Skywatch Line for Monday and Tuesday May 16th, and 17th, 2022

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday May 16th, and 17th, written by Joe Slomka.

The Sun sets at 8:12 PM; night falls at 10:13. Dawn begins at 3:30 AM and ends with the Sun rising at 5:31.

The Full Flower Moon was officially Full after its Total Eclipse last night. Monday, the Moon rises at 9:16 PM, 33 arc-minutes in size, 99% illuminated and sets at 6:24 AM Tuesday. Note that Monday’s Moon rises with the bright star Antares, only 2° below; a great binocular view. Tuesday’s Moon resides in Scorpius, the same size but slightly thinner, rises at 10:35 PM and sets at 7:17 AM, Wednesday.

Mercury is the only evening planet, but not for long. We mentioned, last week, that Mercury was fading. Monday, it sets at the Civil Twilight (8:45 PM). The planet is preparing for Inferior Conjunction May 21st, after which it becomes a Dawn planet.

The Planetary Parade continues, but with Uranus missing; it sets before sunset. The first to rise is brilliant southern Saturn; it rises in Capricornus at 2:03 AM, shines with zero magnitude, a moderate 16 arc-seconds and is 26° high by Civil Dawn (4:58 AM). Pisces houses Neptune, Jupiter and Venus. Neptune, 30° to Saturn’s East, is next, rising a 3:13 AM, glowing with 8th magnitude, 2 arc-seconds and 19° high. Mars, 15 arc-minutes from Neptune, rises at the same time as Neptune, also 8th magnitude, 6 arc-seconds in size and also 19° high. Mars is becoming more prominent; Tuesday, Mars and Neptune are in conjunction, only 0.6° apart. Jupiter, the fourth to rise at 3:47 AM, shines with minus 2nd magnitude, a large 36 arc-seconds and also 19° high. Finally, Venus brings up the rear, rising at 4:03 AM, blazing with minus 4th magnitude, a moderate 15 arc-seconds, 73% lit and 10° high. All set during daytime.

Most people know that Mercury is the planet closest to the Sun. Over a 150 years ago, that was not certain. Urbain Leverrier, a French astronomer, had just discovered the planet Neptune by analyzing oddities in the orbit of Uranus and using Newton’s laws. Astronomers, for some time, knew of similar problems with Mercury’s orbit. Some of these issues were solved, again using Newton’s laws, but others remained unexplained. Leverrier took up the challenge and predicted that a planet could exist between the Sun and Mercury, if it had a specified orbit. In 1859, a French amateur astronomer, Edmond Lescarbault, claimed to have spotted it. Leverrier interviewed Lescarbault, proclaimed his sighting real and appropriately named the new planet Vulcan, after the Roman god of fire. However, another French astronomer named Liais was observing in Brazil at the same time as Lescarbault, and did not see it. Other reports had similar mixed results. Two New York astronomers, Lewis Swift and Christian Peters (who once headed Dudley Observatory) observed during an eclipse in 1878. They failed to find Vulcan, only sunspots. In 1915, Albert Einstein solved the mystery and discredited Vulcan. His Theory of Relativity predicted that Mercury’s orbital precession was due to Relativity effects. Several space probes now orbit the Sun and provide constant imagery; no planet has been seen.

Skywatch Line for Friday, May 13, through Sunday, May 15, 2022

This is Dudley Observatory’s Skywatch Line for Friday, May 13, through Sunday, May 15, written by Sam Salem.

On Friday, Sun rises at 5:35am and sets at 8:09pm; Moon sets at 4:19am and rises at 5:19pm.

On Friday evening, the almost full Moon is passing about 5 degrees left of Spica. Brighter Arcturus shines is 30 degrees to their upper left.

A total eclipse of the Moon occurs on Sunday night and early hours of Monday. The Lunar Eclipse will be visible from most of North America except the far northwest, and from all of Central and South America. The Moon, in Libra, will be high in the sky for many of these areas. Europe will catch mainly the partial stage of the eclipse, toward dawn on Monday. The duration of the eclipse is 5 hours and 19 minutes. The duration of totality is 1 hour and 25 minutes.

