Tonight’s Sky

The Greater Hazleton Area Astronomical Society

Moon and Gemini stars on April 1

Moon in Gemini.

On April 1, 2020, you’ll find the moon at or near its half-lit first quarter phase and in the vicinity of Castor and Pollux, the two brightest stars in the constellation Gemini the Twins. And there’s another bright star on the other side of the moon on April 12. It’s Procyon, the brightest in the constellation Canis Minor the Lesser Dog. Procyon would be hard to pick out without the help of tonight’s moon, or a good constellation chart. On the other hand, Castor and Pollux are extremely noticeable in the night sky. No other two such bright stars appear so close together.

Regardless of the seeming connection between these two stars, Castor and Pollux aren’t close together in space. They just happen to reside along the same line of sight from Earth.

Both Castor and Pollux are bright stars, and they’ve been known as Twins for centuries at least. But they don’t really look alike. Pollux is golden in color, and Castor is pure white. If you have binoculars, they’ll help you to more easily distinguish the color contrast between Castor and Pollux.

Also, Castor and Pollux are different kinds of stars. Castor is a hot, white-colored star that is well known for being a multiple system. It consists of three pairs of binary stars, that is, six stars bound together in an intricate gravitational dance. Pollux is a cool and bloated orange-colored star, said to be the closest giant star to Earth. A massive star like our sun swells up into a giant in its old age. But astronomers assure us that our sun won’t become a gain for another 5 billion years or so.

Yesterday – March 31, 2020 – the moon crossed the ecliptic (Earth’s orbital plane) at its ascending node at 16:51 Universal Time. Then less than one day later, the moon reaches its first quarter phase on April 1, at 10:21 UTC.

The moon will remain north of the ecliptic (Earth’s orbital plane) until the moon crosses its ascending node on April 13, 2020, at 2:58 UTC. Then the moon will stay south of the ecliptic until it crosses the ecliptic on April 27, at 11:52 UTC.

The sun, on the other hand, passes in front of Gemini for one month each year, from about June 21 to July 20.

Sun tiny like a BB, Pollux like a baseball, Arcturus like a basketball.

You can see the comparative size of the star Pollux and our sun in this image, as well as some other stars. Pollux is a giant star by virtue of its age. Many stars – including our sun – will swell to the giant stage as they age.

In many cultures, Castor and Pollux were seen as twin stars, usually as heroes. Many old sky myths invoke the idea of twins to explain their proximity on the sky’s dome.

Diagram of stars.

If you have a dark sky, notice that 2 nearly parallel streams of stars extend from Castor and Pollux. These stars likely reinforced the idea of twins, in various cultures around the world. Every December, the Geminid meteor shower radiates from near star Castor in Gemini.

In Greek and Roman mythology, Castor and Pollux were the twin sons of Jupiter and Leda and brothers of Helen of Troy. They sailed with Jason as two of his Argonauts.

Pollux, represented by the brighter star, was immortal, but his brother Castor was not. When Castor was killed in a fight, Jupiter wanted the two to remain together, so he decreed that they each should spend some time in the underworld and some time in the heavens. This is a fanciful way of explaining why the constellation is above the horizon for part of each day and below the horizon for the rest. Castor and Pollux are sometimes said to represent brotherly love.

Meanwhile, in China, these two stars were associated with water, as part of constellations representing rivers. They were sometimes also seen as the complementary elements of yin and yang.

Antique etching of boy twins with stars marked.

Castor and Pollux mark the starry eyes of the Gemini Twins. Image via Wikipedia.

Because Gemini is a constellation of the zodiac, the sun passes in front of this constellation for about a month each year, from about June 21 to July 20.

Bottom line: The moon is near the stars Castor and Pollux in the constellation Gemini the Twins on April 1, 2020. These stars represent twins in many cultures.

Venus and the Pleiades cluster after sunset April 2, 2020.

Although the planet Venus has a conjunction with the Pleiades star cluster every year, the best Venus-Pleiades conjunctions only come in early April and recur in cycles of 8 years. Watch on April 2, 3 and 4, 2020, as Venus grazes past this beautiful cluster. On the middle date – April 3, 2020 – Venus passes a scant 1/4 degree south of Alcyone, the brightest star in the Pleiades star cluster. (For reference, the moon’s angular diameter spans about 1/2 degree.)

What’s more, Venus will be at an near-maximum elongation of 46 degrees east of the setting sun. It is indeed a big treat to witness a super-close conjunction of Venus and the Pleiades cluster, and at the same time, have Venus showcase such a favorable elongation from the sun.

For instance, let’s consider last year’s and next year’s Venus-Pleiades conjunctions. Last year, on June 9, 2019, Venus was 5 degrees south of Alcyone but was only 18 degrees west of the rising sun (in the morning sky). Next year, on May 9, 2021, Venus will pass about 4 degrees to the south of Alcyone, but at an elongation of only some 11 degrees east of the setting sun.

It just doesn’t get any better than right now for catching a Venus-Pleiades conjunction. The last good opportunity happened on April 3, 2012, and will next take place on April 4, 2028.

Photo of the Venus-Pleiades conjunction on April 3, 2012.

Think photo opportunity! Eight years ago, a similarly favorable conjunction of Venus and the Pleiades cluster occurred on April 3, 2012. Photo via the eclipse master, Fred Espenak.

Soon after sunset, in the deepening evening twilight, seek out the brightest “star” in your western sky. It’s not really a star at all but the planet Venus. This world ranks the third-brightest celestial object to light up the heavens, after the sun and moon. Given clear skies, you simply can’t miss Venus beaming away at evening dusk. As dusk gives way to darkness, seek for the dipper-shaped Pleiades cluster near Venus on the great dome of sky with either the eye alone or an optical aid.

As seen from North America, we’ll see Venus to the west (below) the Pleiades cluster on April 2, and to the east (above) the Pleiades on April 4. The actual conjunction takes place on April 3, 2020. But no matter where you live worldwide, watch for Venus to move past the dipper-shape Pleiades cluster these next several evenings.

Venus, Pleiades couple up on April 2, 3 and 4

Venus and the Pleiades cluster after sunset April 2, 2020.

Venus and the Pleiades star cluster as seen from mid-northern latitudes in North America on April 2, 2020.

Remember to bring along binoculars, if you have them, because the moonlight might make it difficult to see this magnificent cluster with the eye alone. In a dark sky, however, the Pleiades cluster is quite easy to see with no optical aid.

Conjunctions between Venus and the Pleiades can only happen somewhere between early April and early July. As we mentioned before, a Venus-Pleiades conjunction happens every year, but these super-close conjunctions only come in early April in cycles of 8 years (every other leap year).

Moon and Regulus, the brightest star in the constellation Leo the lion, light up the night sky on April 4, 2020.

Also, on or near April 4, 2020, watch for the bright waxing gibbous moon to pair up with Regulus, the brightest star in the constellation Leo the Lion.

