Tonight, look for a constellation that’s easy to see on the sky’s dome, if your sky is dark enough. Corona Borealis – aka the Northern Crown – is exciting to find. It’s an almost-perfect semicircle of stars. You’ll find this beautiful pattern in the evening sky from now until October.
The constellation Corona Borealis is located more or less along a line between two bright stars, Arcturus in the constellation Boötes the Herdsman and Vega in the constellation Lyra the Harp.
At nightfall and early evening, you’ll see Arcturus fairly high in the east to northeast, noticeable for its brightness and yellow-orange color. Vega will be rather low in the northeast – bright and blue-white in color. The Northern Crown is more or less between these 2 bright stars.
You’ll need a fairly dark sky to see Corona Borealis between Vega and Arcturus. It’s a semicircle of stars – very noticeable.
The brightest star in Corona Borealis is Alphecca, also known as Gemma, sometimes called the Pearl of the Crown. The name Alphecca originated with a description of Corona Borealis as the “broken one,” in reference to the fact that these stars appear in a semi-circle, rather than a full circle. Alphecca is a blue-white star, with an intrinsic luminosity some 60 times that of our sun. It’s located about 75 light-years from Earth.
The C-shaped constellation Corona Borealis shines between the constellations Boötes and Hercules. Constellation chart via IAU.
View at EarthSky Conmmunity Photos. | Dr Ski in Valencia, Philippines caught this photo of Arcturus and its constellation Bootes, next to the Northern Crown, on May 24, 2019. Thanks, Dr Ski!
Bottom line: Look for Corona Borealis – the Northern Crown – between the brilliant stars Arcturus and Vega tonight! This constellation is very noticeable, if you have a dark sky.
Tonight, look for a constellation that’s easy to see on the sky’s dome, if your sky is dark enough. Corona Borealis – aka the Northern Crown – is exciting to find. It’s an almost-perfect semicircle of stars. You’ll find this beautiful pattern in the evening sky from now until October.
The constellation Corona Borealis is located more or less along a line between two bright stars, Arcturus in the constellation Boötes the Herdsman and Vega in the constellation Lyra the Harp.
At nightfall and early evening, you’ll see Arcturus fairly high in the east to northeast, noticeable for its brightness and yellow-orange color. Vega will be rather low in the northeast – bright and blue-white in color. The Northern Crown is more or less between these 2 bright stars.
You’ll need a fairly dark sky to see Corona Borealis between Vega and Arcturus. It’s a semicircle of stars – very noticeable.
The brightest star in Corona Borealis is Alphecca, also known as Gemma, sometimes called the Pearl of the Crown. The name Alphecca originated with a description of Corona Borealis as the “broken one,” in reference to the fact that these stars appear in a semi-circle, rather than a full circle. Alphecca is a blue-white star, with an intrinsic luminosity some 60 times that of our sun. It’s located about 75 light-years from Earth.
The C-shaped constellation Corona Borealis shines between the constellations Boötes and Hercules. Constellation chart via IAU.
View at EarthSky Conmmunity Photos. | Dr Ski in Valencia, Philippines caught this photo of Arcturus and its constellation Bootes, next to the Northern Crown, on May 24, 2019. Thanks, Dr Ski!
Bottom line: Look for Corona Borealis – the Northern Crown – between the brilliant stars Arcturus and Vega tonight! This constellation is very noticeable, if you have a dark sky.
View at EarthSky Community Photos. | Earl Martin in Everett, Washington captured this image of a rare reflection rainbow over Puget Sound on May 5, 2020. Thanks for sharing, Earl!
When he captured this photo, Earl Martin wondered if he’d caught a triple rainbow. But what experts in atmospheric optics call tertiary or quaternary rainbows are exceedingly rare. Read the latest on them – from 2011 – here: First-ever photos of triple and quadruple rainbows
So the photo above isn’t a triple rainbow. But it’s still a rare kind of rainbow, rare enough to cause most people to do a double-take. Earl caught what’s called a reflection rainbow, which can be caused sunlight beaming upwards after reflecting from wet sand or calm water. In this case, the reflection rainbow is coming the water of Puget Sound in the Pacific Northwest, located along the northwestern coast of the U.S. state of Washington.
On his page of explanation for reflection rainbow, Les Cowley of the website Atmospheric Optics has the following diagram, showing exactly how reflection rainbows form.
You can see in this diagram just what’s in Earl’s photo at top, a double rainbow (labeled primary and secondary bows in the diagram above), plus one reflection rainbow. Les wrote of the diagram:
The centers of reflection bows are at the same altitude as the sun – the anthelic point [point on the celestial sphere which lies directly opposite the sun from the observer]. This is the same distance above the horizon as the centers of normal bows are below it at the antisolar point.
The normal bow and its corresponding reflection bow intersect at the horizon.
Reflection bows are usually brightest when the sun is low because then its light is reflected most strongly from water surfaces. The normal and reflection bows draw closer together as the sun gets lower.
The source of the reflected light is usually water behind you, i.e. sunwards. It can be in front of you but then only the base of the reflected bow will be seen.
Thank you, Les, and thank you, Earl!
Bottom line: The photo shows what looks like an ordinary double rainbow with a third rainbow, at an odd angle, in their midst. The third rainbow is the reflection rainbow, reflected from the water in Puget Sound on May 5, 2020.
View at EarthSky Community Photos. | Earl Martin in Everett, Washington captured this image of a rare reflection rainbow over Puget Sound on May 5, 2020. Thanks for sharing, Earl!
When he captured this photo, Earl Martin wondered if he’d caught a triple rainbow. But what experts in atmospheric optics call tertiary or quaternary rainbows are exceedingly rare. Read the latest on them – from 2011 – here: First-ever photos of triple and quadruple rainbows
So the photo above isn’t a triple rainbow. But it’s still a rare kind of rainbow, rare enough to cause most people to do a double-take. Earl caught what’s called a reflection rainbow, which can be caused sunlight beaming upwards after reflecting from wet sand or calm water. In this case, the reflection rainbow is coming the water of Puget Sound in the Pacific Northwest, located along the northwestern coast of the U.S. state of Washington.
On his page of explanation for reflection rainbow, Les Cowley of the website Atmospheric Optics has the following diagram, showing exactly how reflection rainbows form.
You can see in this diagram just what’s in Earl’s photo at top, a double rainbow (labeled primary and secondary bows in the diagram above), plus one reflection rainbow. Les wrote of the diagram:
The centers of reflection bows are at the same altitude as the sun – the anthelic point [point on the celestial sphere which lies directly opposite the sun from the observer]. This is the same distance above the horizon as the centers of normal bows are below it at the antisolar point.
The normal bow and its corresponding reflection bow intersect at the horizon.