For our area, the Penumbral Lunar Eclipse begins at 9:32 pm on Sunday, The Penumbral Lunar eclipse takes place when the Moon moves through the faint, outer part of Earth’s shadow, the penumbra. This type of eclipse is not as dramatic as other types of Lunar Eclipses and is often mistaken for a regular Full Moon. The Partial Eclipse begins at 10:28 pm. Full eclipse begins at 11:29 pm, and it reaches its Maximum in the early minutes of Monday at 12:11 am. The Full Eclipse ends at 12:54 am, the Partial Eclipse ends at 1:55 am, and the Penumbral Eclipse ends at 2:51 am.

Venus and Jupiter, magnitudes –4.0 and –2.1 respectively, are the two bright “Morning Stars” shining low in the east as dawn brightens. Jupiter is the higher one. They’re pulling farther apart by 1 degree per day. The two planets are separated by 13 degrees on Saturday morning.

Mars, at magnitude +o.8 in the constellation of Aquarius, glimmers roughly 10 degrees upper right of Jupiter. Saturn, also magnitude +0.8, is in eastern Capricornus, almost 25 degrees to the upper right of Mars.

Find Pollux and Castor, the twin stars of Gemini, in the west-northwest sinking lower each night from mid-May through mid-June. Pollux and Castor rise in the east-northeast in the early evenings around New Year’s Day. At that time of year, they point straight up from the horizon. The two stars shine nearly overhead in the cold nights of February and March. Now, in the warmer evenings of late spring, Gemini stands on the west-northwestern horizon, with Pollux and Castor forming a horizontal line in the twilight.

Skywatch Line for Wednesday and Thursday, May 11 and 12, 2022

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, May 11 and 12, written by Alan French.

The Sun rises at 5:36 A.M. and sets at 8:07 P.M. on Wednesday. On Thursday it rises at 5:36 and sets at 8:08, giving us 16 minutes more daylight than a week ago.

The Moon was at first quarter Sunday and is now moving toward full, so a waxing gibbous Moon dominates the night sky. As darkness falls, you’ll find the Moon high toward the south on Wednesday night, appearing 79% full. It will be due south at 9:34 P.M. On Thursday night, as twilight ends, it will be toward the southeast and lower in the sky, and 86% in sunlight. It will be toward the south at 10:19 P.M. The Moon sets at 3:58 A.M. on Thursday and 4:20 A.M. Friday. The Moon will reach Full early Monday morning. On the night of the full Moon, the evening of May 15 and morning of May 16, we’ll have a total lunar eclipse to enjoy.

Early morning risers can enjoy a nice pass of the ISS (International Space Station) over our area on Thursday morning. The ISS will first appear at 4:23 A.M. coming up from the northwestern horizon, below the end segment of the Big Dipper and its handle. As it moves higher its motion will be faster and more obvious. By 4:25 the space station will be approaching the dipper’s handle, passing just behind the back of the bowl. After passing through the handle the ISS will pass through part of Draco, the Dragon, and then skim the bowl of the Little Dipper, above Polaris. It will then pass through more of Draco and north of Deneb, the brightest star in Cygnus the Swan. Its path will then take it down toward the east southeastern horizon. It will pass just south of Mars and disappear below the horizon after 4:31.

The morning continues to host four naked eye planets, now stretching from east to southeast. They are best seen about an hour before sunrise, perfect timing to look right after the ISS completes is journey across Thursday’s morning sky.

At 4:31 brilliant Venus will be low in the east, 4 degrees above the horizon. Bright Jupiter, will be 11 degrees to the upper right of Venus, and 9 degrees high. Mars, 12 degrees above the horizon, will be just under 10 degrees to the upper right of Jupiter. Saturn is the outliner of the group, in the southeast, 20 degrees high, and 26 degrees from Saturn.

Skywatch Line for Monday and Tuesday May 9th, and 10th, 2022

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday May 9th, and 10th, written by Joe Slomka.

The Sun sets at 8:05 PM; night falls at 10:01. Dawn begins at 3:42 AM and ends with the Sun rising at 5:38.