Because Venus orbits the sun 13 times in about the same time period that Earth orbits the sun 8 times, we find similar Venus-Pleiades conjunctions taking place on or near the same date every 8 years. We list these early April Venus-Alcyone conjunctions for the 21st century (2001 to 2100):

April Venus-Pleiades conjunctions in 21st century (2001 to 2100)

2004 April 3: Venus passes 0.55 degrees south of Alcyone
2012 April 3: Venus passes 0.42 degrees south of Alcyone
2020 April 3: Venus passes 0.27 degrees south of Alcyone
2028 April 4: Venus passes 0.10 degrees south of Alcyone
2036 April 4: Venus passes 0.07 degrees north of Alcyone
2044 April 5: Venus passes 0.25 degrees north of Alcyone
2052 April 5: Venus passes 0.45 degrees north of Alcyone
2060 April 6: Venus passes 0.67 degrees north of Alcyone
2068 April 7: Venus passes 0.92 degrees north of Alcyone
2076 April 9: Venus passes 1.18 degrees north of Alcyone
2084 April 11: Venus passes 1.50 degrees north of Alcyone
2092 April 16: Venus passes 1.87 degrees north of Alcyone
2100 April: No April conjunction (conjunction on 2100 July 6: Venus passes 7.93 degrees south of Alcyone)

Source: More Mathematical Astronomy Morsels by Jean Meeus (pages 271-276)

Generally, Venus passes to the south of Alcyone at conjunction. Rarely, Venus can pass to the north of the Pleiades’ brightest star. Venus last passed to the north of Alcyone on May 1, 1849, and will next do so on April 4, 2036. Venus will also swing north of Alcyone in April 2044, 2052, 2060, 2068, 2076,2084 and 2092. After the year 2092, Venus will pass to the south of Alcyone for nearly another two centuries. Venus won’t sweep north of Alcyone after 2092 until the conjunction of April 9, 2279.

So, while the opportunity presents itself, watch for the close pairing of the planet Venus with the Pleiades star cluster on April 2, 3 and 4, 2020!

Follow the arc to Arcturus, drive a spike to Spica  April 5

Sky chart of the Big Dipper, Arcturus and Spica

Follow the arc to Arcturus, and drive a spike to Spica. Scouts learn this phrase. Grandparents teach it to kids. It was one of the first sky tools I learned to use in astronomy.

Although a bright moon lights up the sky these next several nights, these stars should be bright enough to withstand the onslaught of moonlight. After all, Spica serves as a perfect example of a 1st-magnitude star, whereas Arcturus beams brighter yet, shining one magnitude (2 1/2 times) brighter than Spica.

April full moon swings in between the two brilliant springtime stars, Arcturus and Spica.

The upcoming April full moon swings in between the two bright springtime stars, Arcturus and Spica.

Follow the arc to Arcturus. Find the Big Dipper asterism in the northeastern sky in the evening sky this month, maybe around 9 p.m. It’s very easy to see, a large noticeable dipper-shaped pattern in the northeast. Once you see the Big Dipper, notice that it has two parts: a bowl and a handle. Then, with your mind’s eye, extend the natural curve in the Dipper’s handle until you come to a bright orange star: follow the arc to Arcturus.

Arcturus is the brightest star in the constellation Boötes the Herdsman. This star is known in skylore as the Bear Guard.

Modern astronomers know Arcturus as a giant star with an estimated distance of 37 light-years.

Drive a spike to Spica. Once you’ve followed the curve of the Big Dipper’s handle to the star Arcturus, you’re on your way to finding the bright, blue-white star Spica. Just extend that same curve on the sky’s dome.

Spica is the brightest light in Virgo the Maiden, a large, rambling constellation. The star and its constellation were sometimes associated with the Greek goddess of the harvest, Ceres. Spica is from the Latin word for ear, and the general connotation is that this star name refers to an ear of wheat, held by the goddess.

Today we know Spica as a tight double star. The two stars are indistinguishable from a single point of light via ordinary telescopes. Their dual nature was revealed only by analysis of the light from this system via a spectroscope, or instrument that splits light into its component colors. Both stars in the Spica binary system are larger and hotter than our sun. Their diameters are estimated to be 7.8 and 4 times the sun’s diameter, and, taken together, they’re more than 2,000 times brighter than the sun!

Separated by just less than 11 million miles (18 million km), Spica’s two stars orbit a common center of gravity in only four days.

Diagram of Big Dipper with arrows to Arcturus and Spica.

On springtime evenings in the Northern Hemisphere, extend the handle of the Big Dipper to arc to Arcturus, spike Spica and slide into the constellation Corvus the Crow. We sometimes call this extended arc the spring semicircle.

Bottom line: Remember … follow the arc to Arcturus and drive a spike to Spica!

Year’s biggest supermoon on night of April 7-8

Above: Trish Minogue Collins’ photo of last’s year’s biggest supermoon on February 19, 2019, as the rising moon came up behind the Stargazer sculpture in a field at Manorville, New York.

In North America, we often call the April full moon the Pink Moon, Grass Moon or Egg Moon. This year, in 2020, this April full moon also presents the closest (and thereby the largest) supermoon of the year. That’s because this full moon more closely coincides with lunar perigee – the moon’s closest point to Earth in its monthly obit – than any other full moon in the year 2020.

We give the distances (as measured between the centers of the moon and Earth) for the the April 2020 lunar perigee and full moon:

April lunar perigee (221,773 miles or 356,909 km): April 7, 2020, at 18:08 UTC

April full moon (221,851 miles or 357,035 km): April 8, 2020, at 2:35 UTC

The moon comes closest to the Earth for the entire year when it reaches perigee on April 7, 2020, at 18:08 UTC. Of this year’s 13 lunar perigees, this is one of only two lunar perigees that come closer than 357,000 km (221,830 miles). The other close lunar perigee (356,912 km or 221,775 miles) falls on October 16, 2020, approximately 3 1/2 hours after the October 16 new moon.

By the way, that bright star near the moon is Spica, the constellation Virgo’s one and only 1st-magnitude star. April full moons always take place in front of the constellation Virgo the Maiden, to signal the arrival of spring in the Northern Hemisphere and autumn in the Southern Hemisphere. This April full moon is the first of the season’s three full moons to fall in between the March equinox and the June solstice.

Click on Heavens-Above to find out the moon’s position in front of the constellations of the zodiac

April full moon swings in between the two brilliant springtime stars, Arcturus and Spica.

The April full moon swings in between the Northern Hemisphere’s two bright springtime stars, Arcturus and Spica. In the Southern Hemisphere, these two brilliant stars are fixtures of their autumn season.

The moon will appear plenty full to the eye for these next few evenings. Astronomically speaking, though, the moon is said to be full at a well-defined instant: when the moon is 180 degrees opposite the sun in ecliptic longitude. This full moon instant comes on April 8, at 2:35 UTC. (at United States’ time zones, the moon turns precisely full on the evening of April 7, at 10:35 p.m. EDT, 9:35 p.m. CDT, 8:35 p.m. MDT, 7:35 p.m. PDT, 6:35 p.m Alaskan Time and 4:35 p.m. Hawaiian Time.

