Skywatch Line for Friday, December 25 through Sunday, December 27, 2020

This is Dudley Observatory’s Skywatch Line for Friday, December 25, through Sunday, December 27, written by Sam Salem.

On Friday, Sun rises at 7:25am and sets at 4:27pm; Moon sets at 2:58am and rises at 1:41pm. On Friday, the pole-to-pole terminator that divides the lit and dark hemispheres of the waxing gibbous Moon will fall to the left of Sinus Iridum, the Bay of Rainbows. The circular 155-mile diameter feature is a large impact crater that was flooded by the same basalts that filled the much larger Mare Imbrium to its right forming a rounded, handle-shape on the western edge of that mare. You can see it easily in binoculars and backyard telescopes.

On Saturday and Sunday nights, the waxing gibbous Moon shines in front of the constellation Taurus the Bull. Despite the lunar glare, you might see this constellation’s two major signposts, the star Aldebaran and the Pleiades star cluster, or the Seven Sisters. Aldebaran marks the tip of a V-shaped pattern of stars, a star cluster called the Hyades, representing the Bull’s face. Aldebaran isn’t part of this star cluster. It’s a chance alignment, with the Hyades cluster at more than twice Aldebaran’s distance away. Ruddy Aldebaran depicts the Bull’s red eye.

On Friday, as Jupiter and Saturn move apart, they’re sinking quite low in the southwest in twilight. Jupiter and Saturn separation widens to 0.5 degrees on Friday. They’ll fit together in telescopes’ low-power view. Don’t expect to see much of any telescopic detail on the two planets due to the poor atmospheric seeing at their low altitude. Mars, about magnitude –0.5 in constellation Pisces, shines bright yellow-orange very high in the south during early evening.

On Friday, lookout for a flying sleigh, one reindeer in the sky, Rangifer. This is one of the old star constellations. Today, astronomers recognize 88 constellations outlined by the International Astronomical Union. Before this ruling, the way constellations were drawn and named wasn’t regulated. Therefore, many constellations have come and gone. Rangifer is one of these extinct constellations. This reindeer-shaped pattern of stars was created by 18th-century French astronomer Pierre Charles Le Monnier. The constellation has also been called by the name Tarandus. Both words mean “reindeer” in Latin. You can find them in the region between Polaris and Cassiopeia, where Camelopardalis and Cepheus reside. You may need a dark location with no clouds to be able to locate these faint constellations.

Friday marks the 378th. birthday of Sir Isaac Newton. The English physicist and mathematician, widely recognized as one of the most influential scientists of all time and a key figure in the scientific revolution, laid the foundations for classical mechanics. Additionally, Newton made seminal contributions to optics, and he shares credit with Leibniz for the development of calculus. He built the first practical reflecting telescope. The statement of his three laws of motion is fundamental in the study of mechanics. Newton was the first to describe the Moon as falling in a circle around the earth under the same influence of gravity as a falling apple, embodied in his law of universal gravitation.

Skywatch Line for Wednesday, December 23rd and Thursday, December 24th, 2020

This is the Dudley Observatory Skywatch Line for Wednesday, December 23rd, and Thursday, December 24th, written by Louis Suarato.

The 67% illuminated, waxing gibbous Moon rises at 12:56 p.m. Wednesday in the constellation Pisces. Look for Mars 5 degrees above the Moon. Thursday night, Uranus will be 3 degrees above the Moon. The Moon reaches apogee, its farthest from Earth during this lunar cycle, at 11:51 a.m. Thursday, at the distance of 251,663 miles. In the west-southwest at twilight, Saturn and Jupiter are separating after their close conjunction on December 21st. The two gas giants are also moving closer to the horizon after each sunset. Venus rises at 5:39 Thursday morning. You’ll require a clear southeastern horizon to observe Venus before the glow of sunrise overwhelms it.