Reflection bows are usually brightest when the sun is low because then its light is reflected most strongly from water surfaces. The normal and reflection bows draw closer together as the sun gets lower.
The source of the reflected light is usually water behind you, i.e. sunwards. It can be in front of you but then only the base of the reflected bow will be seen.
Thank you, Les, and thank you, Earl!
Bottom line: The photo shows what looks like an ordinary double rainbow with a third rainbow, at an odd angle, in their midst. The third rainbow is the reflection rainbow, reflected from the water in Puget Sound on May 5, 2020.
The globular cluster Omega Centauri seen from ESO’s La Silla Observatory. Image via Wikimedia Commons.
Having a mass of 5 million suns, Omega Centauri is 10 times more massive than a typical globular cluster. Omega Centauri has a diameter of 230 light-years. It’s a stellar city sparkling with perhaps 10 million stars. Globular clusters generally have stars of similar age and composition. However, studies of Omega Centauri reveal that this cluster has different stellar populations that formed at varying periods of time. It may be that Omega Centauri is a remnant of a small galaxy that merged with the Milky Way.
Spica, the brightest star in the constellation Virgo, serves as your guide star to the Omega Centauri globular star cluster. When Spica is highest up for the night, so is Omega Centauri!
How to see Omega Centauri. Omega Centauri – the Milky Way galaxy’s largest and most luminous globular star cluster – is far to the south on the sky’s dome. It’s visible from the southern half of the United States, or south of 40 degrees north latitude (the latitude of Denver, Colorado). Canadians hasten to remind us that they can spot Omega Centauri from as far north as Point Pelee in Canada (42 degrees latitude). When seeing conditions are just right, they can catch the Omega Cenaturi star cluster skimming along the surface of Lake Erie, they say.
From the Southern Hemisphere, Omega Centauri appears much higher in the sky and is a glorious sight.
If you’re in the Northern Hemisphere and want to spot this cluster, know that Omega Centauri can only be seen at certain times of the year. It’s best seen in the evening sky from the Northern Hemisphere on late April, May and June evenings.
Around mid-May, this wondrous star cluster is highest up and due south around 11 p.m. local daylight saving time.
By mid-June, Omega Centauri is highest up and due south around 10 p.m. local daylight saving time.
Northern Hemisphere residents can see Omega Centauri from January through April as well, but they must be willing to stay up past midnight or to get up before dawn.
Spica, the brightest star in the constellation Virgo, serves as your guide star to Omega Centauri. When Spica and Omega Centauri transit – appear due south and reach the highest point in the sky – they do so in unison. However, Omega Centauri transits about 35 degrees south of (or below) sparkling blue-white Spica. For reference, your fist at arm’s length approximates 10 degrees of sky. Find Spica’s transit time for your sky at this U.S. Naval Observatory page, or follow the arc in the handle of the Big Dipper to find Spica.
Omega Centauri in infrared, via Spitzer Space Telescope/ Wikimedia Commons.
Omega Centauri is a globular, not an open, star cluster. The symmetrical, round appearance of Omega Centauri distinguishes it from clusters such as the Pleiades and Hyades, which are open star clusters.
An open star cluster is a loose gathering of dozens to hundreds of young stars within the disk of the Milky Way galaxy. Open clusters are weakly held together by gravity, and tend to disperse after several hundreds of millions of years.
Globular clusters orbit the Milky Way outside the galactic disk. They harbor tens of thousands to millions of stars. Tightly bound by gravity, globular clusters remain intact after 12 billion years.
Generally, open clusters visible to the unaided eye are hundreds to a few thousand light-years away. In contrast, globular clusters are generally tens of thousands of light-years distant.
At 16,000 to 18,000 light-years, Omega Centauri is one of the few of the galaxy’s 200 or so globular clusters that is visible to the unaided eye. It looks like a faint, fuzzy star, but Omega Centauri’s mere presence testifies to its size and brilliance. Like any globular cluster, Omega Centauri is best appreciated with a telescope.
Omega Centauri’s position is at Right Ascension: 13h 26.8m; Declination: 47 degrees 29′ south
Bottom line: The globular star cluster Omega Centauri is by far the largest globular cluster known, as seen from Earth. It’s about 10 times more massive than a typical globular cluster.
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The globular cluster Omega Centauri seen from ESO’s La Silla Observatory. Image via Wikimedia Commons.
Having a mass of 5 million suns, Omega Centauri is 10 times more massive than a typical globular cluster. Omega Centauri has a diameter of 230 light-years. It’s a stellar city sparkling with perhaps 10 million stars. Globular clusters generally have stars of similar age and composition. However, studies of Omega Centauri reveal that this cluster has different stellar populations that formed at varying periods of time. It may be that Omega Centauri is a remnant of a small galaxy that merged with the Milky Way.
Spica, the brightest star in the constellation Virgo, serves as your guide star to the Omega Centauri globular star cluster. When Spica is highest up for the night, so is Omega Centauri!
How to see Omega Centauri. Omega Centauri – the Milky Way galaxy’s largest and most luminous globular star cluster – is far to the south on the sky’s dome. It’s visible from the southern half of the United States, or south of 40 degrees north latitude (the latitude of Denver, Colorado). Canadians hasten to remind us that they can spot Omega Centauri from as far north as Point Pelee in Canada (42 degrees latitude). When seeing conditions are just right, they can catch the Omega Cenaturi star cluster skimming along the surface of Lake Erie, they say.
From the Southern Hemisphere, Omega Centauri appears much higher in the sky and is a glorious sight.
If you’re in the Northern Hemisphere and want to spot this cluster, know that Omega Centauri can only be seen at certain times of the year. It’s best seen in the evening sky from the Northern Hemisphere on late April, May and June evenings.
Around mid-May, this wondrous star cluster is highest up and due south around 11 p.m. local daylight saving time.
By mid-June, Omega Centauri is highest up and due south around 10 p.m. local daylight saving time.
Northern Hemisphere residents can see Omega Centauri from January through April as well, but they must be willing to stay up past midnight or to get up before dawn.
Spica, the brightest star in the constellation Virgo, serves as your guide star to Omega Centauri. When Spica and Omega Centauri transit – appear due south and reach the highest point in the sky – they do so in unison. However, Omega Centauri transits about 35 degrees south of (or below) sparkling blue-white Spica. For reference, your fist at arm’s length approximates 10 degrees of sky. Find Spica’s transit time for your sky at this U.S. Naval Observatory page, or follow the arc in the handle of the Big Dipper to find Spica.
Omega Centauri in infrared, via Spitzer Space Telescope/ Wikimedia Commons.
Omega Centauri is a globular, not an open, star cluster. The symmetrical, round appearance of Omega Centauri distinguishes it from clusters such as the Pleiades and Hyades, which are open star clusters.