The Moon occupies Leo on both nights. Monday’s Moon, one day past First Quarter, rose at 12:42 AM, appears 30 arc-minutes in size, 60% illuminated and sets at 3:12 AM on Tuesday. Tuesday’s Moon rises in the Northwest at 1:48 PM, slightly smaller, 64% lit and sets at 3:35 AM, Wednesday.

Mercury is the sole evening planet and fading. In Taurus, it glows with 2nd magnitude, 10 arc-seconds, 7° high at Civil Twilight (8:37 PM), 10% crescent and sets at 9:25 PM. At the same time, the Moon lies about 4° above Leo’s brightest star, Regulus.

Tuesday’s pre-sunrise planetary parade persists. First to rise is Saturn, at 2:30 AM, shining with zero magnitude, a moderate 16 arc-seconds, and a lofty 24° at Civil Dawn (5:06 AM). Mars, rising at 3:28 AM, 24° to Saturn’s left, is equally bright, about 6 arc-seconds and 23° high. Distant Neptune lies 5° to Mars’ upper left, smolders with 8th magnitude, a tiny 2 arc-seconds, rising at 3:41 AM and 16° high. Jupiter lies 5° to Neptune’s upper left, glimmers with minus 2nd magnitude, a large 35 arc-seconds and 14° high. Venus brings up the rear, 9° to Jupiter’s left, rising at 4:11 AM, blazes with minus 4th magnitude, a moderate 15 arc-seconds, 70% illuminated and 10° high; note that Jupiter and Venus are still close, although more distant since last week. Minor planet 4Vesta is also available to the observer. Sharing Capricornus with Saturn, Vesta glows with 8th magnitude, 0.3 arc-seconds, 97% illuminated, 22° high and 3° below Saturn. Neptune and Vesta are similarly dim and tiny, posing a challenge for the sky watcher. This arrangement of planets makes binocular observing convenient by swinging eastward a few degrees.

Last week, we used Leo as a guide to Hydra; this week we employ Leo to point us to another constellation. Leo is one of those constellations that looks like its namesake. If one looks past Denebola, the Lion’s Tail, one sees a faint hazy cloud. Binoculars show it to be a galactic star cluster. This cluster is called Coma Berenices.

Unlike most constellations, Berenice was not a mythical figure. She was married to Ptolemy I Soter of Egypt. When her brother-in-law involved the Pharaoh in a war, Berenice, like all wives, worried about her husband in battle. She vowed to Aphrodite that she would donate a lock of her hair if Ptolemy arrived home safely. He did; and she fulfilled her promise. One night the royal couple inquired of the court priest-astrologer what happened to her donation. He replied by pointing to hazy cloud in the sky and said the gods accepted her sacrifice. Berenice is famous for another reason; she is Cleopatra’s grandmother. The modern Libyan city of Benghazi bears a modified version of her name. She and her husband are memorialized on the famous Rosetta Stone.

Skywatch Line for Friday, May 6, through Sunday, May 8, 2022

This is Dudley Observatory’s Skywatch Line for Friday, May 6, through Sunday, May 8, written by Sam Salem.

On Friday, Sun rises at 5:43am and sets at 8:02pm; Moon sets at 12:56am and rises at 9:33am.

The annual Eta Aquariids meteor shower will peak in intensity before dawn on Friday. Up to a few dozen meteors per hour are predicted to appear, including some fireballs. The meteor shower is produced by particles of material left behind by repeated passages of Halley’s Comet. The shower runs from April 19 to May 28. Eta Aquariids meteors will appear to be travelling away from a radiant point in Aquarius, which will rise above the southeastern horizon after 2:30am. This year, the planets Jupiter, Mars and Saturn will be positioned below the radiant. This shower is better for observers at low latitudes.

On Saturday night, watch the waxing crescent Moon close to the huge open star cluster in the constellation of Cancer known as the Beehive, Praesepe, and Messier 44. After dusk, the Moon will shine several finger widths to the upper right of the cluster. Towards midnight, the Moon will move a little closer to the Beehive. The Moon and the cluster will be close enough to share the field of binoculars. You’ll be able to see more of the stars or “bees” if you hide the Moon just outside of your field of view.