There are about 150 globular clusters within our Milky Way galaxy. New technology has allowed astronomers to discover globular clusters in other galaxies. Ground based telescopes equipped with electronic digital detectors, and the Hubble telescope’s optical, ultraviolet, and infrared imaging reveal magnitudes, colors, and distribution of globular clusters beyond our galaxy. These new discoveries have helped determine that some globular clusters are metal rich, while others are comprised of little metal elements. The denser, metal rich globular clusters tend to be located at the outside of the galaxies, while the lighter clusters are closer to the core. M2 is a globular cluster located in the constellation Aquarius. Discovered by Jean-Dominique Maraldi in 1746, M2 is one of the largest known globular clusters, having a diameter of 175 light-years. It is also estimated to be one of the Milky Way’s oldest globular clusters, at an age of 13 billion years old. M2 contains about 150,000 stars. Look for M2 about 30 degrees above Saturn and Jupiter above the southwestern horizon.

There will be an extremely bright pass of the International Space Station over our region beginning at 5:54 a.m. Thursday. The 3.4 magnitude ISS will appear high in the west-northwestern sky, to the right of the Gemini twins, Castor and Pollux. The ISS will cross the constellation Lynx before passing close by Polaris, the North Star. The ISS will then sail between Cepheus and Draco before disappearing into the northeastern horizon.

Skywatch Line for Monday December 21st and Tuesday December 22nd, 2020

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday December 21st, and 22nd, written by Joe Slomka.

The Sun sets at 4:25 PM; night falls at 6:07. Dawn breaks at 5:40 AM and ends with sunrise at 7:23

Monday is a busy day for astronomy. The Winter Solstice happens at 5:02 AM. The Sun appears at its lowest point in the sky. This event marks the first day of winter. From then on, the noonday Sun is a bit higher in the sky. The Sun also rises earlier until June 21- the first day of summer. You can measure the progress of the Sun for yourself. Simply note where the Sun rises or sets Monday. Every few days, note that the Sun rises or sets a bit closer to the North. This simple experiment replicates the first calendars that ancient cultures devised.

The Moon rises on Monday at 12:13 PM and sets at 11:57 PM. Tuesday, the Moon rises at 12:35 PM and sets at 12:58 AM, Wednesday. Monday’s Moon becomes 1st Quarter at 6:41 PM, 50% illuminated and 7 days old.

Last week, we talked about the famous Geminid meteor shower. However, December also stages the Ursid shower. The annual Ursid Meteor Shower peaks Tuesday at 4 AM. As the name implies, the Ursids seem to originate from the constellation Ursa Minor (the Little Dipper). Unlike the Geminids, which are spawned by an asteroid, the Ursids are debris from Comet 8P/Tuttle, which circles the Sun in 13 years. Expect to see about 10 meteors per hour, appearing near Kochab, the brightest star in the Little Dipper. Since the Moon sets around midnight, that is the optimum time for observing.

Mars rises in Pisces at 12:41 PM and continues to dim and shrink. It shines with minus zero magnitude, appears 12 moderate arc-seconds, is best seen at 7:16 PM and sets at 1:53 AM.

Venus, in Ophiuchus, rises shortly before the Sun at 5:35 AM. It blazes with minus 4th magnitude, 11 arc-seconds in size and sets during daytime. Since it rises close to the Sun, the early bird should use binoculars and search the southeastern sky before it becomes too bright.

Jupiter and Saturn are the main event for Monday. They jointly rise in Capricornus at 9:24 AM. Jupiter glows with minus 2nd magnitude and appears 33 arc-seconds large; Saturn shines with zero magnitude and is half Jupiter’s size. Both set at 6:40 PM.

Objects are in conjunction when they share the same space in the sky. Monday, Jupiter and Saturn are as close as can be. By 6 PM, they are about 6° above the southwestern horizon. They will be 0.1° apart, easily sharing the low power view in binoculars and telescopes. Jupiter and Saturn experience conjunctions every 20 years. This Great Conjunction is the closest since 1563, while the conjunction of 1226 was even closer. Sky watchers are suggested to begin observing about 90-45 minutes before the planets set. The event should be naked-eye visible, but have low power binoculars or telescopes available if the observer has difficulty finding them. In addition, all 4 Galilean moons will be visible in binoculars.

Some astronomers think that the triple conjunction of Jupiter and Saturn in 7 BC was the Star of Bethlehem. Others look to the triple conjunction of Venus and Jupiter between the years 3 and 2 BC. During that conjunction, they actually eclipsed each other on June 17, 2 BC.

