Skywatch Line for Friday, October 22, through Sunday, October 24, 2021

This is Dudley Observatory’s Skywatch Line for Friday, October 22, through Sunday, October 24, written by Sam Salem.

On Friday, Sun rises at 7:17am and sets at 6:01pm; Moon sets at 9:10am and rises at 7:11pm.

There are three bright stars you might notice flashing or twinkling fiercely in the October night. They are Capella in Auriga, Arcturus in Boötes, and Sirius in Canis Major. Capella shines at magnitude 0.24, making it the 6th-brightest star in Earth’s sky, not including our Sun. And it’s low in the sky, in the northeast direction, at nightfall or early evening as seen from mid-northern locations, at this time of year. Capella is the brightest star in the constellation Auriga the Charioteer. But since antiquity it’s carried the name Goat Star. You might pick it out just by gazing northeastward from a Northern Hemisphere latitude during the evening hours in October. To be sure you’ve found Capella, look for a little triangle of stars nearby, an asterism called The Kids. Capella flashes red, blue, and green when it’s close to the horizon and seen through a thick layer of Earth’s atmosphere.

Arcturus is in the constellation Boötes the Herdsman. It’s an orange-colored star, in the northwest in the evening in October. You can always know you’ve found Arcturus if you also notice the Big Dipper, also in the northwest in early evening, nearby. The arc of the Big Dipper’s handle can be extended outward to Arcturus. Arcturus is about the same brightness as Capella, but it’s not as noticeable because on October evenings Capella is ascending in the sky and Arcturus is descending. Therefore, Capella shines most of the night, while Arcturus not long after the Sun.

Sirius in the constellation Canis Major the Greater Dog is the brightest star in the night sky. This star is famous for twinkling in different colors. Sirius is now in the south before dawn, as seen from the Northern Hemisphere.

Auriga the Charioteer is a popular constellation in autumn, because its flashing star, Capella, advertises its presence. Auriga houses three-star clusters, easy targets to hunt down with binoculars. Auriga is a north circumpolar constellation, meaning that it is close enough to the North Star that people in the Northern Hemisphere can see the constellation on any night of the year. But some times of the year are definitely better than others. If you want to see the entirety of Auriga, start looking for the constellation and flickering Capella in the autumn.

This weekend, the bright star Deneb, in constellation Cygnus, the Swan, climbs to its highest point in the sky around 7:30 p.m. This member of the famous Summer Triangle asterism is shifting ever westward in our sky each day, as Earth travels around the Sun. Its transit at nightfall in October is a hallmark of the year. It marks a shift toward winter in the Northern Hemisphere.

Skywatch Line for Wednesday, October 20, and Thursday, October 21, 2021

This is Dudley Observatory’s Skywatch Line for Wednesday, October 20, and Thursday, October 21, written by Alan French.

The Sun sets at 6:05 P.M. on Wednesday and rises at 7:17 A.M. Thursday. Sunset Thursday is at 6:6:03 and the Sun will rise at 7:18 on Friday. This Thursday has 20 minutes less daylight than last Thursday.

The Moon reaches full Wednesday morning, so a waning gibbous Moon, appearing nearly full, will rise early Wednesday and Thursday evening. Moon rise on Wednesday is at 6:23 P.M. in the east. On Thursday it rises at 6:46 in the east northeast. On Wednesday night it will be more than 99 percent illuminated and Thursday it will be 98 percent illuminated, so both nights will feature a bright, nearly full Moon.

From the Northern Hemisphere planetary observers like to point their telescopes at planets when they are due south and highest, and we view them through the thinnest possible layer of atmosphere. The two largest planets, the gas giants Saturn and Jupiter, are now due south in the early evening sky, making it convenient to catch them at their best. Saturn transits – passes due south – at 7:36 P.M., while Jupiter transits at 8:38 P.M. Unfortunately, they do not rise very high from our northern seats, with Saturn reaching an altitude of 28 degrees and Jupiter reaching 32 degrees. Still, we’ll get the best views possible from here when they transit.

Any telescope magnifying 50 to 60 times will reveal Saturn’s rings. Look for the Cassini Division, a dark gap which separates the narrower, outer A ring from the inner B ring. The visibility of the Cassini Division depends on your telescope, your eyes, and the steadiness of the atmosphere.

Any modest telescope will show the four Galilean moons of Jupiter, appearing as stars, roughly in a line, to the east and west of the planet. Around 8:38 P.M. Wednesday you’ll only see two moons, Europa to the east and Ganymede to the west and farther away. (Some telescopes will reverse the positions of the moons.) The other two moons, Io and Callisto, will be passing in front of the planet and very difficult to spot – a good challenge for larger telescopes and an experienced eye. Even then, they may elude detection, their visibility depending on the contrast between the moon and the Jovian background’s color and brightness.

At 8:41 P.M. Wednesday the shadow cast by Io will move onto the east side of the planet. The dark, black shadows are far easier to spot than the moons themselves. If you look and don’t spot it at first, give it some time to move farther west and more “onto” the planet’s disk. If you’re still watching, or look again, at 9:45 P.M., Io will move off the western limb (edge) of Jupiter, first appearing as a small bump. At 10:59 Io’s shadow will move off the planet.