An open star cluster is a loose gathering of dozens to hundreds of young stars within the disk of the Milky Way galaxy. Open clusters are weakly held together by gravity, and tend to disperse after several hundreds of millions of years.
Globular clusters orbit the Milky Way outside the galactic disk. They harbor tens of thousands to millions of stars. Tightly bound by gravity, globular clusters remain intact after 12 billion years.
Generally, open clusters visible to the unaided eye are hundreds to a few thousand light-years away. In contrast, globular clusters are generally tens of thousands of light-years distant.
At 16,000 to 18,000 light-years, Omega Centauri is one of the few of the galaxy’s 200 or so globular clusters that is visible to the unaided eye. It looks like a faint, fuzzy star, but Omega Centauri’s mere presence testifies to its size and brilliance. Like any globular cluster, Omega Centauri is best appreciated with a telescope.
Omega Centauri’s position is at Right Ascension: 13h 26.8m; Declination: 47 degrees 29′ south
Bottom line: The globular star cluster Omega Centauri is by far the largest globular cluster known, as seen from Earth. It’s about 10 times more massive than a typical globular cluster.
The movement of Comet C/2020 F8 (SWAN) through successive all-sky maps as observed with the SWAN instrument on SOHO during the period from April 1 to May 9, 2020. Image via ESA.
Currently crossing the skies above Earth, Comet C/2020 F8 (SWAN) is grazing the northeastern horizon before dawn now and has some potential to become more prominent object by late May or early June. Yet it wasn’t discovered by someone looking up at the night sky. Instead, the person was looking at a computer screen.
Amateur astronomer Michael Mattiazzo from Australia spotted this icy visitor from the outer solar system while inspecting images that had been posted online from the Solar Wind ANisotropies (SWAN) instrument aboard SOHO, the ESA/NASA Solar and Heliospheric Observatory.
SWAN captures images in ultraviolet light, including a specific ultraviolet wavelength called Lyman alpha. This is a wavelength that is characteristically emitted by hydrogen atoms. The instrument’s primary goal is to map changes in the solar wind, the variable flow of charged particles that is continuously released by the sun into interplanetary space. In addition, it has become an effective discoverer of comets, too, because comets are also sources of hydrogen.
In the case of a comet, the hydrogen comes from the water vapor the icy core releases into space when heated by the sun. And there is more, as solar radiation can break water molecules (H2O) into a single hydrogen atom (H) and a hydrogen-oxygen pair (which scientists call a hydroxyl radical, or OH). The result is a cloud of hydrogen that surrounds the comet, giving off a bright spot of Lyman-alpha light that can be spotted in the SWAN maps.
Almost every day, SWAN records a complete map of the sky. These raw sky maps are full of stars, making it difficult to pick out new comets, which may arrive at random from any direction. To make the job easier, successive maps are automatically subtracted from one another, removing the stars and leaving only variable or moving sources visible.
These ‘difference images’ are regularly posted online on the SOHO website, meaning that anyone with internet access can look at these ‘comet tracker’s maps’ and join the search for new comets. To date, 12 of them have been spotted in the SWAN data since 1996, all of them by amateur astronomers, or citizen scientists as they are also known.
In the case of this current comet, Mattiazzo (who has already discovered eight comets using this method) found it by comparing the SWAN maps from several days in early April 2020.
Comet SWAN in all-sky map from SOHO. Image via ESA.
From discovery to observation
Once the comet had been announced, Austrian astrophotographer Gerald Rhemann obtained a beautiful image of it from the desert in Namibia, clearly showing the spherical gas cloud of the comet’s coma and its extended ion tail. When the image was published as Astronomy Picture of the Day (APOD) on April 29, it helped bring the comet to wide scale attention.
Another image, taken a few days later by British astrophotographer Damian Peach using a remote telescope in Chile and also featured as APOD, portrays the impressive comet’s tail as it closed in on Earth. The closest approach is estimated for May 13, at around 85 million km from our planet.
The SWAN team’s comet expert, Michael Combi from the University of Michigan, estimates that by April 15 the comet was ejecting about 1300 kg of water vapor every second, or about 4.4×1028 H2O molecules every second. That is a fast rate of ejection when compared to other comets. Jean-Loup Bertaux, former principal investigator and proposer of the SWAN instrument, said:
This is already three times more than Comet 67P/Churyumov-Gerasimenko at its best, when it was visited by ESA’s Rosetta mission between 2014 and 2016.
Will Comet SWAN become an obvious naked eye object?
The comet’s vigor could be significant for observers on Earth. The more material ejected from the comet, the more sunlight it reflects and the more visible it becomes. The comet has moved from the southern to the northern skies. It has not brightened as expected, based on estimates from last month. However, it could brighten as it approaches its May 27 perihelion, or closest point to the sun – if it survives that long.
Comets are fragile objects, and can often break apart as they approach the sun. In late April, the much anticipated Comet ATLAS suffered this fate, breaking into at least 30 fragments. Comet SWAN is now entering the ‘danger zone’ and – at its closest point to the sun on May 27 – the solar heating will be at its maximum.
It can be extremely difficult to predict the behavior of comets that make such close approaches to the sun, but scientists are hopeful that Comet SWAN will remain bright enough to see as it continues its journey. If the comet survives, stargazers on Earth should look for it near the bright star Capella in the constellation of Auriga, the Charioteer. This is almost certainly the only time the comet will be visible in our lifetimes: estimates are not yet fully precise, but it is clear that the comet’s orbital period is measured in thousands or even millions of years.
SOHO’s 3000th comet, discovered in 2015 by a comet hunter from Thailand. Image via ESA.
Waiting for the 4,000th comet
Although Comet SWAN is only the 12th discovery from that particular instrument, it is the 3,932nd comet discovered by SOHO.
This extraordinary number is thanks to the Large Angle and Spectrometric Coronagraph Experiment (LASCO) instrument, with significant help from members of the public.
Karl Battams is LASCO team comet expert at the US Naval Research Laboratory and lead researcher of the Sungrazer Project. He said:
Almost all of SOHO’s comet discoveries so far have been made by citizen scientists scouring images returned by SOHO’s LASCO instrument.
It’s extremely exciting that our sun-watching observatory has spotted so many comets since its launch in 1995. We are eagerly awaiting, along with comet enthusiasts around the world, for the 4,000th discovery, which might happen real soon.
Bottom line: Currently crossing the skies above Earth, Comet C/2020 F8 (SWAN) is grazing the northeastern horizon before dawn now and has some potential to become more prominent object by late May or early June. Yet it wasn’t discovered by someone looking up at the night sky. Instead, the person was looking at a computer screen.