Skywatch Line for Friday, December 18, through Sunday, December 20, 2020

This is Dudley Observatory’s Skywatch Line for Friday, December 18, through Sunday, December 20, written by Sam Salem.

On Friday, Sun rises at 7:21am and sets at 4:23pm; Moon rises at 10:52am and sets at 8:45pm.

The Moon low in the south at sunset, but there are a few hours of darkness to observe before it sinks below the horizon around 8:45pm on Friday. Zoom in on the Moon for a look at an interesting crater doublet, Messier and Messier A. Look with a telescope toward the Moon’s eastern limb, along its equator. There you’ll find the large crater Langrenus, with its distinctive central peaks. To the northwest of this crater is a small pair of impacts. The westernmost pockmark has a distinctive comet-like trail of debris spreading farther west. These are Messier and Messier A, named for the famous 18th-century comet hunter Charles Messier. The pair’s strange appearance is attributed to a single impact that struck the Moon at a low angle and essentially skipped once along the surface. Bump your magnification up to see the Messier doublet distinctly out of round when compared with its fellow craters. Come back over the next few nights for better views of its one-way rays, as the changing Sun angle brings them into even better contrast. Use a lunar map to help you locate these features.

Venus, at magnitude –3.9 near the head of constellation Scorpius, shines low in the southeast during early dawn. As dawn advances, watch Venus climb higher as it fades into the growing daylight.

Jupiter and Saturn shine close together in the southwest during and after twilight. Their separation shrinks to 0.3 degrees this weekend. The two planets fit together in many telescopes’ low-power field of view. Mars, at magnitude –0.7 in constellation Pisces, shines bright yellow-orange, very high in the southern sky during evening. Mars is still 13 or 12 arcseconds wide in a telescope, big enough to show surface detail during steady seeing. It’s gibbous, 90% sunlit from Earth’s point of view. Its recent dust storms seem to be over.

To view the Southern Cross, also known as the constellation Crux, you have to be close to the tropics, Hawaii, or the southernmost parts of Texas or Florida. The Northern Cross isn’t as famous as its counterpart visible from the Southern Hemisphere or the northern tropics. But the Northern Cross also looks like a cross, and it’s easy to spot. The star Deneb marks the top of the Northern Cross and the star Albireo marks the bottom. You can find the Northern Cross shining fairly high in the west at nightfall any night in late December. It sinks downward during the evening hours and stands over the west-northwest horizon around mid-evening. The Northern Cross is an asterism. It’s not a constellation but simply a noticeable pattern of stars. It’s part of the constellation Cygnus the Swan. Point your binoculars toward the Northern Cross and its larger constellation Cygnus the Swan. In this direction, you’ll find a part of our Milky Way galaxy that is called the Cygnus Star Cloud. It’s part of the spiral arm of our galaxy that also contains our Sun. You should be able to pick out stars from it if the night is clear.

Skywatch Line for Wednesday, December 16th, and Thursday, December 17th, 2020

This is the Dudley Observatory Skywatch Line for Wednesday, December 16th, and Thursday, December 17th, written by Louis Suarato.

The 6% illuminated, waxing crescent Moon sets at 6:31 p.m., Wednesday. The Moon will be low in the southwest, 2 degrees below Saturn and Jupiter. Thursday, the Moon and planets will be separated by about 10 degrees, with the Moon to the left of the planets. While the Moon, Saturn, and Jupiter are setting, Mars will be high above the southeastern horizon in the constellation Pisces. The planet Uranus can be seen with binoculars about 20 degrees to Mars’ 7 o’clock, or lower left. Venus rises at 5:23 a.m. below Libra, and above Sagittarius.

As Saturn and Jupiter are setting, Aquila, the Eagle is diving toward the horizon. Its brightest star, Altair, is the first of the stars of the Summer Triangle to go. While Altair is setting, some of the stars comprising the Winter hexagon are rising in the east. The first to rise is Capella in Auriga, followed by Aldebaran in Taurus. Pollux, in Gemini, Rigel in Orion, Procyon in Canes minor, and Sirius, in Canes Major will soon follow.