The Moon completes the first quarter of its orbit around Earth at 8:21pm on Sunday. While at first quarter, the Moon always rises around noon and sets around midnight, allowing it to be seen in the afternoon daytime sky. The evenings surrounding the first quarter phase are the best ones for viewing the lunar terrain when it is dramatically lit by low-angled sunlight.

Three zero-magnitude stars shine after dark in May. Arcturus, in the constellation of Boötes, rises high in the southeast, Vega, in the constellation of Lyra, rises much lower in the northeast, and Capella, in the constellation of Auriga, shines in the northwest. They appear so bright because each is at least 60 times as luminous as the Sun, and because they’re all relatively nearby: 37, 25, and 42 light-years from us, respectively.

Robert H. Baker may have been the first to name the Great Diamond, in his 1954 book “When the Stars Come Out”. The gigantic asterism called “Great Diamond” stands some 50 degrees tall and extends across five constellations. It’s now upright in the southeast to south after dusk. Start with Spica, its bottom. Upper left from Spica is bright Arcturus. Almost as far upper right from Arcturus is fainter Cor Caroli, 3rd magnitude. The same distance lower right from there is Denebola, the 2nd-magnitude tail tip of Leo. And then back to Spica. The bottom three of these stars, the brightest three, form a nearly perfect equilateral triangle. It’s called “Spring Triangle” to parallel to those of Summer and Winter. The first to name it such was probably the late Sky & Telescope columnist George Lovi, writing in the March 1974 issue.

Skywatch Line for Wednesday and Thursday, May 4 and 5, 2022

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, May 4 and 5, written by Alan French.

The Sun rises at 5:45 A.M. and sets at 7:59 P.M. on Wednesday. On Thursday it rises at 5:44 and sets at 8:00, giving us 17½ minutes more daylight than a week ago.

The Moon was new this past Saturday and is now moving toward first quarter, which it will reach this coming Sunday. A waxing lunar crescent now graces the early evening before midnight. On Wednesday evening look for a 15% sunlit Moon toward the west as the sky grows dark. On Thursday night the Moon will be 23% in sunlight. The Moon will set, leaving the skies dark, at 12:05 A.M. Thursday morning and 12:56 A.M. Friday morning.

With the Moon moving toward first quarter and crossing fairly high across the sky, this is good time to explore the Moon with a telescope. Any telescope will reveal a wealth of detail, especially along the terminator, the line separating the sunlit portion from the portion in darkness. This is where shadows are long and details stand out.

High in the west at 9:00 P.M., just under 50 degrees above the horizon, you’ll see a pair of bright stars, Castor and Pollux. Castor, to the right, appears white, while Pollux looks yellowish. Pollux slightly outshines Castor. They are the brightest stars in Gemini, the Twins.

Castor is a multiple star system made up of six stars. Castor A and B can be seen separately in a modest sized telescope. The system lies 51 light years from up. Pollux is closer, lying only 34 light years away.

In his 1603 star atlas, “Uranometria,” Johann Bayer placed designations on the 1,564 brightest stars. Within each constellation the stars were given a Greek letter (a, alpha; b, beta; g, gamma…) or Roman letter (a, b, c…). According to many accounts, the brightest star was given the alpha designation, the second brightest beta, and so on. The genitive of the constellation’s Latin name completed the designation, so Castor is Alpha Geminorum. Since there was no way to measure star brightness, accounts claim mistakes were made, or perhaps the brightness of some stars changed over the past four centuries. To our eye, Castor is fainter than Pollux, but Castor has the Bayer designation Alpha Geminorum and Pollux is Beta Geminorum.

According to Morton Wagman, in his book, “Lost Stars,” the explanation for the discrepancies in Bayer designations is far simpler. Bayer did not arrange stars in absolute order by magnitude, rather he arranged them by classes, simply grouping stars within a constellation of about the same brightness together.

On May 5, 2018, the Mars InSight lander was launched from the Vandenberg Launch Complex. It touched down, its descent slowed by a heat shield, parachute, and then retro-rockets, on Mars on November 26, 2018, landing on the smooth plains of Elysium Planitia, the perfect place for it to study Martian weather and the planet’s interior. It deployed a seismometer, a self-burrowing heat problem, and monitors weather conditions. It was accompanied on its trip to Mars by two briefcase-sized satellites, placed in orbit around Mars to test to test a miniaturized deep-space communications system.