The movement of Comet C/2020 F8 (SWAN) through successive all-sky maps as observed with the SWAN instrument on SOHO during the period from April 1 to May 9, 2020. Image via ESA.
Currently crossing the skies above Earth, Comet C/2020 F8 (SWAN) is grazing the northeastern horizon before dawn now and has some potential to become more prominent object by late May or early June. Yet it wasn’t discovered by someone looking up at the night sky. Instead, the person was looking at a computer screen.
Amateur astronomer Michael Mattiazzo from Australia spotted this icy visitor from the outer solar system while inspecting images that had been posted online from the Solar Wind ANisotropies (SWAN) instrument aboard SOHO, the ESA/NASA Solar and Heliospheric Observatory.
SWAN captures images in ultraviolet light, including a specific ultraviolet wavelength called Lyman alpha. This is a wavelength that is characteristically emitted by hydrogen atoms. The instrument’s primary goal is to map changes in the solar wind, the variable flow of charged particles that is continuously released by the sun into interplanetary space. In addition, it has become an effective discoverer of comets, too, because comets are also sources of hydrogen.
In the case of a comet, the hydrogen comes from the water vapor the icy core releases into space when heated by the sun. And there is more, as solar radiation can break water molecules (H2O) into a single hydrogen atom (H) and a hydrogen-oxygen pair (which scientists call a hydroxyl radical, or OH). The result is a cloud of hydrogen that surrounds the comet, giving off a bright spot of Lyman-alpha light that can be spotted in the SWAN maps.
Almost every day, SWAN records a complete map of the sky. These raw sky maps are full of stars, making it difficult to pick out new comets, which may arrive at random from any direction. To make the job easier, successive maps are automatically subtracted from one another, removing the stars and leaving only variable or moving sources visible.
These ‘difference images’ are regularly posted online on the SOHO website, meaning that anyone with internet access can look at these ‘comet tracker’s maps’ and join the search for new comets. To date, 12 of them have been spotted in the SWAN data since 1996, all of them by amateur astronomers, or citizen scientists as they are also known.
In the case of this current comet, Mattiazzo (who has already discovered eight comets using this method) found it by comparing the SWAN maps from several days in early April 2020.
Comet SWAN in all-sky map from SOHO. Image via ESA.
From discovery to observation
Once the comet had been announced, Austrian astrophotographer Gerald Rhemann obtained a beautiful image of it from the desert in Namibia, clearly showing the spherical gas cloud of the comet’s coma and its extended ion tail. When the image was published as Astronomy Picture of the Day (APOD) on April 29, it helped bring the comet to wide scale attention.
Another image, taken a few days later by British astrophotographer Damian Peach using a remote telescope in Chile and also featured as APOD, portrays the impressive comet’s tail as it closed in on Earth. The closest approach is estimated for May 13, at around 85 million km from our planet.
The SWAN team’s comet expert, Michael Combi from the University of Michigan, estimates that by April 15 the comet was ejecting about 1300 kg of water vapor every second, or about 4.4×1028 H2O molecules every second. That is a fast rate of ejection when compared to other comets. Jean-Loup Bertaux, former principal investigator and proposer of the SWAN instrument, said:
This is already three times more than Comet 67P/Churyumov-Gerasimenko at its best, when it was visited by ESA’s Rosetta mission between 2014 and 2016.
Will Comet SWAN become an obvious naked eye object?
The comet’s vigor could be significant for observers on Earth. The more material ejected from the comet, the more sunlight it reflects and the more visible it becomes. The comet has moved from the southern to the northern skies. It has not brightened as expected, based on estimates from last month. However, it could brighten as it approaches its May 27 perihelion, or closest point to the sun – if it survives that long.
Comets are fragile objects, and can often break apart as they approach the sun. In late April, the much anticipated Comet ATLAS suffered this fate, breaking into at least 30 fragments. Comet SWAN is now entering the ‘danger zone’ and – at its closest point to the sun on May 27 – the solar heating will be at its maximum.
It can be extremely difficult to predict the behavior of comets that make such close approaches to the sun, but scientists are hopeful that Comet SWAN will remain bright enough to see as it continues its journey. If the comet survives, stargazers on Earth should look for it near the bright star Capella in the constellation of Auriga, the Charioteer. This is almost certainly the only time the comet will be visible in our lifetimes: estimates are not yet fully precise, but it is clear that the comet’s orbital period is measured in thousands or even millions of years.
SOHO’s 3000th comet, discovered in 2015 by a comet hunter from Thailand. Image via ESA.
Waiting for the 4,000th comet
Although Comet SWAN is only the 12th discovery from that particular instrument, it is the 3,932nd comet discovered by SOHO.
This extraordinary number is thanks to the Large Angle and Spectrometric Coronagraph Experiment (LASCO) instrument, with significant help from members of the public.
Karl Battams is LASCO team comet expert at the US Naval Research Laboratory and lead researcher of the Sungrazer Project. He said:
Almost all of SOHO’s comet discoveries so far have been made by citizen scientists scouring images returned by SOHO’s LASCO instrument.
It’s extremely exciting that our sun-watching observatory has spotted so many comets since its launch in 1995. We are eagerly awaiting, along with comet enthusiasts around the world, for the 4,000th discovery, which might happen real soon.
Bottom line: Currently crossing the skies above Earth, Comet C/2020 F8 (SWAN) is grazing the northeastern horizon before dawn now and has some potential to become more prominent object by late May or early June. Yet it wasn’t discovered by someone looking up at the night sky. Instead, the person was looking at a computer screen.
Editor’s note: According to recent press reports, two Asian giant hornets – a species not known to occur in North America – were found in northwest Washington state in late 2019, and a hornet colony was found and eliminated in British Columbia. Now scientists are trying to determine whether more of these large predatory insects are present in the region. Entomologist Akito Kawahara explains why headlines referring to “murder hornets” are misleading.
1. How common are these hornets in Asia, and how much alarm do they cause?
The Asian giant hornet (Vespa mandarinia) is fairly common in many parts of Asia, where it is called the “Giant hornet.” Growing up in Japan, I saw them relatively frequently in the mountains outside of Tokyo.
These insects are large and distinctive, with a characteristic orange head and black-banded orange body. Like any other social wasp, they will defend their nest if the colony is disrupted. But in most cases they will not do anything if people aren’t aggressive toward them.
Giant hornets have longer stingers than a honeybee’s, and hornets do not break off their stingers when they sting. Because hornet stingers can puncture thick clothing, people should avoid hornets and their nests whenever possible.
Giant hornets frequently are attracted to tree sap: I was stung by one when I was looking for butterflies on trees. The sting is painful, but the swelling and pain in most cases subside in a few days.
