter than Cassiopeia, and its stars are not so easy to identify. But if you have access to a dark sky, you’ll spot the graceful shape of Perseus. I always think of this constellation as “dancing,” although its association is one of the most gruesome in skylore. See the image and caption below:

The constellation Perseus. In skylore, Perseus was said to have beheaded Medusa, a witch who had snakes in place of hair. This image is from Urania’s Mirror, a set of constellation cards published in London around 1825. Image via Wikimedia Commons.

You’ll see both Cassiopeia and Perseus in the northeast on an October evening, and higher up in the evening sky in late autumn and winter. Or, as night passes, you’ll see them both ascending in the northeast – then arcing high in the north – then descending in the northwest – with Perseus following Cassiopeia all the while. Both Perseus and Cassiopeia are considered to be circumpolar from about 40 degrees N. latitude to further north. In other words, as seen from northern parts of the U.S. and Canada, they never set below the horizon, but instead circle endlessly around Polaris, the North Star.

The brightest star in Cassiopeia is Shedar.

The brightest star in Perseus is Mirfak, and you’ll also want to identify the most famous star in Perseus: Algol, the Demon Star.

After you’ve found Cassiopeia and Perseus, be sure to scan with your binoculars between them. Assuming your sky is dark, you’ll easily spot the magnificent Double Cluster in Perseus.

The constellation Cassiopeia points out the Double Cluster in northern tip of the constellation Perseus. Faintly visible to the unaided eye on a dark night, it’s better viewed with an optical aid. The Double Cluster nearly marks the radiant of the Perseid meteor shower. Photo credit: madmiked

View larger.| The Double Cluster in Perseus, via Tom Wildoner at The Dark Side Observatory in Weatherly, Pennsylvania.

And, although they are best seen in the evening in autumn and winter, you can also see Cassiopeia and Perseus in the latter part of Northern Hemisphere summer, from late night until dawn. The annual Perseid meteor shower peaks around August 12 or 13, and if you trace the paths of these Perseid meteors backwards, they will appear to originate between these constellations.

The radiant point of August’s famous Perseid meteor shower is between Cassiopeia and Perseus. Chart via SkyandTelescope.com

View at EarthSky Community Photos. | Tom Wildoner of the Dark Side Observatory in Weatherly, Pennsylvania, has an automatic camera set-up for meteor observing. He caught this one on August 11, 2019, and wrote: “You can see this bright meteor streak above center near the constellation Cassiopeia (sideways W) and pointing in the direction of Perseus. The brighter stars have been enhanced in this image to help orient your view, North is marked on the image.” Thanks, Tom!

Bottom line: Look for the constellations Cassiopeia and Perseus in the northern evening sky during the upcoming winter months.

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

Spiral galaxy in profile

Image via ESA/Hubble & NASA, D. Rosario.

This Hubble Telescope image, released by ESA on October 11, 2019, shows a spiral galaxy oriented sideways. The dust and spiral arms of spiral galaxies, like our own Milky Way, appear flat when viewed edge-on. The galaxy in the image, called NGC 3717, is located about 60 million light-years away in the constellation of Hydra (The Sea Serpent).

In a spiral galaxy, the stars, gas and dust are gathered in spiral arms that spread outward from the galaxy’s center. Because, in this image, we’re looking at NGC 3717 edge-on, we can’t see this galaxy’s spiral arms. But, according to a statement from ESA:

Seeing a spiral almost in profile, as Hubble has here, can provide a vivid sense of its three-dimensional shape. Through most of their expanse, spiral galaxies are shaped like a thin pancake. At their cores, though, they have bright, spherical, star-filled bulges that extend above and below this disc, giving these galaxies a shape somewhat like that of a flying saucer when they are seen edge-on.

NGC 3717 is not captured perfectly edge-on in this image; the nearer part of the galaxy is tilted ever so slightly down, and the far side tilted up. This angle lets you see across the disc and the galaxy’s central bulge (of which only one side is visible).

Via ESA

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

Image via ESA/Hubble & NASA, D. Rosario.

This Hubble Telescope image, released by ESA on October 11, 2019, shows a spiral galaxy oriented sideways. The dust and spiral arms of spiral galaxies, like our own Milky Way, appear flat when viewed edge-on. The galaxy in the image, called NGC 3717, is located about 60 million light-years away in the constellation of Hydra (The Sea Serpent).

In a spiral galaxy, the stars, gas and dust are gathered in spiral arms that spread outward from the galaxy’s center. Because, in this image, we’re looking at NGC 3717 edge-on, we can’t see this galaxy’s spiral arms. But, according to a statement from ESA:

Seeing a spiral almost in profile, as Hubble has here, can provide a vivid sense of its three-dimensional shape. Through most of their expanse, spiral galaxies are shaped like a thin pancake. At their cores, though, they have bright, spherical, star-filled bulges that extend above and below this disc, giving these galaxies a shape somewhat like that of a flying saucer when they are seen edge-on.

NGC 3717 is not captured perfectly edge-on in this image; the nearer part of the galaxy is tilted ever so slightly down, and the far side tilted up. This angle lets you see across the disc and the galaxy’s central bulge (of which only one side is visible).