Skywatch Line for Monday and Tuesday May 2nd, and 3rd, 2022

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday May 2nd, and 3rd, written by Joe Slomka.

The Sun sets at 7:57 PM; night falls at 9:49. Dawn begins at 3:55 AM and ends with the Sun rising at 5:47.

Taurus hosts the Moon on both nights. Monday’s 2-day-old Moon rises at 6:43 AM in the Northwest, appearing 30 arc-minutes in size, only 4% illuminated and sets at 10:06 PM. Tuesday’s Moon appears about the same size, 9% lit, rises at 7:15 AM and sets at 11:08 PM.

Monday evening finds the star Aldebaran, the waxing Moon, Mercury and the Pleiades star cluster arcing gracefully 29° above the Northwestern horizon. Mercury is at the midpoint of its apparition; soon it will start rapidly fading sunward at the rate of 1° per day. By next Monday it becomes difficult for the naked eye. Mercury lies about 4° below the Moon and 2° above the Pleiades.

The Dawn planetary parade continues. Saturn, in Capricornus, leads off by rising at 2:57 AM, shining with first magnitude, 19° high at Civil Dawn (5:16 AM) and 16 arc-seconds. Mars, 19° East of Saturn, rises in Aquarius at 3:44 AM, shining with first magnitude, 5 arc-seconds, 13° high and 10° East of Neptune. Venus, Neptune and Jupiter share Pisces. Neptune is next to rise at 4:08 AM, glowing with 8th magnitude, a tiny 2 arc-seconds, 10° high and 3° West of Jupiter. Gas Giant Jupiter rises at 4:15 AM, glimmers with minus 2nd magnitude, large 35 arc-seconds, 8° high and 2° East of Venus. Venus is the last to rise, at 4:20 AM, blazing with minus 4th magnitude, a moderate 16 arc-seconds, 68% lit and 7° high.

Leo’s brilliant star Regulus points to another constellation to Leo’s right – Hydra. Hydra begins with a diamond-shaped head and the rest of the body extends southward. In fact, Hydra is the longest and largest constellation. One must travel well South to enjoy Hydra to its fullest extent. Hydra is unique in that two smaller constellations lie atop it: Crater, the Cup and Corvus, the Crow. In Greek mythology, Hydra is a mythical water snake. It attacked Jason and his shipmates on the good ship Argo. In myths, Corvus was commanded by Apollo to bring a cup of water, but got sidetracked by ripening grapes. Corvus tried to excuse his tardiness by blaming the snake. Do not confuse Hydra with the similar sounding constellation Hydrus. Hydrus is relatively modern. It was one of many, invented by explorers who ventured below the equator for the first time.

Skywatch Line for Friday, April 29, through Sunday, May 1, 2022

This is Dudley Observatory’s Skywatch Line for Friday, April 29, through Sunday, May 1, written by Sam Salem.

On Friday, Sun rises at 5:52am and sets at 7:54pm; Moon rises at 5:30am and sets at 6:50pm. The second new Moon in the calendar month will occur at 4:28pm on Saturday. This new Moon will also feature a partial solar eclipse that will be visible across southeastern Pacific and the southern cone of South America. This solar eclipse will be followed by a total lunar eclipse on May 15-16.

A day after reaching its widest angle east of the Sun, on Friday, Mercury will pass less than a thumb’s width to the left of the bright Pleiades star cluster, also known as Messier 45 and the Seven Sisters, in the constellation of Taurus. The planet and the cluster will share the view in binoculars, or a backyard telescope at low magnification from Thursday to Saturday. The cluster’s stars will not be easily visible until the sky darkens around 9pm. By then, you’ll be viewing them less clearly, through a greater thickness of Earth’s atmosphere.