Just as with honey bee stings, an allergic reaction, or anaphylaxis, can occasionally put people in the hospital. In rare cases, severe reactions can become fatal. But wasp and hornet stings killed less than 13 people a year in 2017 and 2018 in Japan – less than 0.00001% of the national population – in a country where many people spend time in the woods.
If you are allergic to bee and wasp stings, it is best to avoid getting close to these insects and their nests, wear white clothing outdoors (they are attracted to dark colors), and avoid carrying open-top sweet drinks such as sodas in the woods.
Barricade and warning sign in front of Giant hornet nest under a tree stump in Deba, Ritto City, Japan. Image via Greg Peterson/ Flickr
2. Are you surprised that the hornets have appeared in North America?
To some degree, yes. Most likely, a single, fertile queen hornet entered Canada via shipping packaging and created the colony that was discovered in 2019.
It’s easy for invasive species to travel this way. More than 19,000 cargo containers arrive daily at U.S. ports, and inspectors can only do random searches of shipping containers. One estimate suggests that just 2% of shipments are searched for evidence of harmful organisms such as plant pests. Many invasive species are intercepted, but some do get through.
It’s very unlikely that an entire colony of hornets was transferred to North America. Colonies of this hornet are often large, and the hornets would be visible and potentially aggressive if their nest were disturbed.
A genetic test indicated that one of the hornets found in Washington was not related to the Canadian colony, but those results have not been published or peer reviewed. The Giant hornet has not been found in 2020 in either the U.S. or Canada.
Four wasp and hornet species often confused with the giant hornet. Upper left: European hornet (Vespa crabro). Upper right: Common aerial yellowjacket (Dolichovespula arenaria). Lower left: European paper wasp (Polistes dominula). Lower right: Baldfaced hornet (Dolichovespula maculata). Images vie gailhampshire (upper left), Gilles Gonthier (upper right), Judy Gallagher (bottom images)/ Flickr
3. What kind of conditions do these insects need to live?
Giant hornets are fairly common in mountainous regions of Asia, but they’re not often seen in large cities or highly urbanized areas. They usually nest at the base of large trees and inside dead logs. The fact that they can’t tolerate extremely hot or cold temperatures makes it unlikely that they would spread to very hot or cold areas of North America.
If active colonies are discovered in 2020 in the Pacific Northwest, which has a more temperate climate, it’s possible that they could spread there. However, it is unlikely that this would happen quickly, as foraging ranges of Vespa are only about 2,300 feet (700 meters) from their nest.
The key to prevent spread is surveillance. Anyone in the Pacific Northwest should be alert for Giant hornets while they are outdoors this summer and fall.
4. If more hornets are found, could they threaten honeybees and other pollinators?
Possibly. Some media posts have described destruction of honeybee nests by what could have been Giant hornets, but honeybees are not these insects’ only prey. The hornets feed on different kinds of insects, and bring captured dead prey back to their hive to feed to their young.
In Japan, beekeepers surround their hives with wire screen nets to protect them from hornets. North American beekeepers can replicate these with wire netting from local hardware stores.
Many honeybees in Asia have the ability to protect their hive from intruding Giant hornets by scorching them. They wait for a hornet to enter their nest, then mob it by surrounding it completely with their bodies. Each honeybee vibrates its wings, and the combined warming of honey bee bodies raises the temperature in the center of the cluster to 122 degrees F (50 degrees C), killing the hornet. Carbon dioxide levels in the nest also increase during this process, which contributes to the hornet’s death.
Japanese honey bees swarm a Giant hornet, killing it with their body heat.
5. Are news stories about “murder hornets” overreacting?
Yes, very much so. In parts of Japan, people consider these hornets beneficial because they remove pests, such as harmful caterpillars, from crops. They are also thought to contain nutrients, and have been used as ingredients in Japanese food and some strong liquors. Some people believe the hornets’ essence has medicinal benefits.
People who live in Vancouver, Seattle or nearby should certainly take note of what these insects look like. They are 2 inches long or more, with a 3-inch wingspan, and have distinctly orange heads and broad striped orange and black-banded abdomens. That’s different from typical North American hornets, which have yellow or white bodies with black marks.
In the unlikely case that you see a Giant hornet in Washington state, do not try to remove nests yourself or spray hornets with pesticides. Cutting down trees to prevent nesting sites is also unnecessary, and can affect many other kinds of native wildlife, including beneficial insects that are needed for pollination and decomposition. Many native insects are declining globally, and it’s important to make sure these insects are not affected.
Instead, take a photo from a distance and report it to the Washington State Department of Agriculture. Photos are essential to verify that identifications are accurate.
Consider also uploading your images to iNaturalist, which is one of the primary sources for information on tracking wildlife. The images are archived and carry data, such as location, time of observance and the insect’s morphological features, that scientists can use for research.
Editor’s note: According to recent press reports, two Asian giant hornets – a species not known to occur in North America – were found in northwest Washington state in late 2019, and a hornet colony was found and eliminated in British Columbia. Now scientists are trying to determine whether more of these large predatory insects are present in the region. Entomologist Akito Kawahara explains why headlines referring to “murder hornets” are misleading.
1. How common are these hornets in Asia, and how much alarm do they cause?
The Asian giant hornet (Vespa mandarinia) is fairly common in many parts of Asia, where it is called the “Giant hornet.” Growing up in Japan, I saw them relatively frequently in the mountains outside of Tokyo.
These insects are large and distinctive, with a characteristic orange head and black-banded orange body. Like any other social wasp, they will defend their nest if the colony is disrupted. But in most cases they will not do anything if people aren’t aggressive toward them.
Giant hornets have longer stingers than a honeybee’s, and hornets do not break off their stingers when they sting. Because hornet stingers can puncture thick clothing, people should avoid hornets and their nests whenever possible.
Giant hornets frequently are attracted to tree sap: I was stung by one when I was looking for butterflies on trees. The sting is painful, but the swelling and pain in most cases subside in a few days.
Just as with honey bee stings, an allergic reaction, or anaphylaxis, can occasionally put people in the hospital. In rare cases, severe reactions can become fatal. But wasp and hornet stings killed less than 13 people a year in 2017 and 2018 in Japan – less than 0.00001% of the national population – in a country where many people spend time in the woods.
If you are allergic to bee and wasp stings, it is best to avoid getting close to these insects and their nests, wear white clothing outdoors (they are attracted to dark colors), and avoid carrying open-top sweet drinks such as sodas in the woods.
Barricade and warning sign in front of Giant hornet nest under a tree stump in Deba, Ritto City, Japan. Image via Greg Peterson/ Flickr
2. Are you surprised that the hornets have appeared in North America?
To some degree, yes. Most likely, a single, fertile queen hornet entered Canada via shipping packaging and created the colony that was discovered in 2019.