Via ESA

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

News digest – screening review, exercise, NICE decisions and psoriasis

Cancer screening review calls for more flexible screening hours, among other things

This week a review of cancer screening programmes by the former National Cancer Director, Sir Mike Richards, was published. Many news outlets focused on recommendations to make screening fit in with people’s increasingly busy lifestyles, by allowing screening appointments to be made on weekends and during lunch breaks. Other recommendations in the review included reuniting responsibility for screening programmes in England under a single organisation and improving IT to reduce screening errors, as our blog post explains.

Ban on junk food advertising coming to Wales

A new document published this week, outlined a new strategy titled Healthy Weight: Healthy Wales, which aims to reduce obesity levels. Some of the measures outlined include banning junk food advertising in many public places and at sporting events, and taking action against hot food takeaways and promotions on junk food near schools. Experts praised the “bold action” from the Welsh Government, but warned that the strategy had to be delivered as promised. Wales Online has the story.

Exercise may help with cancer treatment

A study this week, reported by The New York Times, found that exercise should be prescribed like medicine for some cancer patients and could even act as a preventative measure against cancer. The report suggests that exercise can help lower the risk of developing kidney, bladder, breast, colon, stomach, endometrial and oesophageal cancers. And exercise seemed to reduce people with cancer’s feelings of anxiety and improve fatigue. We’ve looked at the benefits of exercise with cancer before, in our blog post.

New survey shows continuing pressure on NHS systems

New survey results have revealed ongoing problems with rota gaps, unfilled posts and high levels of sickness absence in the NHS. The survey from the Royal Colleges of Physicians in London, Edinburgh and Glasgow further highlights the intense pressures the NHS is coming under and was well summarised in PharmaTimes.

Lack of diagnostic scanners causing problems on the NHS

A new study from the UK Lung Cancer Coalition found there aren’t enough scanners for staff to use, which could be delaying diagnosis and treatment. The report also highlighted the extent of NHS staff shortages – in the UK there are seven radiologists per 100,000 people, much less than the EU average of 12. ITV news has this one.

New breast cancer drug made available on the NHS in England

The National Institute for Health and Care Excellence (NICE) has approved the use of a targeted drug, neratinib (Nerlynx), for some people with early breast cancer on the NHS in England. Our news report provides all you need to know about the approval, who it’s for and the potential side effects.

Gene testing kit 23andMe comes under fire from competitors

23andMe, a genetic test that can be bought online, has been criticised by competitors at the annual meeting of the American Society of Human Genetics. Representatives from Invitae warned the test could be giving false reassurance to some people, by missing some DNA faults linked to cancer. But 23andMe have hit back at the “misleading characterisation”, you can read the full debate in The Guardian or STATNews.

And finally

Reported by The New York Times and Newsweek, a review of 58 studies found that people with psoriasis had an increased risk of some types of cancer. But there are a lot of questions remaining. The authors of the study acknowledge that smoking, obesity and drinking lots of alcohol, which we know can cause cancer, have all been shown to be more common in people with psoriasis, which may be muddying the water when it comes to assessing risk. Researchers need to make sure these other factors aren’t playing a role before they can be confident that there’s a direct link.

Ethan

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

Cancer screening review calls for more flexible screening hours, among other things

This week a review of cancer screening programmes by the former National Cancer Director, Sir Mike Richards, was published. Many news outlets focused on recommendations to make screening fit in with people’s increasingly busy lifestyles, by allowing screening appointments to be made on weekends and during lunch breaks. Other recommendations in the review included reuniting responsibility for screening programmes in England under a single organisation and improving IT to reduce screening errors, as our blog post explains.

Ban on junk food advertising coming to Wales

A new document published this week, outlined a new strategy titled Healthy Weight: Healthy Wales, which aims to reduce obesity levels. Some of the measures outlined include banning junk food advertising in many public places and at sporting events, and taking action against hot food takeaways and promotions on junk food near schools. Experts praised the “bold action” from the Welsh Government, but warned that the strategy had to be delivered as promised. Wales Online has the story.

Exercise may help with cancer treatment

A study this week, reported by The New York Times, found that exercise should be prescribed like medicine for some cancer patients and could even act as a preventative measure against cancer. The report suggests that exercise can help lower the risk of developing kidney, bladder, breast, colon, stomach, endometrial and oesophageal cancers. And exercise seemed to reduce people with cancer’s feelings of anxiety and improve fatigue. We’ve looked at the benefits of exercise with cancer before, in our blog post.

New survey shows continuing pressure on NHS systems

New survey results have revealed ongoing problems with rota gaps, unfilled posts and high levels of sickness absence in the NHS. The survey from the Royal Colleges of Physicians in London, Edinburgh and Glasgow further highlights the intense pressures the NHS is coming under and was well summarised in PharmaTimes.

Lack of diagnostic scanners causing problems on the NHS

A new study from the UK Lung Cancer Coalition found there aren’t enough scanners for staff to use, which could be delaying diagnosis and treatment. The report also highlighted the extent of NHS staff shortages – in the UK there are seven radiologists per 100,000 people, much less than the EU average of 12. ITV news has this one.