In other words, the moon reaches its full phase when the moon-sun elongation equals 180 degrees. Click on The Moon Tonight to find out the present moon-sun elongation, remembering that a positive number depicts an waxing moon and a negative number a waning moon.

This April full moon showcases the biggest and closest full moon of 2020. That’s because, in the year 2020, this April full moon is the one that most closely aligns with lunar perigee. Amazingly enough, 14 returns to full moon almost exactly equal 15 returns to lunar perigee. The mean lunar month (as measured from full moon to full moon) equals 29.53059 days whereas the mean anomalistic month (as measured from perigee to perigee) equals 27.55455 days.

Hence:

14 lunar months (14 returns to perigee): 14 x 29.53059 days = 413.43 days

15 anomalistic months (15 returns to perigee): 15 x 27.55455 days = 413.32 days

This 413-day period of time is the equivalent of about one year, one month and 18 days. Therefore, next year’s biggest supermoon will come on May 26, 2021,to showcase next year’s closest alignment between full moon and lunar perigee:

May 2021 lunar perigee (222,022 miles or 357,310 km): May 26, 2021, at 1:52 UTC

May 2021 full moon (222,116 miles or 357,461 km): May 26, 2021, at 11:14 UTC

But this year, the year’s biggest supermoon comes with the April 2020 full moon. Watch for the biggest full moon of the year to shine all night long as it beams in the east after sunset April 7, climbs highest up for the night around midnight, and sets in the west around sunrise April 8.

Seek a daytime moon after sunrise April 9, 2020

Daytime moon.

Avove photo: Buddy Puckhaper in Charleston, South Carolina, contributed the image at top of a daytime moon.

The April 2020 full moon – the closest and largest supermoon of the year – recently lit up the night sky all night long, from dusk till dawn. Right now, however, the moon is now displaying a waning gibbous phase, so it rising in the east well after sunset. But it is also setting in the west after sunrise. Starting around April 10, 2020, you’ll find the waning gibbous moon low in the west at sunrise.

For the mainland United States, the moon on April 9 rises in the east roughly two hours after sunset. Then, on April 10, the moon will set in the west roughly two hours after sunrise. Thus the mornings of April 11, 12 and 13, after sunrise, present a good time to catch a daytime moon over your western horizon. Woot!

View the moon in your eastern sky before going to bed this week. From mid-northern latitudes, it’ll be ascending in the east about 1 1/4 hours later each evening, and setting in the west about 3/4 hour later each morning. These next several days, look for the moon low in your western sky right after sunrise. Day by day, the lighted portion of the waning gibbous moon will shrink. The half-lit last quarter moon will come on April 14, 2020.

The moon is up in the daytime much of the time. But, because it’s pale against the blue sky, it’s not as noticeable as the moon at night. However, there are certain times of the month when the daytime moon is more noticeable, and the coming week presents one of those windows.

Enormous, faint moon behind radio tower with lots of antennas on it.

You’ll often miss the moon during the day because it’s so pale against the blue daytime sky. Look closely this week, especially in the hours after sunrise. Look west! You’ll see it. Our friend Jenney Disimon in Sabah, North Borneo, caught this daytime moon on January 4, 2018.

Why is the daytime moon most noticeable now? The moon is up during the day half the time. It must be, since it orbits around the whole Earth once a month. A crescent moon is hard to see, though, because it’s so near the sun in the sky. At the vicinity of last quarter moon about a week from now, you might have to crane your neck, looking up, to notice it after sunrise.

This week’s moon is noticeable simply because the moon is still showing us most of its lighted face; it appears large in our sky. Also, in the hours after sunrise, the moon is fairly near the western horizon, so people driving to work or school might catch sight of it.

Starting tomorrow, on April 10, 2020, look for a daytime moon in your western sky after sunrise!

Nearly full gibbous moon against blue sky.

Daytime moon seen on December 18, 2010. Image by Brian Pate. Used with permission.

Bottom line: The moon is now in a waning gibbous phase. Beginning Friday morning, shortly after sunrise, you’ll see it floating pale and beautiful against a blue sky. Look west!

Zodiacal light juts upward to Taurus April 10, 2020

Zodiacal light and Venus after dusk in April 2020.

The mysterious zodiacal light is often visible after dusk or before dawn from the tropical regions of the world. But at temperate latitudes in either the Northern or Southern Hemisphere, your best chance of catching the zodiacal light in the evening sky is in late winter and early spring – or for the few months centered on the spring equinox. From northerly latitudes, seek for the zodiacal light in your western sky as dusk gives way to darkness. If you catch it, you’ll see the zodiacal light jutting upward to the constellation Taurus. In April 2020, we’re especially fortunate to have the blazing planet Venus in front of the constellation Taurus the Bull.

Since the recent March equinox is the Northern Hemisphere’s spring equinox, right now is the right time for northerners to spot the zodiacal light in the western sky after all traces of evening twilight have disappeared. Look westward, in the direction of sunset, some 80 to 120 minutes after sundown.

Zodiacal light photo by Noriaki Tanaka, taken on March 23, 2014. Look closely and you might see the constellation Orion to the left of center. The tip of the cone brushes against the Pleiades star cluster. The bright object to the upper left is the planet Jupiter, when it was in front of the constellation Gemini. In 2016, Jupiter shines in front of the constellation Leo.

Zodiacal light photo by Noriaki Tanaka, taken on March 23, 2014. Look closely and you might see the constellation Orion to the left of center. The tip of the cone brushes against the Pleiades star cluster. The bright object to the upper left is the planet Jupiter, when it was in front of the constellation Gemini. In 2016, Jupiter shines in front of the constellation Leo.

From the Southern Hemisphere … your best chance to spot the zodiacal light is in the morning sky now. Look for it in the east before sunup if you live at southerly temperate latitudes – or better yet, wait until the moon wanes to a smaller crescent – and finally exits the morning sky. The zodiacal light with a waning crescent moon in its midst can be a lovely sight!

Back to the Northern Hemisphere’s evening view … Taurus is a constellation of the zodiac, so during a Northern Hemisphere spring, northerners can use Taurus’ two most prominent signposts – the star Aldebaran and the Pleiades star cluster – to help guide you to the zodiacal light in the western sky. And this year, in 2020, we can use the dazzling planet Venus to locate the constellation Taurus!

Because the zodiacal light juts upward from the horizon and streams through the constellations of the zodiac, Taurus serves as your faithful guide to this elusive, glowing pyramid during a Northern Hemisphere spring.

Zodiacal light is visible to our eye because it is composed of interplanetary dust particles that reflect the light of the sun. Because these dust particles circle the sun in nearly the same plane that Earth does, the zodiacal light is always seen running astride the ecliptic – Earth’s orbital plane projected onto the constellations of the zodiac.

So, if you live at northerly latitudes, look for the zodiacal light to point in the direction of Taurus some 80 to 120 minutes after sunset.

Bottom line: For some weeks before and after the March equinox, the glowing pyramid of light known as the zodiacal light is best seen in the west after sunset from the Northern Hemisphere, and the east before dawn from the Southern Hemisphere.