As we approach the Winter Solstice, keep a eyepiece out for a few of these winter deep sky objects. While Orion dominates the winter sky, look below the Hunter’s belt, on his sword, for M42, The Orion Nebula. Although this object can be seen with the naked eye, or binoculars, a telescopic view reveals the Trapezium Cluster at the heart of the star making machinery of the Orion Nebula. Discovered by Galileo on February 4, 1617, the Trapezium consists of five bright stars, some of which are binaries. Another open star cluster to view is M45, The Pleiades, or Seven Sisters. This star cluster is so large, it is best viewed through binoculars. Found in the constellation Taurus, The Pleiades is comprised of seven bright stars surrounded by bluish dust clouds. By far, the best galaxy to observe is M31, Andromeda. Our galactic neighbor is 2.5 billion light-years away, but with an angular size about 6 times the diameter of the Full Moon, Andromeda offers a beautiful view of its spiral arms through larger telescopes. The deepest V of Cassiopeia points to the Andromeda Galaxy high over the northwestern horizon after Astronomical twilight.

Skywatch Line for Monday December 14th and Tuesday December 15th, 2020

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday December 14th and 15th, written by Joe Slomka.

The Sun sets at 4:22 PM; night falls at 6:04. Dawn breaks at 5:37 AM and ends with sunrise at 7:19.

The Moon, in Sagittarius, turns “New” on Monday morning; the Moon sets 4:25 PM. Tuesday, the Moon rises at 8:25 AM and sets at 5:22 PM, appearing as a very thin 2% illuminated crescent. The Sun undergoes a Total Solar Eclipse on Tuesday, but very few people will see it. The eclipse begins deep in the southern Pacific and treks eastward. It encounters the coast of Chile, spends 4 minutes in that country and crosses over into Argentina where it enters the South Atlantic and ends short of the African coast.

Sagittarius continues to contain Pluto, Jupiter and Saturn. Pluto rises first at 9:33 AM, glimmers with 14th magnitude, appears tiny and sets at 6:30 PM. Jupiter is next, rising at 9:47 AM, shines with minus 1st magnitude, appears a large 34 arc-seconds and sets at 7 PM. Saturn rises two minutes later, glistens with zero magnitude and sets at 7:04 PM. Jupiter and Saturn continue to close in on each other; tonight, they are 45 arc-minutes removed from each other.

Aquarius accommodates Neptune and Dwarf Planet 1Ceres. Neptune rises at Noon, glimmering with 8th magnitude, appearing a small 2 arc-seconds and setting at 11:14 PM. 1Ceres rises at 12:18 PM, is dimmer with 9th magnitude, appears 97% illuminated and sets at 10:01 PM. Ceres appears about 27° high in the southern sky, about 14° below Neptune and near the star Delta Aquarii.

Red Planet Mars continues to dim and shrink in Pisces. It rises at 1:03 PM, sparkles with minus zero magnitude, appears a moderate 12 arc-seconds in size, is best observed at 7:34 PM and sets at 2:07 AM. Uranus, in Aries, rises at 1:48 PM, shimmers with 5th magnitude, a small 3 arc-seconds, is best observed at 8:37 PM and sets at 3:31 AM.

With Mercury too close to the Sun, Venus, in Libra, is the last planet to appear. It rises at 5:18 AM, flashes with minus 3rd magnitude, is a moderate 11 arc-seconds and sets during daytime. Venus appears 91% lit and about 6° above the eastern horizon. Venus is easily seen with binoculars. It is easiest to spot in the time between Venus rise and Sunrise. It is also possible to see it during daytime, if you have a go-to telescope that can automatically turn to it. I have seen it on rare occasions when Venus was near a daytime Moon. Observers are cautioned to take care not to look at the Sun without special solar filters.

By 10 PM, Gemini is high in the southeastern sky, along with Orion and Canis Major. Sky watchers should notice enhanced meteor activity. This is the annual Geminid meteor shower. The shower occurs Monday night/Tuesday pre-dawn. Meteors seem to stream from the twin stars Castor and Pollux. Under ideal conditions and a dark sky, one can see 120 meteors per hour, but astronomers predict about 30 per hour. The New Moon poses no problems for meteor watchers. Light pollution reduces these numbers.