New breast cancer drug made available on the NHS in England

The National Institute for Health and Care Excellence (NICE) has approved the use of a targeted drug, neratinib (Nerlynx), for some people with early breast cancer on the NHS in England. Our news report provides all you need to know about the approval, who it’s for and the potential side effects.

Gene testing kit 23andMe comes under fire from competitors

23andMe, a genetic test that can be bought online, has been criticised by competitors at the annual meeting of the American Society of Human Genetics. Representatives from Invitae warned the test could be giving false reassurance to some people, by missing some DNA faults linked to cancer. But 23andMe have hit back at the “misleading characterisation”, you can read the full debate in The Guardian or STATNews.

And finally

Reported by The New York Times and Newsweek, a review of 58 studies found that people with psoriasis had an increased risk of some types of cancer. But there are a lot of questions remaining. The authors of the study acknowledge that smoking, obesity and drinking lots of alcohol, which we know can cause cancer, have all been shown to be more common in people with psoriasis, which may be muddying the water when it comes to assessing risk. Researchers need to make sure these other factors aren’t playing a role before they can be confident that there’s a direct link.

Ethan

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

Will you see Venus and Mercury after sunset?

Have you seen Venus yet? And will you also see fainter Mercury near Venus? Both are in the western twilight after sunset. But whether you’ll see them depends on how far north or south you are on Earth’s globe. If you live as far north as Anchorage, Alaska, the sun, Mercury and Venus set at nearly the same time in your sky, so you’re sure to miss the planets. But if you live as far south as New Zealand’s South Island, Mercury and Venus stay out well over two hours after sunset. From far-southern latitudes, your chance of spotting these worlds is about as good as it gets in October 2019. Northerly latitudes … not so much. But we know you love a challenge!

The featured sky chart at top is for mid-northern latitudes in the Northern Hemisphere. The sky chart below shows the sky scene for around 35 degrees south latitude. The steeper tilt of the ecliptic (green line on our sky charts) relative to the sunset horizon gives the Southern Hemisphere the advantage for viewing the evening planets. At this time of year, the ecliptic hits the horizon at a shallow angle at northerly latitudes. The solar system planets always reside on or near the ecliptic – Earth’s orbital plane projected onto the constellations of the zodiac.

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

Contrast the tilt of the ecliptic above at temperate latitudes in the Southern Hemisphere, with the tilt of the ecliptic on the featured chart at top for mid-northern latitudes.

Dazzling Venus shines close to Mercury on the sky’s dome. So look first for Venus, then watch for Mercury to pop out later, with either the unaided eye or binoculars. You may catch Venus 1/2 hour or sooner after sundown, because Venus ranks as the third-brightest heavenly body, after the sun and moon, respectively. Although Mercury is easily as bright as a 1st-magnitude star, Venus now outshines Mercury by about 35 times. Mercury is slowly dimming by the day, so Venus will outshine Mercury by about 45 times near the end of the month.

We give the approximate setting times for Mercury and Venus for these next several days at various latitudes (presuming a level and unobstructed horizon):

35 degrees north latitude:
Mercury sets 1 hour after the sun
Venus sets 50 minutes after the sun

Equator (0 degrees latitude):
Mercury sets 1 1/2 hours after the sun
Venus sets 1 hour after the sun

35 degrees south latitude:
Mercury sets 2 hours after the sun
Venus sets 1 1/3 hours after the sun

Want more precision for your part of the world? Visit TimeandDate.com.

Mercury is fairly easy to see in the northern tropics and the Southern Hemisphere for two reasons. First, Mercury is near its greatest elongation of 25 degrees east of the sun (October 20, 2019), which places Mercury in the western sky after sunset. Although the elongation of Mercury is the same for the world as a whole, the tilt of the ecliptic favors the northern tropics and the Southern Hemisphere.

Visit AstroPixels.com to know Mercury’s solar elongation for each day of the year

Spring sunsets find the ecliptic intersecting the horizon at a steep angle, whereas autumn sunsets find the ecliptic intersecting the horizon at a shallow angle. Because it’s spring in the Southern Hemisphere and autumn in the Northern Hemisphere, the Southern Hemisphere has the advantage for viewing the evening planets. Moreover, Mercury is south of the ecliptic, which adds that much more to the Southern Hemisphere’s advantage and the Northern Hemisphere’s disadvantage.

The lucky residents in the Southern Hemisphere and the northern tropics have a golden opportunity to spot Mercury near Venus in the evening sky from now until early November.

And, no matter where you are on Earth, a great time to watch for Mercury and Venus will be toward this month’s end – on or near October 29, 2019 – when the young moon passes through this part of the sky. Think photo opportunity! Here’s the Southern Hemisphere view:

Southern Hemisphere view. The moon joins up with Venus and Mercury around the end of this month. This chart shows an optimum Southern Hemisphere view, specifically, in this case, from Cape Town, Africa, at dusk October 29, 2019. If you live in the Northern Hemisphere, this sweep of the young moon past the planets will give you, too, a good opportunity to glimpse them. Read more.

And here’s the Northern Hemisphere view. Notice that the ecliptic – shown as a green line on our charts – makes a narrow angle with the western horizon in the evening. That’s why Venus and Mercury are so much harder to see from this hemisphere, this month.