It’s easy for invasive species to travel this way. More than 19,000 cargo containers arrive daily at U.S. ports, and inspectors can only do random searches of shipping containers. One estimate suggests that just 2% of shipments are searched for evidence of harmful organisms such as plant pests. Many invasive species are intercepted, but some do get through.
It’s very unlikely that an entire colony of hornets was transferred to North America. Colonies of this hornet are often large, and the hornets would be visible and potentially aggressive if their nest were disturbed.
A genetic test indicated that one of the hornets found in Washington was not related to the Canadian colony, but those results have not been published or peer reviewed. The Giant hornet has not been found in 2020 in either the U.S. or Canada.
Four wasp and hornet species often confused with the giant hornet. Upper left: European hornet (Vespa crabro). Upper right: Common aerial yellowjacket (Dolichovespula arenaria). Lower left: European paper wasp (Polistes dominula). Lower right: Baldfaced hornet (Dolichovespula maculata). Images vie gailhampshire (upper left), Gilles Gonthier (upper right), Judy Gallagher (bottom images)/ Flickr
3. What kind of conditions do these insects need to live?
Giant hornets are fairly common in mountainous regions of Asia, but they’re not often seen in large cities or highly urbanized areas. They usually nest at the base of large trees and inside dead logs. The fact that they can’t tolerate extremely hot or cold temperatures makes it unlikely that they would spread to very hot or cold areas of North America.
If active colonies are discovered in 2020 in the Pacific Northwest, which has a more temperate climate, it’s possible that they could spread there. However, it is unlikely that this would happen quickly, as foraging ranges of Vespa are only about 2,300 feet (700 meters) from their nest.
The key to prevent spread is surveillance. Anyone in the Pacific Northwest should be alert for Giant hornets while they are outdoors this summer and fall.
4. If more hornets are found, could they threaten honeybees and other pollinators?
Possibly. Some media posts have described destruction of honeybee nests by what could have been Giant hornets, but honeybees are not these insects’ only prey. The hornets feed on different kinds of insects, and bring captured dead prey back to their hive to feed to their young.
In Japan, beekeepers surround their hives with wire screen nets to protect them from hornets. North American beekeepers can replicate these with wire netting from local hardware stores.
Many honeybees in Asia have the ability to protect their hive from intruding Giant hornets by scorching them. They wait for a hornet to enter their nest, then mob it by surrounding it completely with their bodies. Each honeybee vibrates its wings, and the combined warming of honey bee bodies raises the temperature in the center of the cluster to 122 degrees F (50 degrees C), killing the hornet. Carbon dioxide levels in the nest also increase during this process, which contributes to the hornet’s death.
Japanese honey bees swarm a Giant hornet, killing it with their body heat.
5. Are news stories about “murder hornets” overreacting?
Yes, very much so. In parts of Japan, people consider these hornets beneficial because they remove pests, such as harmful caterpillars, from crops. They are also thought to contain nutrients, and have been used as ingredients in Japanese food and some strong liquors. Some people believe the hornets’ essence has medicinal benefits.
People who live in Vancouver, Seattle or nearby should certainly take note of what these insects look like. They are 2 inches long or more, with a 3-inch wingspan, and have distinctly orange heads and broad striped orange and black-banded abdomens. That’s different from typical North American hornets, which have yellow or white bodies with black marks.
In the unlikely case that you see a Giant hornet in Washington state, do not try to remove nests yourself or spray hornets with pesticides. Cutting down trees to prevent nesting sites is also unnecessary, and can affect many other kinds of native wildlife, including beneficial insects that are needed for pollination and decomposition. Many native insects are declining globally, and it’s important to make sure these insects are not affected.
Instead, take a photo from a distance and report it to the Washington State Department of Agriculture. Photos are essential to verify that identifications are accurate.
Consider also uploading your images to iNaturalist, which is one of the primary sources for information on tracking wildlife. The images are archived and carry data, such as location, time of observance and the insect’s morphological features, that scientists can use for research.
Most Blue Moons are not blue in color. This photo of a moon among fast-moving clouds was created using special blue filters. Image via our friend Jv Noriega.
The next Blue Moon will come on October 31, 2020. It’ll be called a Blue Moon because it’ll be the second of two full moons to occur in a single calendar month. The last Blue Moon by this definition of the term happened on March 31, 2018.
There’s another definition for Blue Moon. It can be the third of four full moons in a single season, with a season being between a solstice and equinox. The next seasonal Blue Moon will be August 22, 2021.
In recent years, people have been using the name Blue Moon for these two different sorts of moons: second of two full moons in a calendar month, or third of four full moons in a single season.
Someday, you might see an actual blue-colored moon. Meanwhile, the moon you’ll see on October 31, 2020, likely won’t look blue, and blue-colored moons in photos – like the ones on this page – are usually made using special blue camera filters or in a post-processing program such as PhotoShop.
The Virtual Telescope Project in Rome, Italy, hosted a live viewing of the May 18, 2019, full moon rising above the Rome skyline.
Let’s talk about seasonal Blue Moons first. A year has 12 months, and months – or “moonths” – have lengths more or less based on a single orbit of the moon around Earth. What we call a season – winter, spring, summer, fall – typically lasts three months, and typically has three full moons.
If a season has four full moons, then the third full moon may be called a Blue Moon, according to the old Maine Farmer’s Almanac. There was a Blue Moon by this definition on November 21, 2010, another on August 20-21, 2013, another on May 21, 2016, and another on May 18, 2019. The next will be on August 22, 2021.
Desert Blue Moon from our friend Priya Kumar in Oman, August 2012. Thank you, Priya!
The best-known and most popular definition of Blue Moon is that it describes the second full moon of a calendar month. By this definition, there was a Blue Moon on July 31, 2015, January 31, 2018, and March 31, 2018. The next one will be October 31, 2020.
The time between one full moon and the next is close to the length of a calendar month. So the only time one month can have two full moons is when the first full moon happens in the first few days of the month. This happens every two to three years, so these sorts of Blue Moons come about that often.
Very rarely, a seasonal Blue Moon (third of four full moons in one season) and a monthly Blue Moon (second of two full moons in one calendar month) can occur in the same calendar year. For this to happen, you need 13 full moons between successive December solstices for a seasonal Blue Moon – and, generally, 13 full moons in one calendar year for a monthly Blue Moon.
This will next happen in the year 2048, when a monthly Blue Moon falls on January 31, and a seasonal Blue Moon on August 23.
Then 19 years later, in the year 2067, there will be a monthly Blue Moon on March 30, and a seasonal Blue Moon on November 20. In this instance, there are 13 full moons between successive December solstices – but only 12 full moons in one calendar year and no February 2067 full moon.