Use the Big Dipper to find the Little Dipper April 11

So you say you can find the Big Dipper, but not the Little Dipper? This post is for you. Here’s the view northward on April evenings. At present the Big Dipper is high in the north during the evening hours. Notice the two outer stars in the bowl of the Big Dipper. These two stars – called Duhbe and Merak – always point to Polaris, the North Star. Find Polaris, and you can find the Little Dipper.

Polaris is special because Earth’s northern axis nearly points to its location in the sky. It’s the star around which the entire northern sky appears to turn.

Polaris is also fun to locate for another reason. It’s part of a famous – though elusive – star pattern, known as the Little Dipper.

So here it is! The Little Dipper! The North Star, Polaris, marks the end of its handle.

Photo sky view showing lines between stars of Big Dipper and arrow pointing to Polaris.

View larger. | No matter where you see the Big Dipper, the two outer stars in its bowl point to Polaris. In this shot, Tom Wildoner caught the Big Dipper and Polaris at around 3:30 a.m. in July 2013. Thanks, Tom!

By the way, Polaris is less than a degree away from the true north celestial pole on the sky’s dome now. It’ll be closest to true north – less than half a degree away – in the year 2102. The change is due to a motion of Earth called “precession,” which causes Earth’s axis to trace out a circle among the stars every 26,000 years.

By the way, thousands of years ago, Polaris was an ordinary star in the northern sky, known to the Greeks by the name Phoenice.

Other ordinary stars in the northern sky now – Kochab and Pherkad, the two outermost stars in the bowl of the Little Dipper (see chart below) – have had the honor of being pole stars.

Kochab and Pherkad served as twin pole stars from about 1500 B.C. to about 500 B.C.

They’re still sometimes called the Guardians of the Pole.

Kochab is located about 126 light-years away. Pherkad is more distant, at about 480 light-years by some estimates. Meanwhile, Polaris is a bit more than 400 light-years away.

Diagram of Big and Little Dippers with star names.

Kochab and Pherkad are the 2 outermost stars in the bowl of the Little Dipper.

Bottom line: The Big Dipper is usually pretty easy to find, but the Little Dipper is less easy. This post tells you how to use the Big Dipper to find Polaris and the Little Dipper, plus how to recognize the stars Kochab and Pherkad.

Star-hop to the Coma star cluster April 12, 2020

Our chart at the top of this post shows the constellation Leo the Lion highest up for the night at roughly 9 p.m. local time (10 p.m. local daylight saving time). That’s the time on your clock no matter where you are on the globe.

Long ago, the Coma star cluster represented the Lion’s tufted tail. It is a beautiful cluster, well worth taking the time to pick out in the night sky. You can see Leo from the suburbs, but you’ll need a dark sky to find the cluster. In mid-evening now, as seen from mid-northern latitudes in the Northern Hemisphere, the constellation of the Lion will be high in the southern sky. You’ll see the Lion at nightfall, too, though more in the south-southeastern portion of sky.

Diagram of Big Dipper with arrows to Polaris and Leo.

An imaginary line drawn between the pointer stars in the Big Dipper – the two outer stars in the Dipper’s bowl – points in one direction toward Polaris, the North Star, and in the opposite direction toward Leo.

We’ll talk more about the star cluster shortly, but first here’s how to spot Leo. Notice the chart above. A line between the two outer stars in the Bowl of the Big Dipper always points toward Leo. Two distinctive star patterns make the Lion fairly easy to identify. Leo’s brightest star – the sparkling blue-white gem Regulus – marks the bottom of a backward question mark of stars known as The Sickle. A triangle of stars highlights the Lion’s hindquarters and tail. If you see a Lion in this pattern of stars, the Sickle outlines the Lion’s mane. The triangle, meanwhile, marks the back side of Leo. Denebola, the name of the outermost star in this rear triangle of Leo, is an Arabic term meaning the Lion’s Tail.

Line from Regulus to Coma open star cluster.

EarthSky Facebook friend Zhean Peter Nacionales in the Philippines captured this view of the Coma star cluster in April 2013. He wrote, “I learned at the EarthSky page to star-hop from Leo to the Coma star cluster, so I packed up my camera and tripod. It was worth it. I definitely saw this star cluster.” Thank you, Zhean!

Now let’s try star-hopping from Leo the Lion to the Coma star cluster. Nowadays, this part of the sky belongs to another constellation, Coma Berenices or Berenice’s Hair. As shown on the chart at the top of this post, or in the photo above from Zhean Peter Nacionales, you can draw a line from the star Regulus through the top star of the triangle (Zosma), and go about twice this distance to locate the cluster.

The Coma star cluster is also called Melotte 111. It’s visible to the unaided eye in a dark country sky. You might need binoculars to see this loose tangle of stars if your skies are beset by light pollution. It is a beautiful sight in a dark sky. Find a dark sky location near you here.

This is an open star cluster. That means its stars were probably born together from a single cloud of gas and dust in space, and they are still loosely bound by gravity. There are about 100 stars in the Coma star cluster, which lies some 288 light-years distant. In other words, this star cluster lies within our Milky Way galaxy.

Star field with scattered bright stars relatively close together.

Coma star cluster in the direction of our constellation Coma Berenices. It is an open star cluster, whose member stars are thought to be loosely bound by gravity. Image via NASA/Expedition 6.

Large galaxy with smaller fuzzy galaxies behind it.

A majestic face-on spiral galaxy located deep within the Coma Cluster of galaxies. Image via NASA.

But wait. There’s more in this direction of space: a vast collection of galaxies external to our Milky Way and the Virgo supercluster of galaxies.

The Coma galaxy cluster, also in the direction of the constellation Coma Berenices, is made up not of individual stars, but of whole galaxies of stars.

It is invisible to the unaided eye (or even in a small telescope), but astronomers with large telescopes study this region of space to learn more about the cosmos.

Coma Cluster: Galaxies in Coma Berenices

Moon and morning planets in April 2020.

Are you a morning person? Then wake up before dawn on April 14, 2020, to behold the moon and morning planets. Read more.

Bottom line: On springtime evenings, star-hop from the constellation Leo to the Coma star cluster in the constellation Coma Berenices. Plus – although you cannot see it with your eye or with binoculars – a huge cluster of external galaxies lies in the direction of Coma Berenices.

Moon, 3 planets before daybreak April 14-16

Moon and morning planets on April 14, 15 and 16, 2020.

Before daybreak these next several mornings – April 14, 15 and 16, 2020 – watch for the moon to flit by three morning planets: Jupiter, Mars and Saturn. Around the world on April 14, the moon’s illuminated side points right at this compact line-up of planets.

Jupiter, at top, is easily the most brilliant of the bunch, beaming some 14 times brighter than either Saturn or Mars. Even so, Mars and Saturn are respectably bright, shining as brightly as 1st-magnitude stars. Mars lodges at bottom of this parade of planets, whereas Saturn is found in between Mars and Jupiter.

Of course, these worlds shine by reflecting the light of the sun. At present, Mars and Saturn are pretty much equally bright. But it’s fairly easy to distinguish these two worlds by color. Mars glowers red whereas Saturn exhibits a golden hue. If you have difficulty seeing color with the eye alone, try your luck with binoculars.