Northern Hemisphere view. This chart is for North American mid-northern latitudes. Same planets, same sunset sky … but the narrower angle of the ecliptic makes the planets harder to see. Read more.

By the way, when Mercury goes back into the sun’s glare – and passes between the Earth and sun – it will cross directly in front of the sun, creating what’s called a transit of Mercury. Although much more common than transits of Venus, a transit of Mercury happens only 14 times in the 21st century (2001 to 2100). Read more about the Mercury transit on November 11, 2019.

Bottom line: The Southern Hemisphere enjoys a superb view of Mercury and Venus in October 2019. If you live at northerly latitudes, have binoculars handy!

from EarthSky https://ift.tt/2Ms9fsn

Have you seen Venus yet? And will you also see fainter Mercury near Venus? Both are in the western twilight after sunset. But whether you’ll see them depends on how far north or south you are on Earth’s globe. If you live as far north as Anchorage, Alaska, the sun, Mercury and Venus set at nearly the same time in your sky, so you’re sure to miss the planets. But if you live as far south as New Zealand’s South Island, Mercury and Venus stay out well over two hours after sunset. From far-southern latitudes, your chance of spotting these worlds is about as good as it gets in October 2019. Northerly latitudes … not so much. But we know you love a challenge!

The featured sky chart at top is for mid-northern latitudes in the Northern Hemisphere. The sky chart below shows the sky scene for around 35 degrees south latitude. The steeper tilt of the ecliptic (green line on our sky charts) relative to the sunset horizon gives the Southern Hemisphere the advantage for viewing the evening planets. At this time of year, the ecliptic hits the horizon at a shallow angle at northerly latitudes. The solar system planets always reside on or near the ecliptic – Earth’s orbital plane projected onto the constellations of the zodiac.

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

Contrast the tilt of the ecliptic above at temperate latitudes in the Southern Hemisphere, with the tilt of the ecliptic on the featured chart at top for mid-northern latitudes.

Dazzling Venus shines close to Mercury on the sky’s dome. So look first for Venus, then watch for Mercury to pop out later, with either the unaided eye or binoculars. You may catch Venus 1/2 hour or sooner after sundown, because Venus ranks as the third-brightest heavenly body, after the sun and moon, respectively. Although Mercury is easily as bright as a 1st-magnitude star, Venus now outshines Mercury by about 35 times. Mercury is slowly dimming by the day, so Venus will outshine Mercury by about 45 times near the end of the month.

We give the approximate setting times for Mercury and Venus for these next several days at various latitudes (presuming a level and unobstructed horizon):

35 degrees north latitude:
Mercury sets 1 hour after the sun
Venus sets 50 minutes after the sun

Equator (0 degrees latitude):
Mercury sets 1 1/2 hours after the sun
Venus sets 1 hour after the sun

35 degrees south latitude:
Mercury sets 2 hours after the sun
Venus sets 1 1/3 hours after the sun

Want more precision for your part of the world? Visit TimeandDate.com.

Mercury is fairly easy to see in the northern tropics and the Southern Hemisphere for two reasons. First, Mercury is near its greatest elongation of 25 degrees east of the sun (October 20, 2019), which places Mercury in the western sky after sunset. Although the elongation of Mercury is the same for the world as a whole, the tilt of the ecliptic favors the northern tropics and the Southern Hemisphere.

Visit AstroPixels.com to know Mercury’s solar elongation for each day of the year

Spring sunsets find the ecliptic intersecting the horizon at a steep angle, whereas autumn sunsets find the ecliptic intersecting the horizon at a shallow angle. Because it’s spring in the Southern Hemisphere and autumn in the Northern Hemisphere, the Southern Hemisphere has the advantage for viewing the evening planets. Moreover, Mercury is south of the ecliptic, which adds that much more to the Southern Hemisphere’s advantage and the Northern Hemisphere’s disadvantage.

The lucky residents in the Southern Hemisphere and the northern tropics have a golden opportunity to spot Mercury near Venus in the evening sky from now until early November.

And, no matter where you are on Earth, a great time to watch for Mercury and Venus will be toward this month’s end – on or near October 29, 2019 – when the young moon passes through this part of the sky. Think photo opportunity! Here’s the Southern Hemisphere view:

Southern Hemisphere view. The moon joins up with Venus and Mercury around the end of this month. This chart shows an optimum Southern Hemisphere view, specifically, in this case, from Cape Town, Africa, at dusk October 29, 2019. If you live in the Northern Hemisphere, this sweep of the young moon past the planets will give you, too, a good opportunity to glimpse them. Read more.

And here’s the Northern Hemisphere view. Notice that the ecliptic – shown as a green line on our charts – makes a narrow angle with the western horizon in the evening. That’s why Venus and Mercury are so much harder to see from this hemisphere, this month.

Northern Hemisphere view. This chart is for North American mid-northern latitudes. Same planets, same sunset sky … but the narrower angle of the ecliptic makes the planets harder to see. Read more.

By the way, when Mercury goes back into the sun’s glare – and passes between the Earth and sun – it will cross directly in front of the sun, creating what’s called a transit of Mercury. Although much more common than transits of Venus, a transit of Mercury happens only 14 times in the 21st century (2001 to 2100). Read more about the Mercury transit on November 11, 2019.