Meteor specialists predict this will be the best shower until 2023. Geminids are famous for fireballs – very bright meteors. If one goes out early, it is suggested to look to the northeast at about 8 PM. You may witness meteors skipping across Earth’s atmosphere; these are called Earth-grazers. If the forecast is for cloudy weather, try Sunday night.

Most meteor showers are the result of comet litter. But, the Geminids are the result of a three-mile long asteroid, Phaeton – the only known asteroid generated meteor shower. Astronomers discovered that Phaeton suffers from the Sun. Its close proximity to solar heat bakes Phaeton’s rocks, which crumble and shed, just like a comet’s ices.

Skywatch Line for Friday December 11, through Sunday December 13, 2020

This is Dudley Observatory’s Skywatch Line for Friday, December 11, through Sunday, December 13, written by Sam Salem.

On Friday, Sun rises at 7:16am and sets at 4:21pm; Moon rises at 3:21am and sets at 2:23pm. The sliver of old crescent Moon will be positioned several finger widths to the upper right of Venus, in the southeastern pre-dawn sky on Saturday. For several hours following sunrise, look for Venus’ bright point of light shining a short distance to the left of the Moon in daylight. Use binoculars to help you locate Venus in daylight. Venus, at magnitude –3.9 in constellation Libra, shines low in the southeast during dawn. It’s a little lower every week. Very high above Venus shines Arcturus. Look for fainter Spica less far to Venus’s upper right.

With the Moon out of the sky all night long, this year’s Geminid meteor shower will not be obstructed by moonlight. The Geminids meteor shower runs from December 4 to December 17. This year, the shower will peak before dawn on Monday. Geminids meteors are often bright and intensely colored. Geminids meteors are produced by particles dropped by asteroid 3200 Phaethon. The best time to watch for Geminids will be from full darkness on Sunday until dawn on Monday morning. At about 2 am, the sky overhead will be pointed toward the densest part of the debris field. Up to 120 meteors per hour are possible under dark sky conditions. Geminids will appear to radiate from a position in the sky above the bright stars Castor and Pollux, but the meteors can appear anywhere in the sky.

Mars, about magnitude –0.9 in constellation Pisces, shines very high on the southern side of the sky during evening. Mars is still 14 or 13 arcseconds wide in a telescope, big enough to show surface detail during steady seeing.

Uranus, at magnitude 5.7 in constellation Aries, is high in the southeast after nightfall, about 18 degrees lower left of Mars. Uranus appears as a tiny fuzzy ball at high power in a small telescope during good seeing. Try to locate the 9th-magnitude asteroid 8 Flora about 10 degrees lower right of Uranus. Neptune, at magnitude 7.9 in constellation Aquarius, is equally high in early evening, over in the south. Neptune is 2.3 arcseconds wide, harder to resolve than Uranus except in very good seeing.

Jupiter and Saturn tilt ever farther down in the southwest during and after twilight. Watch their separation shrink to about 1 degree this weekend.

Constellation Hercules rises in the east, about three hours before sunrise. An hour later, the great globular cluster in Hercules, M13, will sit about 15 degrees, and climbing, above the horizon. Find M13 about one-third of the way between Eta (η) and Zeta (ζ) Herculis. Shining at magnitude 5.3, this star cluster spans 16.6′ and is easily visible in binoculars. A telescope will bring out even more of its over 100,000 members. Embedded within the cluster’s core are three dark lanes, often called the propeller. Spanning 3′, this feature sits just southeast of the central region of the core. It’s best viewed under higher magnification in larger scopes. Using averted vision, or looking slightly away from the region you want to focus on, makes the propeller appear more easily. The Hercules Cluster is arguably the best Northern Hemisphere globular and will rise earlier each morning as the month goes on, affording better views with time.

Skywatch Line for Wednesday, December 9th, and Thursday, December 10th, 2020

This is the Dudley Observatory Skywatch Line for Wednesday, December 9th, and Thursday, December 10th, written by Louis Suarato.