The relative sizes of the solar system planets via NASA. Distances are NOT to scale. Mercury and Venus are called inferior planets because they orbit the sun inside of Earth’s orbit.

Mercury, the innermost planet, is nominally a morning planet all though April 2020. However, it’ll be buried too deeply in the glow of morning twilight to be visible from northerly latitudes. At the equator, Mercury rises about one hour before the sun, and at 35 degrees south latitude, Mercury rises about 1 1/2 hours before sunrise.

Moon and morning planets from the Southern hemisphere.

The view of the moon and morning planets from the Southern Hemisphere (Cape Town, South Africa) before sunrise April 16, 2020.

That places 4 of the 5 bright planets in the April 2020 morning sky. The brightest planet of them all – Venus – is found in the west after sunset, and will remain a fixture of the evening sky for the next 1 1/2 months. Watch for Venus to shine at its brilliant best as the evening “star” in late April 2020.

Mercury and Venus are called inferior planets, because they orbit the sun inside of Earth’s orbit. Inferior planets exhibit the whole range of phases, much like our own moon does. You need a telescope to watch these changing phases, however. Right now presents a great time for watching Venus through a telescope because Venus is now displaying a waning crescent phase, which is much easier to discern than a gibbous phase.

As Venus comes closer to Earth in the evening sky, its phase shrinks but its disk size enlarges. The converse is also true. Whenever Venus gets farther away from Earth in the morning sky, its phase increase but its disk size diminishes. Image credit: Statis Kalyvis

On the other hand, a superior planet is a planet that orbits the sun outside of Earth’s orbit. Get up before dawn these next several days – April 14, 15 and 16, 2020 – to see the moon and the 3 bright superior planets in the morning sky: Mars, Jupiter and Saturn.

Look for the legendary green flash April 16, 2020

The green flash image at the top of this post was taken by Jim Grant, an EarthSky friend on Facebook. He captured it off the coast of Ocean Beach, California, and identified it a mock mirage green flash.

It’s not hard to see a green flash with the eye alone, when sky conditions are right, and when you’re looking toward a very clear and very distant horizon. That’s why those who live near an ocean tend to report green flashes most often. A sea horizon is the best place to see them.

The video below, posted to EarthSky by Vladek in 2016, is an excellent example of the experience of seeing a green flash:

Most people see green flashes just at sunset, at the last moment before the sun disappears below the horizon. Be careful and don’t look too soon. If you do look too soon, the light of the sunset will dazzle (or damage) your eyes, and you’ll miss your green flash chance that day. But if you wait – looking away until just the thinnest rim of the sun appears above the horizon – that day’s green flash could be yours.

Of course, the green flash can be seen before sunrise, too, although it’s harder at that time of day to know precisely when to look.

Pyramid-like deep orange setting sun with green smudge at top.

Mock mirage and green flash seen from San Francisco in 2006. Image via Brocken Inaglory/Wikimedia Commons.

There are many different types of green flash. Some describe a streak or ray of the color green … like a green flame shooting up from the sunrise or sunset horizon.

The most common green flash, though – the one most people describe – is a flash of the color green seen when the sun is nearly entirely below the horizon.

Again … you need a distant horizon to see any of these phenomena, and you need a distinct edge to the horizon. That’s why these green flashes, streaks, and rays are most often seen over the ocean. But you can see them over land, too, if your horizon is far enough away. Pollution or haze on the horizon will hide this instantaneous flash of the color green.

Orange sky, blue sea, tugboat silhouette with green smudge on horizon.

Jim Grant photographed this green flash on April 27, 2012, off the coast of San Diego.

If you’re interested in green flashes, Andrew Young’s green flash page is great. He also has a page of links to pictures of green flashes taken by people from around the globe.

And, of course, Les Cowley at the great website Atmospheric Optics devotes many pages to the green flash phenomenon. Notice the menu bar at the left side of the page; it’ll let you explore many different types of green flashes.

Yellow pyramid with tall tower silhouetted in center and bright green top.

Green flash atop sun pyramid via astrophotographer Colin Legg in Australia.

Bottom line: The green flash is legendary, and some people have told us they thought it was a myth, like a unicorn or a pot of gold at the end of a rainbow. But green flashes are very real. You need a distant and exceedingly clear horizon to see them at the last moment before the sun disappears below the horizon at sunset.

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Old moon and morning planets on April 17, 2020.

Are you an early riser? Then catch the old moon beneath the line-up of three bright morning planets: Jupiter, Saturn and Mars.

Leo loses his tail. We gain a constellation April 17

Tonight’s chart shows the sky in April high to the south around mid-evening. To the upper left of the constellation Leo the Lion are dozens of very faint stars. They make up the constellation Coma Berenices, otherwise known as Berenice’s Hair. You need a dark sky to appreciate the constellation Coma Berenices. If you have one … it’s very beautiful.

The Greek-Egyptian astronomer Ptolemy and others considered these stars the tuft at the end of Leo the Lion’s tail. Coma Berenices remained part of Leo until a few hundred years ago, when it was first listed as a separate constellation.

The story goes that an ancient Egyptian queen, Berenice, feared for her husband’s life as he went into battle. She prayed to Aphrodite, promising to cut off her long, luxurious curls if the king returned safely. He did, and Berenice kept her promise and cut off her hair, placing it as a sacrifice on Aphrodite’s altar.

But the next day the hair was gone!

Star chart with stars in black on white background.

The constellation Coma Berenices. Click here for a larger sky chart.

The king was enraged that the temple priests had not protected the precious locks. A quick-thinking astronomer saved the day, or rather night, by pointing to the cascading stars at the end of Leo’s tail. He told the king that these were the queen’s tresses placed in the sky by Aphrodite for all to see.

The king and queen were appeased, and no priests were beheaded.

Large spiral galaxy with smaller fuzzy oblong galaxies behind it.

There’s a vast cluster of galaxies located in the direction of the constellation Coma Berenices. Here is a majestic face-on spiral galaxy located deep within the Coma Cluster. Read more about the Coma galaxy cluster. Image via NASA.

Bottom line: The constellation Leo once had a tail, a clump of faint stars. Now these same stars are known as Coma Berenices, the hair of a queen.

Spica, guide star to Omega Centauri April 18

Chart at top via skyandtelescope.com

In April and throughout the month of May, let the sparkling blue-white star Spica help you find the famous Omega Centauri globular star cluster. In mid-April, Spica and Omega Centauri climb highest up for the night at or around midnight ( 1 a.m. daylight saving time).

What is Omega Centauri? It’s the largest and finest globular star cluster visible to the eye alone. Globular clusters are large, symmetrically shaped groupings of stars, fairly evenly distributed around the core of our Milky Way galaxy. Many northern stargazers have this particular cluster on their bucket lists.

Seeing Omega Centauri is very special in part because you can see it with your eye alone, assuming you have a dark enough sky. Very few of the Milky Way galaxy’s 250 or so globular star clusters are readily visible without optics.