Bottom line: The Southern Hemisphere enjoys a superb view of Mercury and Venus in October 2019. If you live at northerly latitudes, have binoculars handy!

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Update on the 2nd interstellar visitor

The Hubble Space Telescope captured this image of the 2nd known interstellar object – called comet 2I/Borisov by earthly astronomers – on October 12, 2019, when the object was about 260 million miles (420 million km) from Earth. This object is believed to have arrived here from another planetary system elsewhere in our galaxy. Image via NASA/ESA/D. Jewitt/SpaceTelescope.org.

Astronomers estimate that several interstellar objects – objects originating in other solar systems – pass inside the orbit of Earth each year. By one estimate, 10,000 pass inside the orbit of Neptune on any given day. They all passed unseen, for billions of years, until recently. Astronomers in Hawaii happened upon the first interstellar object – now officially called 1I/’Oumuamua – in late 2017. An amateur astronomer, Gennadiy Borisov, spotted the second one on August 30, 2019, using a 26-inch (0.65-meter) telescope he designed and built himself. This second object was officially named 2I/Borisov by the International Astronomical Union in late September. The “I” stands for interstellar. The “2” means it’s the second such object known to astronomers. It’s still rushing toward its encounter with our sun and will pass closest to our sun – at a distance of about two astronomical units (AU), or about twice the Earth-sun distance – on December 8, 2019.

As it sweeps through our neighborhood of space, astronomers are rushing to study this object. This week (October 14, 2019), the Hubble Space Telescope released the image above of 2I/Borisov. Also, astronomers in Poland published the first peer-reviewed paper about it, discussed below.

New Hubble Space Telescope image of comet 2I/Borisov. The image above was acquired on October 12, 2019, when the object was approximately 260 million miles (420 million km) from Earth. It shows why, unlike ‘Oumuamua, which was hard to distinguish as either definitely asteroid-like or definitely comet-like, the second interstellar object is now confirmed as a comet from another solar system. The Hubble image reveals a very comet-like central concentration of dust around a solid icy nucleus. Astronomer David Jewitt of UCLA, leader of the Hubble team who observed the object, explained in a statement:

Whereas ‘Oumuamua looked like a bare rock, Borisov is really active, more like a normal comet. It’s a puzzle why these two are so different.

Amaya Moro-Martin of the Space Telescope Science Institute in Baltimore, Maryland, added:

Because another star system could be quite different from our own, the comet could have experienced significant changes during its long interstellar journey. Yet its properties are very similar to those of the solar system’s building blocks, and this is very remarkable.

NASA also explained a bit about where these objects come from:

Observations by Hubble and other telescopes have shown that rings and shells of icy debris encircle young stars where planet formation is underway. A gravitational interaction between these comet-like objects and other massive bodies could hurtle them deep into space where they go adrift among the stars.

Future Hubble observations of 2I/Borisov are planned through January 2020, with more being proposed.

Read more about the new Hubble image from SpaceTelescope.org

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

This illustration depicts the trajectory of 2I/Borisov, formerly called C/2019 Q4. Now considered the 2nd known interstellar object – and 1st confirmed comet from another solar system – it will approach no closer to Earth than about 190 million miles (300 million km) before returning again to interstellar space. Image via NASA/JPL-Caltech.

First peer-reviewed paper about 2I/Borisov. Meanwhile, researchers at Jagiellonian University in Kraków in Poland this week published a new study in the peer-reviewed journal Nature Astronomy asserting that – although comet 2I/Borisov appears to be an outcast from another star system – its properties determined so far are “surprisingly familiar.” Researchers Piotr Guzik and Michal Drahus were well prepared for a visit by this second interstellar object, having created a computer program to look for such objects following the earlier visit of ‘Oumuamua. Their program – nicknamed Interstellar Crusher – scanned:

… tirelessly through online data of newly-found comets and asteroids in search of guests from far away. On September 8, 2019, at 04:15 Universal Time, the program issued a red alert and notified the team of a possible new hyperbolic object arriving from interstellar space.

Piotr Guzik explained:

This code was written specifically for this purpose, and we really hoped to receive this message one day. We only didn’t know when.

As it turned out, the second interstellar object had been first spotted by Gennady Borisov a week earlier, although its identity had been unknown at that time. It was only when astronomers around the world began studying the object’s orbit that its interstellar origin was confirmed. Guzik and Drahus, meanwhile, lost no time in scrutinizing images of the object, acquired by telescopes in various parts of the world. Drahus said:

We immediately noticed the familiar coma and tail that were not seen around ‘Oumuamua. This is really cool because it means that our new visitor is one of these mythical and never-before-seen ‘real’ interstellar comets.

In the course of their study of the object, the two researchers found that, like many comets in our own solar system:

… comet Borisov has a dust-dominated morphology, a reddish hue, and that its solid nucleus is about 1 km [.6 mi] in radius.

Guzik commented:

Make of this what you will, but based on these initial characteristics, this object appears indistinguishable from the native solar system comets.