The 30% illuminated, waning crescent Moon sets at 1:32 p.m., Wednesday. The Moon will rise 24% illuminated in Virgo at 2:16 a.m., Thursday, 7 degrees away from Spica. Mars sets 4 minutes after the moonrise. Saturn and Jupiter are 1 degree apart and about 20 degrees over the southwestern horizon at twilight. Jupiter is currently 5.103 astronomical units, or 474.3 million miles, from the Sun. Saturn is currently 9.99 astronomical units, or 928.6 million miles, from the Sun.

A small telescope will show both planets and their moons in the same field of view. Of all the moons in the solar system, Saturn’s largest, Titan, is most like the inner planets, in that, it has an atmosphere. Titan’s weather is similar to Earth’s since it also has wind, clouds, and rain. It differs in that, instead of water, Titan’s rain, lakes and rivers are liquid methane. NASA has recently approved the Dragonfly mission, which will lift off in 2026, and reach Titan in 2034. This mission will contain a quadcopter, about the size of a rover, that will explore the Titan’s terrain and atmosphere.

If you observe Jupiter between 6 p.m. and 7 p.m., Wednesday, you will see several Galilean moon events. At 6 p.m., Io begins its transit across the face of Jupiter. For 8 minutes, Io will join Europa’s shadow, until the shadow transit ends. Io’s shadow will also be crossing the planet until 6:50 p.m..

Venus rises in Libra at 5:05 Thursday morning. Sunrise occurs at 7:15 a.m., so you’ll only have a short period of time to view our planetary neighbor before the glow of the Sum overwhelms it.

Skywatch Line for Monday December 7th and Tuesday December 8th, 2020

This is the Dudley Observatory Skywatch Line for Monday and Tuesday December 7th, and 8th, written by Joe Slomka.

The Sun sets at 4:21 PM; night falls at 6:03. Dawn breaks at 5:32 AM and ends with sunrise at 7:13. Monday, December 7th is the earliest sunset of the year. Most people think that the earliest sunset occurs on the Winter Solstice, which happens on the 21st. But, it does not due to complexities of Earth’s angle relative to the Sun and its orbit.

The Last Quarter Moon set at 12:34 PM and rises in Leo at 11:38 PM on Monday, December 7th and appears 50% lit. Tuesday’s Moon sets at 1:10 PM and does not rise, in Virgo, until Wednesday at 12:51 AM. On December 1st, the Chinese space probe, Chang’e 5, landed on the Moon, sampled the soil and is returning to Earth with about 4 pounds of Moon rocks.

The variable star Algol, in Perseus, reaches minimum at 8:38 PM on, Tuesday. It will be about 52° high in the northeast. This is visible to the naked eye and binoculars. Sky watchers are advised to witness this event for 2 hours on each side of the minimum.

The constellation Sagittarius continues to house Pluto, Jupiter and Saturn. Dwarf Planet Pluto is the first to rise at 9:59 AM, smolders with 14th magnitude, appears tiny and sets at 6:57 PM. Jupiter rises at 10:09 AM, shines with minus 2nd magnitude, appears almost 34 arc-seconds large and sets at 7:20 PM. Saturn rises at 10:14 AM, glows with zero magnitude, appears 15 arc-seconds broad and sets at 7:29 PM. Jupiter and Saturn continue to close in on each other. Monday they will be only 1 ¼° separated. December 21 there will be 0.1° between them.

Dwarf Planet 1Ceres shares Aquarius with Neptune. Ceres rises at 12:44 PM, shines with 9th magnitude, 97% lit, and sets at 10:18 PM. Neptune rises at 12:26 PM, glitters with 8th magnitude, 2 arc-seconds small and sets at 11:41 PM. Uranus, in Aries, rises at 2:16 PM, naked eye visible at 5th magnitude, sized 3 arc-seconds and sets at 3:59 AM. Finder charts can be found in astronomy magazines and websites.