Blue moons don’t really look blue in color. Greg Hogan got this shot of a Blue Moon (blue in name only!) on July 31, 2015. He wrote: “Having some fun with the blue moon idea……I blended the same image twice one with a blue tint, and one normal. :) “
The idea of a Blue Moon as the second full moon in a month stemmed from the March 1946 issue of Sky and Telescope magazine, which contained an article called Once in a Blue Moon by James Hugh Pruett. Pruett was referring to the 1937 Maine Farmer’s Almanac, but he inadvertently simplified the definition. He wrote:
Seven times in 19 years there were – and still are – 13 full moons in a year. This gives 11 months with one full moon each and one with two. This second in a month, so I interpret it, was called Blue Moon.
Had James Hugh Pruett looked at the actual date of the 1937 Blue Moon, he would have found that it had occurred August 21, 1937. Also, there were only 12 full moons in 1937. You generally need 13 full moons in one calendar year to have two full moons in one calendar month.
However, that fortuitous oversight gave birth to a new and perfectly understandable definition for Blue Moon.
EarthSky’s Deborah Byrd happened upon a copy of this old 1946 issue of Sky and Telescope in the stacks of the Peridier Library at the University of Texas Astronomy Department in the late 1970s. Afterward, she began using the term Blue Moon to describe the second full moon in a calendar month on the radio. Later, this definition of Blue Moon was also popularized by a book for children by Margot McLoon-Basta and Alice Siegel, called Kids’ World Almanac of Records and Facts, published in New York by World Almanac Publications in 1985. The second-full-moon-in-a-month definition was also used in the board game Trivial Pursuit.
Today, it has become part of folklore. As the folklorist Philip Hiscock wrote in his comprehensive article Once in a Blue Moon:
‘Old folklore’ it is not, but real folklore it is.
This photo was created using special blue filters, too. Image via EarthSky Facebook friend Jv Noriega.
Can a moon be blue in color? Yes, but it’s very rare to see a blue-colored moon. You need unusual sky conditions – certain-sized particles of dust or smoke – to create them.
Blue-colored moons aren’t predictable. So don’t be misled by the photos above. The sorts of moons people commonly call Blue Moons aren’t usually blue.
What most call a Blue Moon isn’t blue in color. It’s only Blue in name. This great moon photo is from EarthSky Facebook friend Rebecca Lacey in Cambridge, Idaho.
Bottom line: A blue-colored moon is rare. But folklore has defined two different kinds of Blue Moons, and moons that are Blue by name are pretty common. The next Blue Moon will come on October 31, 2020. It’ll be called a Blue Moon because it’ll be the second of two full moons in a single calendar month.
Most Blue Moons are not blue in color. This photo of a moon among fast-moving clouds was created using special blue filters. Image via our friend Jv Noriega.
The next Blue Moon will come on October 31, 2020. It’ll be called a Blue Moon because it’ll be the second of two full moons to occur in a single calendar month. The last Blue Moon by this definition of the term happened on March 31, 2018.
There’s another definition for Blue Moon. It can be the third of four full moons in a single season, with a season being between a solstice and equinox. The next seasonal Blue Moon will be August 22, 2021.
In recent years, people have been using the name Blue Moon for these two different sorts of moons: second of two full moons in a calendar month, or third of four full moons in a single season.
Someday, you might see an actual blue-colored moon. Meanwhile, the moon you’ll see on October 31, 2020, likely won’t look blue, and blue-colored moons in photos – like the ones on this page – are usually made using special blue camera filters or in a post-processing program such as PhotoShop.
The Virtual Telescope Project in Rome, Italy, hosted a live viewing of the May 18, 2019, full moon rising above the Rome skyline.
Let’s talk about seasonal Blue Moons first. A year has 12 months, and months – or “moonths” – have lengths more or less based on a single orbit of the moon around Earth. What we call a season – winter, spring, summer, fall – typically lasts three months, and typically has three full moons.
If a season has four full moons, then the third full moon may be called a Blue Moon, according to the old Maine Farmer’s Almanac. There was a Blue Moon by this definition on November 21, 2010, another on August 20-21, 2013, another on May 21, 2016, and another on May 18, 2019. The next will be on August 22, 2021.
Desert Blue Moon from our friend Priya Kumar in Oman, August 2012. Thank you, Priya!
The best-known and most popular definition of Blue Moon is that it describes the second full moon of a calendar month. By this definition, there was a Blue Moon on July 31, 2015, January 31, 2018, and March 31, 2018. The next one will be October 31, 2020.
The time between one full moon and the next is close to the length of a calendar month. So the only time one month can have two full moons is when the first full moon happens in the first few days of the month. This happens every two to three years, so these sorts of Blue Moons come about that often.
Very rarely, a seasonal Blue Moon (third of four full moons in one season) and a monthly Blue Moon (second of two full moons in one calendar month) can occur in the same calendar year. For this to happen, you need 13 full moons between successive December solstices for a seasonal Blue Moon – and, generally, 13 full moons in one calendar year for a monthly Blue Moon.
This will next happen in the year 2048, when a monthly Blue Moon falls on January 31, and a seasonal Blue Moon on August 23.
Then 19 years later, in the year 2067, there will be a monthly Blue Moon on March 30, and a seasonal Blue Moon on November 20. In this instance, there are 13 full moons between successive December solstices – but only 12 full moons in one calendar year and no February 2067 full moon.
Blue moons don’t really look blue in color. Greg Hogan got this shot of a Blue Moon (blue in name only!) on July 31, 2015. He wrote: “Having some fun with the blue moon idea……I blended the same image twice one with a blue tint, and one normal. :) “
The idea of a Blue Moon as the second full moon in a month stemmed from the March 1946 issue of Sky and Telescope magazine, which contained an article called Once in a Blue Moon by James Hugh Pruett. Pruett was referring to the 1937 Maine Farmer’s Almanac, but he inadvertently simplified the definition. He wrote:
Seven times in 19 years there were – and still are – 13 full moons in a year. This gives 11 months with one full moon each and one with two. This second in a month, so I interpret it, was called Blue Moon.
Had James Hugh Pruett looked at the actual date of the 1937 Blue Moon, he would have found that it had occurred August 21, 1937. Also, there were only 12 full moons in 1937. You generally need 13 full moons in one calendar year to have two full moons in one calendar month.
However, that fortuitous oversight gave birth to a new and perfectly understandable definition for Blue Moon.
EarthSky’s Deborah Byrd happened upon a copy of this old 1946 issue of Sky and Telescope in the stacks of the Peridier Library at the University of Texas Astronomy Department in the late 1970s. Afterward, she began using the term Blue Moon to describe the second full moon in a calendar month on the radio. Later, this definition of Blue Moon was also popularized by a book for children by Margot McLoon-Basta and Alice Siegel, called Kids’ World Almanac of Records and Facts, published in New York by World Almanac Publications in 1985. The second-full-moon-in-a-month definition was also used in the board game Trivial Pursuit.