Read more about this study from Jagiellonian University

How do astronomers know that ‘Oumuamua and 2I/Borisov don’t belong in the sun’s family of objects? The answer is the shape of their orbits. This illustration shows a hyperbolic comet orbit. By definition, this sort of orbit means an object will travel through the solar system only once. Image via ESA.

Now that astronomers have published a paper about them, the comet-like characteristics of 2I/Borisov might seem obvious … yet they’re profound. The comet-like nature of 2IBorisov is direct proof – proof we in our lifetimes could reach out and touch, if we had the will and wherewithal to launch a spacecraft to this object fast enough – that the assumptions of astronomers have been correct all along. Nature does, apparently, operate in other solar systems as it does in our solar system. Our sun and its solar system are, indeed, likely very ordinary. Our neighborhood of space is likely just one example among hundreds of billions of similar systems in this star-island we call the Milky Way.

Prior to 2I/Borisov, all catalogued comets have come, NASA said, from:

… either from a ring of icy debris at the periphery of our solar system, called the Kuiper belt, or from the Oort cloud, a shell of icy objects which is thought to be in the outermost regions of our solar system, with its innermost edge at about 2000 times the distance between the Earth and the sun.

Now that astronomers are beginning to spot them, 2I/Borisov and ‘Oumuamua – whose name means “scout” – mark the beginning of what’s likely to be many more discoveries of interstellar objects. As NASA explained:

There may be thousands of such interstellar objects here at any given time; most, however, are too faint to be detected with present-day telescopes.

And, who knows, if we’re lucky we may eventually spot an interstellar object that isn’t a natural object at all. After all, our Voyager spacecraft are now heading outward from our solar system into interstellar space, with their golden records containing images of Earth, greetings in 55 languages, music, and an EEG showing the brain waves of a woman in love.

Read more from NASA about the Voyager golden records.

Click here for mission status of the Voyagers, showing their current distances

The Voyager golden record, carried by both Voyager 1 and Voyager 2. Read more from NASA about the making of it.

Bottom line: The second known interstellar object has been categorized as a comet and officially named 2I/Borisov. The Hubble Space Telescope released an image of it this week, showing it as distinctly comet-like. Astronomers in Poland published the first peer-reviewed paper about it, confirming its comet-like characteristics.

Source: Initial characterization of interstellar comet 2I/Borisov

Via Jagiellonian University

from EarthSky https://ift.tt/31r5CqX

The Hubble Space Telescope captured this image of the 2nd known interstellar object – called comet 2I/Borisov by earthly astronomers – on October 12, 2019, when the object was about 260 million miles (420 million km) from Earth. This object is believed to have arrived here from another planetary system elsewhere in our galaxy. Image via NASA/ESA/D. Jewitt/SpaceTelescope.org.

Astronomers estimate that several interstellar objects – objects originating in other solar systems – pass inside the orbit of Earth each year. By one estimate, 10,000 pass inside the orbit of Neptune on any given day. They all passed unseen, for billions of years, until recently. Astronomers in Hawaii happened upon the first interstellar object – now officially called 1I/’Oumuamua – in late 2017. An amateur astronomer, Gennadiy Borisov, spotted the second one on August 30, 2019, using a 26-inch (0.65-meter) telescope he designed and built himself. This second object was officially named 2I/Borisov by the International Astronomical Union in late September. The “I” stands for interstellar. The “2” means it’s the second such object known to astronomers. It’s still rushing toward its encounter with our sun and will pass closest to our sun – at a distance of about two astronomical units (AU), or about twice the Earth-sun distance – on December 8, 2019.

As it sweeps through our neighborhood of space, astronomers are rushing to study this object. This week (October 14, 2019), the Hubble Space Telescope released the image above of 2I/Borisov. Also, astronomers in Poland published the first peer-reviewed paper about it, discussed below.

New Hubble Space Telescope image of comet 2I/Borisov. The image above was acquired on October 12, 2019, when the object was approximately 260 million miles (420 million km) from Earth. It shows why, unlike ‘Oumuamua, which was hard to distinguish as either definitely asteroid-like or definitely comet-like, the second interstellar object is now confirmed as a comet from another solar system. The Hubble image reveals a very comet-like central concentration of dust around a solid icy nucleus. Astronomer David Jewitt of UCLA, leader of the Hubble team who observed the object, explained in a statement:

Whereas ‘Oumuamua looked like a bare rock, Borisov is really active, more like a normal comet. It’s a puzzle why these two are so different.

Amaya Moro-Martin of the Space Telescope Science Institute in Baltimore, Maryland, added:

Because another star system could be quite different from our own, the comet could have experienced significant changes during its long interstellar journey. Yet its properties are very similar to those of the solar system’s building blocks, and this is very remarkable.

NASA also explained a bit about where these objects come from:

Observations by Hubble and other telescopes have shown that rings and shells of icy debris encircle young stars where planet formation is underway. A gravitational interaction between these comet-like objects and other massive bodies could hurtle them deep into space where they go adrift among the stars.

Future Hubble observations of 2I/Borisov are planned through January 2020, with more being proposed.