Mars, in Pisces, continues to dim and shrink, rising at 1:27 PM, radiant with minus zero magnitude, middle size at 13 arc-seconds, and setting at 2:24 AM. Venus is the last easily observed planet, rising in Libra at 5 AM, blazing with minus 4th magnitude, 11 arc-seconds, appearing 91% lit and setting during daytime. Mercury is the challenge planet. It rises in Ophiuchus during Civil Dawn at 6:43 AM, glaring with minus zero magnitude and a moderate size 4 arc-seconds. Observers, using binoculars, can attempt to find it amid the rapidly brightening sky, taking care not to accidently look at the Sun.

Every history student knows that December 7th marks the anniversary of the Japanese attack on Pearl Harbor. Few are aware of the date’s astronomical significance. The Japanese high command chose that date because the eighteen-day-old Moon rose before midnight and shone at 87%, permitting attack planes to launch and fly to their targets. However, the Moon almost helped foil the surprise raid. The Condor, an American minesweeper, spotted an enemy submarine periscope silhouetted against the moonlight. The Condor called the Ward, a destroyer, who attacked a second submarine and radioed the incident to headquarters. However, that report was not heeded. Had that information been acted upon, the American fleet would have had at least an hour and a half to prepare.

Skywatch Line for Friday, December 4, through Sunday, December 6, 2020

This is Dudley Observatory’s Skywatch Line for Friday, December 4, through Sunday, December 6, written by Sam Salem.

On Friday, Sun rises at 7:10am and sets at 4:21pm; Moon sets at 10:51am and rises at 8:09pm. When the waning gibbous Moon rises in the eastern sky on Friday, it will be positioned two finger widths to the left of the large open star cluster Beehive, or M44, in constellation Cancer. The cluster extends for two full Moon diameters across the sky. The Moon and the cluster will fit together in the field of view of binoculars. During the rest of the night the Moon’s eastward orbital motion will carry it farther from the Beehive. To best see the cluster’s stars, hide the bright Moon just outside the left edge of your binoculars’ field of view.

Venus, at magnitude –3.9 in constellation Libra, continues to shine in the eastern dawn. It’s getting a little lower every week. Far to Venus’s upper left shines Arcturus. Look for fainter Spica about half as far to Venus’s upper right.

Mars, at magnitude –1.1 in constellation Pisces, shines bright yellow in the east-southeast at dusk. Mars is still 15 or 14 arcseconds wide in a telescope, big enough to show surface detail during steady seeing. Widespread yellow dust storm activity is under way.

Jupiter and Saturn continue closing toward their record-breaking conjunction, 0.1 degree apart, on December 21st. The two giants have conjunctions about every 20 years. This will be their closest one visible since March 4, 1226. Jupiter and Saturn tilt ever farther down in the southwest during and after twilight. Watch their separation shrink to about 1.9 degrees this weekend. Don’t expect a decent view in a telescope. Earth is wheeling around to the far side of orbit from Jupiter and Saturn. Also, the low altitude seeing will be quite poor.

Uranus, at magnitude 5.7 in constellation Aries, is high in the east-southeast after nightfall, about 20 degrees, lower left, of Mars. Uranus is only 3.7 arcseconds wide, but that’s enough to appear as a tiny fuzzy ball, not a point, at high power in a small telescope with sharp optics.

On Saturday, Sunday, and Monday nights, catch the Moon and star Regulus, brightest star in the constellation Leo the Lion, rising in the east from mid-to-late evening. Get up before daybreak to view the waning gibbous Moon and star Regulus in the morning sky. Look for the Moon. That nearby bright star will be Regulus. Regulus represents the Heart of Leo the Lion. It’s the only 1st-magnitude star to sit almost squarely on the ecliptic, the Sun’s apparent annual path in front of the constellations of the zodiac. Regulus is regarded as the most important of the four Royal Stars of ancient Persia. These Royal Stars mark the four quadrants of the heavens. They are Regulus, Antares, Fomalhaut, and Aldebaran. Four to five thousand years ago, the Royal Stars defined the approximate positions of equinoxes and solstices in the sky. Regulus reigned as the summer solstice star, Antares as the autumn equinox star, Fomalhaut as the winter solstice star, and Aldebaran as the spring equinox star. Although the Royal Stars as seasonal signposts change over the long course of time, they still mark four quadrants of the heavens.