In the eastern sky before sunrise during late April, the rapid sunward swing of Venus will carry it past Jupiter. They’ll be close enough to share the view in binoculars from April 24 to May 6. On Saturday, look low in the southeast about 60 to 45 minutes before sunrise time. Venus and Jupiter are a spectacularly close, ½ degree apart. On Sunday morning they’ll be only a trace farther apart, with Jupiter now to Venus’s upper right. The two bright planets will appear together in the eyepiece of a backyard telescope, where six times brighter Venus will exhibit a 67 percent illuminated disk, and Jupiter will be accompanied by its four Galilean moons. The two planets will rise by about 4:30am and then remain visible until the sky brightens enough to hide them about 90 minutes later.

Mars and Saturn glimmer to the upper right of Jupiter and Venus, in that order. They’re vastly fainter, identical now at magnitude +0.9. Mars, however, is more orange than pale yellow Saturn. Each morning they’re a little farther from Venus and from each other. The Venus-Mars-Saturn line is 33 degrees long on Saturday morning. The three stay about equally spaced from each other.

The Great Cluster in the constellation Hercules, also known as Messier 13, or M13, is the finest globular cluster in the northern half of the heavens. You can find it in a star pattern called the Keystone, a lopsided square within the constellation Hercules, between the two brightest stars of northern spring and summer, Vega and Arcturus. About one-third of the way from Vega to Arcturus, locate the four modestly bright stars forming the Keystone of Hercules. On the Arcturus side of the Keystone, M13 lies between the stars Eta Herculis and Zeta Herculis. From mid-northern latitudes, the M13 cluster is in the sky for at least part of the night all year round. It is above the horizon all night long in May, June, and July. When you gaze at M13, or other globular clusters, you are looking at stars that are some 12 to 13 billion years old. That’s almost as old as the universe.

Skywatch Line for Wednesday and Thursday, April 27 and 28, 2022

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, April 27 and 28, written by Alan French.

The Sun rises at 5:55 A.M. and sets at 7:51 P.M. on Wednesday. On Thursday it rises at 5:54 and sets at 7:53, giving us 18½ minutes more daylight than a week ago. Friday will be the first day this year with more than 14 hours of sunlight.

The Moon reached last quarter Saturday morning and is headed toward new. A crescent Moon now rises before the Sun. On Wednesday morning the 12% sunlit Moon rises at 4:48 in the east. By 5:10 the slender crescent Moon will be just over three degrees above the horizon. It will be a lovely sight, with Venus and Jupiter just above. On Wednesday Jupiter and Venus will be 3.2 degrees apart, and the crescent Moon, Venus, and Jupiter trio will make a fine target for photographers. Be sure to look for Mars and Saturn stretching out to the south and upward, making a rough line with Jupiter and Venus. Mars will be 15 degrees from Venus and Saturn another 15 degrees from Mars. By Thursday morning the separation between Jupiter and Venus will have shrunk to just 2.3 degrees. They will be closest together Saturday morning, just ½ degree apart, and only slightly farther apart on Sunday morning.

On Thursday an even thinner crescent Moon, just 6% illuminated will be just rising at 5:10. By 5:30 A.M. it will be three degrees above the eastern horizon. A view low to the east and clear skies down to the horizon will allow a good view of the slender crescent. The Moon will reach new this coming Saturday morning.

Mercury is now well placed in the early evening sky. To spot it you’ll need a clear view to the west northwest. At 8:30 P.M. on Wednesday Mercury will be 12 degrees above the west northwestern horizon. By 9:00 P.M., when skies are darker, the innermost planet will still be 7 degrees above the horizon. Mercury doesn’t set until 9:46. Mercury will be slightly higher on Thursday evening,

If you are up early, there are fine passes of the ISS (International Space Station) over our area Wednesday and Thursday mornings. Wednesday’s pass will be at its highest, 64 degrees above the horizon, just after 5:12 A.M., and Thursday’s will be even higher, at a maximum 78 degrees above the horizon just after 4:24.

On Wednesday, look for the ISS moving out of the Earth’s shadow and appearing low in the west southwest at 5:10 A.M. At 5:11 it will pass north (left if you’re facing west) of bright Arcturus, the brightest star in the kite-shaped pattern of stars outlining Boötes. By 5:12 it will be gliding well above the Big Dipper in the northwestern skies and then above the Little Dipper and Polaris, the North Star. At 5:13 it will be headed down toward the W of stars marking Cassiopeia, the Queen. After passing through Cassiopeia the ISS will disappear below the northeast horizon.