Read more about the new Hubble image from SpaceTelescope.org

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

This illustration depicts the trajectory of 2I/Borisov, formerly called C/2019 Q4. Now considered the 2nd known interstellar object – and 1st confirmed comet from another solar system – it will approach no closer to Earth than about 190 million miles (300 million km) before returning again to interstellar space. Image via NASA/JPL-Caltech.

First peer-reviewed paper about 2I/Borisov. Meanwhile, researchers at Jagiellonian University in Kraków in Poland this week published a new study in the peer-reviewed journal Nature Astronomy asserting that – although comet 2I/Borisov appears to be an outcast from another star system – its properties determined so far are “surprisingly familiar.” Researchers Piotr Guzik and Michal Drahus were well prepared for a visit by this second interstellar object, having created a computer program to look for such objects following the earlier visit of ‘Oumuamua. Their program – nicknamed Interstellar Crusher – scanned:

… tirelessly through online data of newly-found comets and asteroids in search of guests from far away. On September 8, 2019, at 04:15 Universal Time, the program issued a red alert and notified the team of a possible new hyperbolic object arriving from interstellar space.

Piotr Guzik explained:

This code was written specifically for this purpose, and we really hoped to receive this message one day. We only didn’t know when.

As it turned out, the second interstellar object had been first spotted by Gennady Borisov a week earlier, although its identity had been unknown at that time. It was only when astronomers around the world began studying the object’s orbit that its interstellar origin was confirmed. Guzik and Drahus, meanwhile, lost no time in scrutinizing images of the object, acquired by telescopes in various parts of the world. Drahus said:

We immediately noticed the familiar coma and tail that were not seen around ‘Oumuamua. This is really cool because it means that our new visitor is one of these mythical and never-before-seen ‘real’ interstellar comets.

In the course of their study of the object, the two researchers found that, like many comets in our own solar system:

… comet Borisov has a dust-dominated morphology, a reddish hue, and that its solid nucleus is about 1 km [.6 mi] in radius.

Guzik commented:

Make of this what you will, but based on these initial characteristics, this object appears indistinguishable from the native solar system comets.

Read more about this study from Jagiellonian University

How do astronomers know that ‘Oumuamua and 2I/Borisov don’t belong in the sun’s family of objects? The answer is the shape of their orbits. This illustration shows a hyperbolic comet orbit. By definition, this sort of orbit means an object will travel through the solar system only once. Image via ESA.

Now that astronomers have published a paper about them, the comet-like characteristics of 2I/Borisov might seem obvious … yet they’re profound. The comet-like nature of 2IBorisov is direct proof – proof we in our lifetimes could reach out and touch, if we had the will and wherewithal to launch a spacecraft to this object fast enough – that the assumptions of astronomers have been correct all along. Nature does, apparently, operate in other solar systems as it does in our solar system. Our sun and its solar system are, indeed, likely very ordinary. Our neighborhood of space is likely just one example among hundreds of billions of similar systems in this star-island we call the Milky Way.

Prior to 2I/Borisov, all catalogued comets have come, NASA said, from:

… either from a ring of icy debris at the periphery of our solar system, called the Kuiper belt, or from the Oort cloud, a shell of icy objects which is thought to be in the outermost regions of our solar system, with its innermost edge at about 2000 times the distance between the Earth and the sun.

Now that astronomers are beginning to spot them, 2I/Borisov and ‘Oumuamua – whose name means “scout” – mark the beginning of what’s likely to be many more discoveries of interstellar objects. As NASA explained:

There may be thousands of such interstellar objects here at any given time; most, however, are too faint to be detected with present-day telescopes.

And, who knows, if we’re lucky we may eventually spot an interstellar object that isn’t a natural object at all. After all, our Voyager spacecraft are now heading outward from our solar system into interstellar space, with their golden records containing images of Earth, greetings in 55 languages, music, and an EEG showing the brain waves of a woman in love.

Read more from NASA about the Voyager golden records.

Click here for mission status of the Voyagers, showing their current distances

The Voyager golden record, carried by both Voyager 1 and Voyager 2. Read more from NASA about the making of it.

Bottom line: The second known interstellar object has been categorized as a comet and officially named 2I/Borisov. The Hubble Space Telescope released an image of it this week, showing it as distinctly comet-like. Astronomers in Poland published the first peer-reviewed paper about it, confirming its comet-like characteristics.

Source: Initial characterization of interstellar comet 2I/Borisov

Via Jagiellonian University

from EarthSky https://ift.tt/31r5CqX

Zoom in on the Ghost Nebula

The video above zooms in on nebula IC 63 — nicknamed the Ghost Nebula — about 550 light-years away. It starts with a view of the night sky as seen from the ground. It then zooms through observations from the Digitized Sky Survey 2, and ends with a view of the nebula obtained with the NASA/ESA Hubble Space Telescope.

The nebula, or space cloud made of gas and dust, known as IC 63, is sometimes called the Ghost Nebula. It’s about 550 light-years from us, in the direction of the constellation Cassiopeia the Queen. It looks ghostlike in telescopic images, such as the one by the Hubble Space Telescope shown below.

Like any respectable ghost, IC 63 is slowly melting away; that is, it’s dissipating due to intense radiation from a nearby unpredictably variable star, Gamma Cassiopeiae, aka Gamma Cas. Did we say nearby? We meant several light-years away.