Today, it has become part of folklore. As the folklorist Philip Hiscock wrote in his comprehensive article Once in a Blue Moon:
‘Old folklore’ it is not, but real folklore it is.
This photo was created using special blue filters, too. Image via EarthSky Facebook friend Jv Noriega.
Can a moon be blue in color? Yes, but it’s very rare to see a blue-colored moon. You need unusual sky conditions – certain-sized particles of dust or smoke – to create them.
Blue-colored moons aren’t predictable. So don’t be misled by the photos above. The sorts of moons people commonly call Blue Moons aren’t usually blue.
What most call a Blue Moon isn’t blue in color. It’s only Blue in name. This great moon photo is from EarthSky Facebook friend Rebecca Lacey in Cambridge, Idaho.
Bottom line: A blue-colored moon is rare. But folklore has defined two different kinds of Blue Moons, and moons that are Blue by name are pretty common. The next Blue Moon will come on October 31, 2020. It’ll be called a Blue Moon because it’ll be the second of two full moons in a single calendar month.
A favorite constellation for many, little squarish Corvus the Crow, can be found after sunset at this time of year. It’s not far from Spica, the only bright star in the constellation Virgo. Once you find Spica, you’ll recognize Corvus easily. It’s always near the star Spica on the sky’s dome, recognizable for its compact, boxy shape. Spica is supposed to represent an Ear of Wheat, held by Virgo the Maiden. With a good imagination and a dark-enough sky, you can almost see Corvus as a real crow, pecking toward Spica, trying to snatch the wheat.
And thus the stories of the heavens were born …
You don’t need Corvus to identify the bright star Spica. You can use the Big Dipper for that as shown on the diagram below:
Use the handle of the Big Dipper to locate the stars Arcturus and Spica. Just follow the arc in the Dipper’s handle. And remember the phrase “follow the arc to Arcturus, and drive a spike to Spica.”
After you find Spica, Corvus is easy. It’s right next to the bright star, a small boxy pattern that’s noticeable to the eye. Because Corvus is such an easy and fun constellation to pick out in the sky, there are many legends in skylore about it. A lovely one comes from China, where this grouping of stars was seen as an imperial chariot, riding on the wind. In ancient Israel, and sometimes in Greek mythology, Corvus was said to be a raven, not a crow. The early Greeks saw Corvus as a cupbearer to Apollo, god of the sun. The website Constellation-guide.com explains that Corvus was:
… Apollo’s sacred bird in Greek mythology. According to the myth, the raven originally had white feathers. In one story, Apollo told the bird to watch over Coronis, one of his lovers, who was pregnant at the time.
Coronis gradually lost interest in Apollo and fell in love with a mortal man, Ischys. When the raven reported the affair to Apollo, the god was so enraged that the bird did nothing to stop it that he flung a curse on it, scorching the raven’s feathers. That, the legend goes, is why all ravens are black.
Corvus is a friendly sight in the heavens. Along with all the stars, Corvus’s stars will be found a bit farther west at nightfall in the coming weeks and months as Earth moves around the sun. Check it out now and watch for it in the next few months.
The bright star Spica – near Corvus on our sky’s dome – will always be there to guide your eye.
View at EarthSky Community Photos. | Dr Ski in Valencia, Philippines wrote: “Corvus (the Crow) and Crux (the Southern Cross) are at the same right ascension on the celestial sphere. Meaning, they transit the meridian at the same time (approximately 8:30 p.m. local time or 9:30 p.m. local daylight saving time). If you reside in mid-northern latitudes … look for the familiar polygon of Corvus at this time. Then extrapolate a line approximately 40° down to get an idea of how far below your horizon the Southern Cross is.” If you’re further south, of course, as Dr Ski is … just look!
Bottom line: Use the star Spica to introduce yourself to the constellation Corvus the Crow.
A favorite constellation for many, little squarish Corvus the Crow, can be found after sunset at this time of year. It’s not far from Spica, the only bright star in the constellation Virgo. Once you find Spica, you’ll recognize Corvus easily. It’s always near the star Spica on the sky’s dome, recognizable for its compact, boxy shape. Spica is supposed to represent an Ear of Wheat, held by Virgo the Maiden. With a good imagination and a dark-enough sky, you can almost see Corvus as a real crow, pecking toward Spica, trying to snatch the wheat.
And thus the stories of the heavens were born …
You don’t need Corvus to identify the bright star Spica. You can use the Big Dipper for that as shown on the diagram below:
Use the handle of the Big Dipper to locate the stars Arcturus and Spica. Just follow the arc in the Dipper’s handle. And remember the phrase “follow the arc to Arcturus, and drive a spike to Spica.”
After you find Spica, Corvus is easy. It’s right next to the bright star, a small boxy pattern that’s noticeable to the eye. Because Corvus is such an easy and fun constellation to pick out in the sky, there are many legends in skylore about it. A lovely one comes from China, where this grouping of stars was seen as an imperial chariot, riding on the wind. In ancient Israel, and sometimes in Greek mythology, Corvus was said to be a raven, not a crow. The early Greeks saw Corvus as a cupbearer to Apollo, god of the sun. The website Constellation-guide.com explains that Corvus was:
… Apollo’s sacred bird in Greek mythology. According to the myth, the raven originally had white feathers. In one story, Apollo told the bird to watch over Coronis, one of his lovers, who was pregnant at the time.
Coronis gradually lost interest in Apollo and fell in love with a mortal man, Ischys. When the raven reported the affair to Apollo, the god was so enraged that the bird did nothing to stop it that he flung a curse on it, scorching the raven’s feathers. That, the legend goes, is why all ravens are black.
Corvus is a friendly sight in the heavens. Along with all the stars, Corvus’s stars will be found a bit farther west at nightfall in the coming weeks and months as Earth moves around the sun. Check it out now and watch for it in the next few months.
The bright star Spica – near Corvus on our sky’s dome – will always be there to guide your eye.
View at EarthSky Community Photos. | Dr Ski in Valencia, Philippines wrote: “Corvus (the Crow) and Crux (the Southern Cross) are at the same right ascension on the celestial sphere. Meaning, they transit the meridian at the same time (approximately 8:30 p.m. local time or 9:30 p.m. local daylight saving time). If you reside in mid-northern latitudes … look for the familiar polygon of Corvus at this time. Then extrapolate a line approximately 40° down to get an idea of how far below your horizon the Southern Cross is.” If you’re further south, of course, as Dr Ski is … just look!
Bottom line: Use the star Spica to introduce yourself to the constellation Corvus the Crow.