Like all globular clusters, Omega Centauri is best seen through a telescope. Then you see it as a globe-shaped stellar city, teeming with an estimated 10 million stars!

Fuzzy dot in sky with enlargement showing larger fuzzy dot with some star detail.

The Omega Centauri star cluster from Greg Hogan in Kathleen, Georgia. Thanks, Greg!

How can I find Spica, and then the cluster? From Northern Hemisphere locations, you can use the Big Dipper to find Spica. Just “follow the arc” in the Big Dipper’s handle to the bright orange star Arcturus, then “drive a spike” (keep extending that arc) to Spica.

In late April and early May, Spica transits – climbs to its highest point in the sky – around 11 p.m. (12 midnight daylight saving time) for all locations around the globe. With each passing week, Spica will transit half an hour earlier. By mid-May, Spica will be transiting (appearing highest in the sky) around 10 p.m. (11 p.m. daylight saving time).

When Spica is highest in the south for Northern Hemisphere viewers, Omega Centauri is, too. When Spica is highest, look for Omega Centauri about 35 degrees directly below it. A fist at an arm’s length approximates 10 degrees.

You can see Omega Centauri with the unaided eye if your sky is dark enough and if you’re far enough south on the Earth. People living south of 35 degrees north latitude have a realistic chance of spotting the cluster over the southern horizon, though Omega Centauri has been seen as far north as Point Pelee National Park in Canada (42 degrees north latitude). Omega Centauri looks like a fairly faint (and possibly fuzzy) star.

And, of course, it’s awesome from the Southern Hemisphere.

Arc to Arcturus and spike to Spica star chart.

Extend the arc of the Big Dipper handle to arc to Arcuturus and to spike Spica!

Large round conglomeration of uncountable stars dense in the middle, less so at edges.

The globular cluster Omega Centauri — with as many as 10 million stars — is seen in all its splendor in this image captured from the European Southern Observatory’s La Silla Observatory in Chile.

What if I’m in the Southern Hemisphere? As seen from the Southern Hemisphere, Spica and Omega Centauri pass more nearly overhead. They still transit at approximately the same time (midnight in mid-April, 10 p.m. in mid-May). They’re still located about 35 degrees apart.

From the Southern Hemisphere, you’ve got a beautiful way to find this cluster. And, indeed, your view of the cluster will be better than ours in the north, because Omega Centauri will be higher in your sky.

To get in its general vicinity on the sky’s dome, look for the famous Southern Cross, which, officially, is the constellation Crux. Along the eastern edge of Crux is the dark Coalsack Nebula. Near the Coalsack – visible in binoculars – is the Jewel Box, an open star cluster with about 100 members, whose stars are colored red, white and blue.

If you can locate these objects, you’ll also find Omega Centauri. Consult the chart below for its location.

Southern Hemisphere view with Southern Cross and Omega Centauri cluster at top.

Chart via Space-Talk.

Telescopic view of fuzzy dot, stars visible around edges, in star field.

View larger. | Omega Centauri in March, 2016, by Rob Pettengill in Terlingua, Texas.

Bottom line: From the Northern Hemisphere, you can use the star Spica in the constellation Virgo to locate Omega Centauri on springtime nights! From the Southern Hemisphere, star hop from the Southern Cross, to the dark Coalsack Nebula, to the Jewel Box star cluster, to Omega Centauri.

Lyrid meteor shower best before dawn April 19

From EarthSky Facebook friend Guy Livesay. He wrote, ‘ Didn’t see many Lyrids on the 21st or 22nd in Eastern NC. This is from the 21st. There’s actually 2 in this shot very close together.’

Above: Photo of a Lyrid meteor via EarthSky Facebook friend Guy Livesay

It’s Lyrid meteor time! Best of all, the skinny and almost-new lunar crescent won’t obtrude on this year’s production. In a dark sky, you might see as many as 10 to 15 meteors per hour at its peak. Before dawn on Wednesday will probably feature the greatest number of meteors.

We expect some Lyrid meteors to fly between late evening on Sunday (April 19) until dawn Monday (April 20). And we anticipate a greater number of meteors from late night Monday (April 20) until dawn Tuesday (April 21). Before dawn Wednesday – April 22, 2018 – will probably be best, but try again from Wednesday night (April 22) until dawn Thursday (April 23) if you’re game. Generally, the greatest number of meteors fall in the few hours before dawn. That’s when the radiant point – near the star Vega in the constellation Lyra – is highest in the sky, and when you’re likely to see the most meteors.

Note for Southern Hemisphere observers: Because this shower’s radiant point is so far north on the sky’s dome, the star Vega rises only in the hours before dawn. It’ll be lower in the sky for you than for us farther north on Earth’s globe, when dawn breaks. That’s why you’ll see fewer Lyrid meteors. Still, you might see some! Try watching before morning dawn on April 20, 21 and 22.

Good news for all of us this year: The moon turns new less than one day after the expected peak, leaving the night sky dark for meteor-watching.

More good news: Before dawn, you can see the three planets, Jupiter, Saturn and Mars!

April 2020 morning planets.

Three bright morning planets – Jupiter, Saturn and Mars – light up the predawn/dawn sky in April 2020.

The Lyrids aren’t the sky’s richest meteor shower. You might see as many as 10 to 20 meteors per hour in the few hours before Sunday’s dawn. But the Lyrids aren’t an altogether predictable shower. In rare instances, they can bombard the sky with some 60 to 100 meteors per hour.

We’re not expecting a Lyrid meteor outburst this year, but even catching a few meteors before dawn counts as a thrill.

Plus this shower sometimes produces fireballs, or exceptionally bright meteors.

Lyrid meteors radiate from near the bright star Vega in the constellation Lyra the Harp. Read more about the Lyrid’s radiant point.

Why watch for meteors before dawn? Although there are exceptions, most meteor showers are best in the hours after midnight. The key is the shower’s radiant point, in this case in the approximate direction to the bright star Vega. This star rises over the northeast horizon by around mid-evening (9 to 10 p.m. local time) at mid-northern latitudes. South of the equator, this star rises later, in the hours before dawn. The higher that Vega appears in your sky, the more Lyrid meteors you’re likely to see. Since this brilliant beauty of a star soars to its highest point at or near dawn, the best viewing of this shower is usually around then.

Click here to find out when Vega rises into your sky.

Remember, though … you don’t have identify the meteor shower radiant point to enjoy the Lyrid meteors. The meteors radiant from a single point, but they can be seen flying in all parts of the night sky.

Read more about the Lyrid’s radiant point.

Simon Lee Waldrum caught this Lyrid meteor during 2017’s shower. Gorgeous!

Like most meteors in annual showers, Lyrid meteors are the debris of a comet orbiting the sun. They burn up in the atmosphere about 60 miles (100 km) up. Vega, meanwhile, is not really connected with the meteors. It lies trillions of times farther away at 25 light-years.

If you want to watch the shower, be sure to find a place away from artificial lights. Simply recline comfortably while looking in a relaxed way in all parts of the sky.