Yet – even from this distance – Gamma Cas is profoundly affecting the Ghost Nebula.

Hubble Space Telescope view of IC 63, nicknamed the Ghost Nebula. Via NASA/ESA/Hubble.

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NASA explained in a statement:

Gamma Cassiopeiae is a blue-white subgiant variable star that is surrounded by a gaseous disk. This star is 19 times more massive and 65,000 times brighter than our sun. It also rotates at the incredible speed of 1 milllion miles per hour [1.6 million km per hour] – more than 200 times faster than our parent star. This frenzied rotation gives it a squashed appearance. The fast rotation causes eruptions of mass from the star into a surrounding disk. This mass loss is related to the observed brightness variations.

On autumn evenings in the Northern Hemisphere, you’ll easily see the constellation Cassiopeia as an M- or W-shaped star pattern, ascending in the northeast.

The colors in the Ghost Nebula show how the nebula is affected by the powerful radiation from the distant star. NASA said:

The hydrogen within IC 63 is being bombarded with ultraviolet radiation from Gamma Cassiopeiae, causing its electrons to gain energy which they later release as hydrogen-alpha radiation – visible in red in [the Hubble image above].

This hydrogen-alpha radiation makes IC 63 an emission nebula, but we also see blue light in this image. This is light from Gamma Cassiopeiae that has been reflected by dust particles in the nebula, meaning that IC 63 is also a reflection nebula.

This colorful and ghostly nebula is slowly dissipating under the influence of ultraviolet radiation from Gamma Cassiopeiae. However, IC 63 is not the only object under the influence of the mighty star. It is part of a much larger nebulous region surrounding Gamma Cassiopeiae that measures approximately two degrees on the sky — roughly four times as wide as the full moon.

Read more via Hubble Space Telescope

Ground-based view of the sky around the Ghost Nebula. The bright star is Gamma Cassiopeiae. Via ESA/Hubble/NASA/Digitized Sky Survey 2/Davide de Martin.

Bottom line: Zoom-in video, photos, and info about IC 63, the Ghost Nebula, which is being shaped by radiation from the variable star Gamma Cassiopeia.

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

The video above zooms in on nebula IC 63 — nicknamed the Ghost Nebula — about 550 light-years away. It starts with a view of the night sky as seen from the ground. It then zooms through observations from the Digitized Sky Survey 2, and ends with a view of the nebula obtained with the NASA/ESA Hubble Space Telescope.

The nebula, or space cloud made of gas and dust, known as IC 63, is sometimes called the Ghost Nebula. It’s about 550 light-years from us, in the direction of the constellation Cassiopeia the Queen. It looks ghostlike in telescopic images, such as the one by the Hubble Space Telescope shown below.

Like any respectable ghost, IC 63 is slowly melting away; that is, it’s dissipating due to intense radiation from a nearby unpredictably variable star, Gamma Cassiopeiae, aka Gamma Cas. Did we say nearby? We meant several light-years away.

Yet – even from this distance – Gamma Cas is profoundly affecting the Ghost Nebula.

Hubble Space Telescope view of IC 63, nicknamed the Ghost Nebula. Via NASA/ESA/Hubble.

EarthSky’s 2020 lunar calendars are here! Get yours today. They make great gifts. Going fast.

NASA explained in a statement:

Gamma Cassiopeiae is a blue-white subgiant variable star that is surrounded by a gaseous disk. This star is 19 times more massive and 65,000 times brighter than our sun. It also rotates at the incredible speed of 1 milllion miles per hour [1.6 million km per hour] – more than 200 times faster than our parent star. This frenzied rotation gives it a squashed appearance. The fast rotation causes eruptions of mass from the star into a surrounding disk. This mass loss is related to the observed brightness variations.

On autumn evenings in the Northern Hemisphere, you’ll easily see the constellation Cassiopeia as an M- or W-shaped star pattern, ascending in the northeast.

The colors in the Ghost Nebula show how the nebula is affected by the powerful radiation from the distant star. NASA said:

The hydrogen within IC 63 is being bombarded with ultraviolet radiation from Gamma Cassiopeiae, causing its electrons to gain energy which they later release as hydrogen-alpha radiation – visible in red in [the Hubble image above].

This hydrogen-alpha radiation makes IC 63 an emission nebula, but we also see blue light in this image. This is light from Gamma Cassiopeiae that has been reflected by dust particles in the nebula, meaning that IC 63 is also a reflection nebula.

This colorful and ghostly nebula is slowly dissipating under the influence of ultraviolet radiation from Gamma Cassiopeiae. However, IC 63 is not the only object under the influence of the mighty star. It is part of a much larger nebulous region surrounding Gamma Cassiopeiae that measures approximately two degrees on the sky — roughly four times as wide as the full moon.

Read more via Hubble Space Telescope

Ground-based view of the sky around the Ghost Nebula. The bright star is Gamma Cassiopeiae. Via ESA/Hubble/NASA/Digitized Sky Survey 2/Davide de Martin.

Bottom line: Zoom-in video, photos, and info about IC 63, the Ghost Nebula, which is being shaped by radiation from the variable star Gamma Cassiopeia.

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