Thursday morning’s fine pass will go almost overhead and the ISS will move out of the Earth’s shadow when high in the sky. Look for the ISS appearing as it moves out of our planet’s shadow when 37 degrees above the southwestern horizon seconds before 4:23 A.M. (Bright Arcturus, farther to the west, for comparison, will be 39 degrees above the horizon.) Just after 4:24 the ISS will reach its highest point in the sky, 78 degrees above the southeastern horizon, and then pass close by bright Vega. It will then go down through through Cygnus, the Swan, known to many as the Northern Cross, and close by Deneb, the constellation’s brightest star. The space station will disappear below the horizon at 4:29. Notice how its apparent motion slows as it nears the horizon, as it moves away from us toward the northeast. When high in the sky it is mostly moving across our line of sight.

Skywatch Line for Monday and Tuesday April 25th, and 26th, 2022

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday April 25th, and 26th, written by Joe Slomka.

The Sun sets at 7:49 PM; night falls at 9:37. Dawn begins at 4:09 AM and ends with the Sun rising at 5:57.

Aquarius houses the Moon on both nights. Monday’s Moon rose at 3:59 AM in the Southeast, 31 arc-seconds in size, 30% illuminated and sets at 2:17 PM. Tuesday’s Moon rises at 4:25 AM, about the same size, 21% lit and sets at 3:28 PM.

At Civil Twilight (8:20 PM), Uranus, which was the only evening planet, is now ending its run. Glowing with 6th magnitude, and a tiny 3 arc-seconds in Aries, the planet lies only 1° above the western horizon and sets at 8:26 PM. Mercury, 11° above Uranus, shining with zero magnitude, a modest 7 arc-seconds is 12° high and sets at 9:35 PM.

The darkening sky also presents two binocular opportunities. First is the Pleiades star cluster, 4° above Mercury and 17° high. The Pleiades are a great beginner object; it sets at 11:55 PM. The minor planet Ceres, above Taurus’ horns, glows with 1st magnitude.
Five degrees to Ceres’ East lies M-1; the Crab Nebula is a supernova remnant; it exploded in 1054 CE and was seen by the naked eye for over a year. In dark skies, it appears as a smudge to the eye. Binoculars present a cloud of debris; telescopes even show a birthplace for stars. “The Crab”, as it is nicknamed, sets at 11:55 PM.

The eastern Dawn sky continues its parade of bright planets, with the Moon accompanying. Saturn is the first to rise, in Capricornus, glows with 1st magnitude, a moderate 16 arc-seconds, rises at 3:23 AM and is 14° high at Civil Dawn (5:26 AM). Aquarius houses Mars and Venus. Mars rises next at 3:59 AM, 5 arc-seconds, 15° high, 90% lit and 14° East of Saturn. Venus is next, rising at 4:28 AM, blazes with minus 4th magnitude and 10° high. Jupiter, 4° from Venus, rises in Pisces, glimmers with minus 1st magnitude, a huge 34 arc-seconds, 9° high and 4° East of Jupiter. Neptune is last, rising in Aquarius at 4:35 AM, 8th magnitude, 2 arc-seconds, 10° high; Neptune is 1° from Venus and 2° from Jupiter. The Moon joins in. Monday finds it 4° below Mars and 4° below Venus on Wednesday.

Earth is not the only Solar System object with volcanoes. The Moon has several features which are thought to be extinct volcanoes. Scientists think that cloud shrouded Venus has volcanic action, though it cannot be observed. Mars has several inactive volcanoes; Olympic Mons is the largest in the Solar System. Jupiter’s Moon Io is the most volcanically active. Moons of other outer planets do not emit hot lava, rather colder substances. Europa, another Jovian moon, spews ice instead. Triton, a satellite of Neptune, also harbors an ice volcano. Saturn’s moon Enceladus erupts water ice, while Titan, another Saturnian body, emits methane ices.