Manoj Kesavan caught this meteor in moonlight on the morning of April 16, as the Lyrid shower was just beginning. He was in Tongariro National Park in New Zealand. He wrote:

Manoj Kesavan caught this meteor in moonlight during 2016’s Lyrid meteor shower, from Tongariro National Park in New Zealand. He wrote: “I have seen the Milky Way rising over the volcanic complex at various seasons and moon phases. Have shot timelapes and star trails on the volcanic valley which was glacially carved out during the last ice age. This particular one is lit by almost 50 percent moonlight … this scene never gets old for me!”

Bottom line: The best time to watch Lyrid meteor shower is during the dark hours before dawn, on April 22, 2020. Try watching the mornings before and after, too.

Find Hercules between 2 bright stars April 22

Sky chart of constellation Hercules

Tonight, try locating one of the coolest constellations up there. The constellation Hercules the Kneeling Giant can be seen ascending in the east-northeast on these Northern Hemisphere spring evenings. You can find Hercules between two brilliant stars: Arcturus and Vega. The chart at the top of this post shows the sky for around 8 to 9 p.m. local time (9 to 10 p.m. daylight saving time), when the constellation Hercules, and the two stars so essential for finding it, are well up in the northeastern to eastern sky.

Arcturus is in the constellation Boötes, and Vega is in the constellation Lyra. At nightfall, Vega may still be below in your horizon. If so, wait awhile … it’ll rise soon.

A line between Arcturus and Vega passes through what is known as the Keystone – an asterism, or noticeable pattern – in Hercules. The Keystone is a squarish figure in the center of Hercules. See it on the charts above and below?

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Constellation Hercules, with its prominent Keystone asterism marked.

The constellation Hercules, with its prominent Keystone asterism marked. Image via Wikimedia Commons.

The Keystone is a helpful pattern for more reasons than one. First, it’s noticeable on the sky’s dome, so it can lead your eye to Hercules.

Also, the Keystone in Hercules can help you find the most fascinating telescopic object within the boundaries of this constellation. This object is a globular star cluster known to stargazers as M13 or the Great Cluster in Hercules. M13 is barely visible to the eye alone in the darkest of skies, but binoculars show it as a nebulous starlike patch of light. And telescopes show stars both on the periphery of the cluster and toward its center.

Star chart, black stars on white background.

The chart shows M13 (the great Hercules cluster) in the Keystone. This chart of the constellation Hercules is via the IAU.

This beautiful object is one of the galaxy’s oldest inhabitants. It’s a tightly packed spherical collection of about one million stars.

Read more: M13 or the Great Cluster in Hercules

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

Round region of densely packed stars, density fading off at edges.

M13, aka the Great Cluster in Hercules. This object is a globular star cluster, one of our galaxy’s oldest inhabitants. Photo via ESA/Hubble/NASA.

Bottom line: Use the brilliant stars Arcturus and Vega to find the constellation Hercules tonight!

How do you star hop? April 23

Amateur astronomers use star hopping to go from stars and constellations they know … to ones they don’t know yet. First, look for noticeable patterns on the sky’s dome. One very easy pattern to find at this time of year is the constellation Orion the Hunter. You’ll find it descending in the west after sunset. Orion is easy to find because it contains a very noticeable pattern of three medium-bright stars in a short straight row. These stars represent Orion’s Belt.

If you can find Orion, you can use it to star hop to Sirius, the sky’s brightest star, in the constellation Canis Major. Orion and Sirius are dropping into the sun’s glare at this time of year, so be sure to look for them soon after the sun goes down.

And that’s how you come to know the constellations. You use what you’ve already learned to build outward to find new patterns.

Star field above building roof with long red arrow from pointer stars to Polaris.

View larger. | Another example of star hopping. The two outer stars in the bowl of the Big Dipper always point to Polaris, the North Star. Photo by EarthSky Facebook friend Abhijit Juvekar. Thank you, Abhijit!

Young moon, Venus after sunset April 24-26

Young moon and Venus after sunset.

Shortly after the sun sets on April 24 and 25, 2020, look for the young waxing crescent moon, beneath the dazzling planet Venus, in your western sky. Generally, it is quite difficult to spot a young moon less one day (24 hours) after new moon. But on April 24, 2020, the world as a whole finds the moon a bit older than one day old at sunset. Fortunately, for us in North America, the moon will be nearly two days old as the sun sets on April 24.

But no matter where you live worldwide, the slender lunar crescent will be easier to spot on April 25 than on April 24. That’s because, on April 25, the moon presents a wider crescent that’s higher up in the sky at sunset – and, therefore, stays out longer after dark. On the average, the moon sets about 50 minutes later with each following day.

Don’t get too discouraged if you miss the whisker-thin moon in the haze of evening twilight on April 24. Any young moon follows the sun beneath the horizon before it gets good and dark. Given clear skies, however, there’s no way you can miss the dazzling planet Venus, the second-brightest heavenly body of nighttime, after the moon.

To see the young moon, seek out an unobstructed horizon in the direction of sunset. A young moon sits low in the sky at sunset and sets rather soon after sundown. Binoculars may come in handy to help tease out the barely perceptible crescent from the glow of evening dusk.

To find out when the sun and moon set in your sky, click on this Sunrise Sunset Calendar, remembering to check the moonrise and moonset box.

After you first spot the young moon, notice that it sinks downward until it goes beneath the horizon. Because the Earth spins on its rotational axis from west to east, the moon appears to cross our sky in the opposite direction: east to west. This is called the moon’s diurnal (daily) motion, whereby the moon travels about 1/2 degree (its own angular diameter) westward every 2 minutes, or about 15 degrees westward per hour.

Relative to the backdrop stars and planets of the zodiac, the moon travels eastward – not westward. This eastward movement of the moon in front of the constellations of the zodiac is due to the moon’s orbital motion around Earth.

Want to know which constellation of the zodiac presently backdrops the moon? Click on Heavens-Above.

The moon travels through the zodiac at the rate of about 1/2 degree (the moon’s own angular diameter) eastward per hour, or 13 degrees eastward per day.

Watch the moon’s change of position from day to day for yourself, as the young waxing moon climbs upward, toward the dazzling planet Venus.

Venus at its brightest in late April – April 27

Moon and Venus highlight evening sky.

Late April 2020 presents the planet Venus at its brightest as the evening “star” for all of this year. No matter where you live worldwide, look west after sunset to marvel at this brilliant beauty lighting up the evening dusk first thing after sunset. Given clear skies, it’ll be almost impossible to miss Venus, the third-brightest celestial body in all the heavens, after the sun and moon, respectively.

At its brightest, Venus is nearly 3 times brighter than at its faintest. Even so, Venus always ranks as the second-brightest heavenly body in the night sky, easily outshining all other planets and stars. Venus’ reign in the evening sky started on August 14, 2019, and will come to an end on June 3, 2020. But these next several days, at dusk and early evening, Venus will be shining at her brightest best in the evening sky.

Chart showing Northern Hemisphere track of Venus from August 2019 to June 2020.

Chart by Guy Ottewell via his blog. The chart depicts Venus’ disk size and phase in the evening sky from superior conjunction (August 14, 2019) to inferior conjunction (June 3, 2020).

On April 28, 2020, at 1:00 Universal Time (April 27, 2020, at 8 p.m. CDT), Venus reaches what is called its greatest illuminated extent – at which juncture the illuminated portion of Venus covers the greatest square area o the sky’s dome. It is at or near greatest illuminated extent that Venus shines at its maximum magnitude.

Although you need a telescope to view Venus’ disk and changing phases, Venus’ disk is smallest when Venus first enters the evening sky at full phase (superior conjunction). See the diagram below. Superior conjunction last happened on August 14, 2019, when Venus was on the far side of the sun and farthest from Earth. Moreover, this was when Venus was in the sun’s glare and not yet visible in Earth’s evening sky.

Earth's and Venus' orbits

Earth and Venus orbit the sun counterclockwise as seen from the north side of the solar system. Venus reaches its greatest eastern elongation in the evening sky about 72 days before inferior conjunction and its greatest western elongation in the morning sky about 72 days after inferior conjunction. Greatest illuminated extent for Venus comes midway between a greatest elongation and an inferior conjunction.

Venus’ disk is largest when Venus leaves the evening sky some 292 days later at new phase (inferior conjunction). However, the dark side of Venus is facing Earth, and Venus is again lost in the sun’s glare. Inferior conjunction will next happen on June 3, 2020.

It might be hard to believe, but Venus shines at its brightest in our sky when she’s displaying a crescent phase (approximately 25 percent illuminated). It’s as a crescent that Venus’ daytime side, or illuminated side, covers the maximum area of sky. It’s at or near greatest illuminated extent that Venus appears brightest in our sky.

Here is a collection of Venus images from December 2016 to February 2017 showing how the size and phase of Venus has changed as it starts to move between the Earth and the Sun. Eventually, Venus will pass between the Earth and sun and emerge into the morning sky once again. Image via our friend Tom Wildoner at LeisurelyScientist.com.

Venus’ greatest illuminated extent in the evening sky (April 28, 2020) always happens about 36 days after Venus reaches greatest eastern (evening) elongation (March 24, 2020), and some 36 days before Venus sweeps to inferior conjunction (June 3, 2020). At its greatest elongation, in either the evening or morning sky, Venus’ disk is approximately 50 percent covered over in sunshine.

On the other hand, Venus’ greatest illuminated extent in the morning sky (July 10, 2020) comes some 36 days after inferior conjunction (June 3, 2020) yet 36 days before reaching greatest western (morning) elongation (August 13, 2020).

Let the golden triangle help you to remember these Venus’ milestones. The two base angles equal 72 degrees and the apex angle equals 36 degrees. Quite by coincidence, Venus’ greatest elongations happen some 72 days before and after inferior conjunction, and Venus’ greatest illuminated extent happens some 36 days before and after inferior conjunction.

Golden Triangle

The Golden Triangle, with the apex angle = 36 degrees and base angles = 72 degrees

Look west after sunset to behold dazzling Venus, the sky’s brightest planet shining at her brightest best in the evening sky!

April’s 2nd first quarter moon on April 30

Above photo: First quarter moon as captured by Duke Marsh in Indiana. Thank you, Duke!

Tonight – April 30, 2020 – the moon is at or near its first quarter phase, as darkness falls around the world. At first quarter moon, the moon is 90 degrees east of the sun on the sky’s dome, and its disk is half-illuminated by sunshine. About one week from now – on May 7, 2020 – the moon will turn full when it’s 180 degrees from the sun in our sky, when its disk is totally illuminated by sunshine.

Moon phase diagram with sun at right: 1) new moon, 2) waxing crescent, 3) first quarter, 4) waning gibbous, 5) full moon, 6) waning gibbous, 7) last quarter, 8) waning crescent. At first quarter phase, the sun-Earth-moon angle = 90 degrees, with the Earth at the vertex of this right angle.

This first quarter moon presents the second of two April 2020 first quarter moons, with the first one falling on April 1, 2020. It’s the only time this year that two first quarter moons take place in a single calendar month, though the event probably won’t generate much fanfare. Later on this year, two full moons will occur in October 2020, and the second of these two full moons will be celebrated by many people around the world as a Blue Moon.

Moon phases 2020.

In the year 2020, there are 13 first quarter moons and 13 full moons. Therefore, the month of April has two first quarter moons, and the month of October has two full moons. Moon phases via Astropixels.

The second first quarter moon of April 2020 comes on April 30, 2020, at 20:38 (8:38 p.m.) UTC. At the United States’ time zones, that gives the local clock time for the first quarter moon as 4:38 p.m. EDT, 3:38 p.m. CDT, 2:38 p.m. MDT and 1:38 p.m. PDT. Although the moon will be slightly past its first quarter phase as darkness falls over North America on April 30, you can still see the moon at the instant of its first quarter phase in a daytime sky.

Click on this Sunrise Sunset Calendar to find out the moon’s rising time, remembering to check the moonrise and moonset box.

This first quarter moon shines in front of the constellation Cancer the Crab, one of the faintest constellations of the zodiac. Because the first quarter moon is 90 degrees east of the sun on the sky’s dome, the first quarter moon shows you where the sun will be shining in front of the constellations of the zodiac some 3 months (or 1/4 year) from now: on or near July 30, 2020.

Click on Heavens-Above to know which constellation of the zodiac backdrops the moon.

Chart of the constellation Cancer via IAU (International Astronomical Association).

The sun will pass in front of the constellation Cancer from July 20 to August 10, 2020. Of course, the constellation Cancer will then be invisible because it’ll be rising and setting with the sun, and will be lost in the solar glare.

Read more: Sun in zodiac constellations, 2020

Tonight – April 30, 2020 – enjoy the second of two April first quarter moons, as it lights up Cancer the Crab, one of the faintest constellations of the zodiac.

Night Sky Observing Tips

Adjust to the dark: If you wish to observe faint objects, such as meteors or dim stars, give your eyes at least 15 minutes to adjust to the darkness.

Light Pollution: Even from a big city, one can see the moon, a handful of bright stars and sometimes the brightest planets. But to fully enjoy the heavens — especially a meteor shower, the constellations, or to see the amazing swath across the sky that represents our view toward the center of the Milky Way Galaxy — rural areas are best for night sky viewing. If you’re stuck in a city or suburban area, a building can be used to block ambient light (or moonlight) to help reveal fainter objects. If you’re in the suburbs, simply turning off outdoor lights can help.

Prepare for skywatching: If you plan to be out for more than a few minutes, and it’s not a warm summer evening, dress warmer than you think necessary. An hour of observing a winter meteor shower can chill you to the bone. A blanket or lounge chair will prove much more comfortable than standing or sitting in a chair and craning your neck to see overhead.

Daytime sky watching: When Venus is visible (that is, not in front of or behind the sun) it can often be spotted during the day. But you’ll need to know where to look. A sky map is helpful. When the sun has large sunspots, they can be seen without a telescope. However, it’s unsafe to look at the sun without protective eye wear. See our video on how to safely observe the sun, or our safe sun watching info-graphic.