On Thursday night around 8:38 P.M. all four moons will be visible. Europa and Io will be to the east, close to the planet’s limb, and Ganymede and Callisto to the west, farther away than the eastern duo.

Take some time to carefully look at Jupiter. Look for two dark bands, the North and South Equatorial belts, crossing the planet from east to west. Depending on the telescope and steadiness of the atmosphere, or seeing, you may see other details, so look carefully. The steadiness of the view often varies from minute to minute, so patience may be rewarded.

Skywatch Line for Friday, October 15, through Sunday, October 17, 2021

This is Dudley Observatory’s Skywatch Line for Friday, October 15, through Sunday, October 17, written by Sam Salem.

On Friday, Sun rises at 7:09am and sets at 6:12pm; Moon sets at 1:30am and rises at 4:29pm. The waxing Moon sweeps past bright Jupiter and fainter Saturn in the evening sky on Friday. Jupiter appears brighter than any star. Saturn appears fainter and more golden in color than Jupiter. Extend your arm and make a fist. Saturn is the brightest object within one fist-width of Jupiter to the right. Saturn is brighter than the nearby bright star Fomalhaut in constellation in the constellation Piscis Austrinus, the southern Fish.

On Sunday night, the terminator on the waxing gibbous Moon will fall west of Sinus Iridum, the Bay of Rainbows. The circular, 249-kilometre diameter feature is a large impact crater that was flooded by the same basalts that filled the much larger Mare Imbrium to its east, forming a rounded “handle” on the western edge of that mare. The “golden handle” effect is produced when sunlight strikes the prominent Montes Jura mountain range surrounding Sinus Iridum on the north and west. In a telescope, Sinus Iridum is almost craterless but hosts a set of northeast-oriented wrinkle ridges that are revealed at this Moon phase.

In the southwestern sky on the evenings around Saturday, the orbital motion of the bright planet Venus will carry it closely above the bright reddish star Antares, which marks the heart of Scorpius. At closest approach on Saturday, they’ll share the field of view in the eyepiece of a telescope at low magnification. If you have trouble seeing Antares beside 150 times brighter Venus, try hiding Venus just outside of your field of view. Venus stays close to Antares for the next two days. Watch their orientation change.

This is the time of year when, soon after nightfall, W-shaped constellation Cassiopeia stands on end halfway up the northeastern sky. Off to its left in the north, the dim Little Dipper extends directly leftward from Polaris. Cassiopeia is well placed high in the northeast together with constellations of Perseus and Auriga, the Charioteer, visible in the east.

Skywatch Line for Wednesday, October 13, and Thursday, October 14, 2021

This is Dudley Observatory’s Skywatch Line for Wednesday, October 13, and Thursday, October 14, written by Alan French.

The Sun sets at 6:16 P.M. on Wednesday and rises at 7:08 A.M. Thursday. Sunset Thursday is at 6:14 and the Sun will rise at 7:09 on Friday.

The Moon reached first quarter late Tuesday evening so a waxing gibbous Moon will grace our evening sky. The Moon will reach full on Wednesday, October 20.

At 7:45 P.M. Wednesday night the Moon will be low in the south, 22 degrees above the horizon, and 59 percent illuminated. It will lie among the stars of the constellation Capricornus and Saturn will be just under 7 degrees to the Moon’s upper left.

On Thursday night the Moon will be due south at 8:40 P.M., still in Capricornus, 24 degrees above the horizon, and 70 percent illuminated. It will lie between the gas giants, Jupiter and Saturn, with bright Jupiter 8 degrees to the Moon’s upper left and fainter Saturn 10 degrees away to the upper right.

The Moon sets at 12:19 A.M. Thursday and 1:30 A.M. Friday.

Look low toward the northeast around 9:30 P.M. A bright star, about 20 degrees above the horizon, should catch your eye. This is Capella, the Goat Star, the brightest star in Auriga, the Charioteer. Before the internet and widely available planetarium software, this writer often got calls during the fall asking about the bright star in the northeast in the early evening. When low in the sky it certainly draws people’s attention.

Like most bright stars, Capella is bright because it is a close neighbor, lying only 42 light-years from our Sun. It is the sixth brightest star in the night sky, the third brightest in the northern celestial hemisphere, and the closest to the north celestial pole, which lies near Polaris.

Many of the stars in the night sky, although appearing as single stars to the eye, are actually multiple star systems. Many can be resolved – seen as multiple stars – through a telescope, but some simply appear too close together to be detected by eye, even with a aid of a telescope. But when their light is spread out into its spectrum by prisms, their multiple nature is revealed.

In 1899 William Wallace Campbell of Lick Observatory announced that spectroscopic studies had shown Capella was a double star. The shifting spectrum of the companion revealed it was alternately moving toward and away from Earth, showing that the companion was orbiting Capella.

We now know that Capella is actually, at least, a quadruple star system.

Skywatch Line for Monday October 11th and Tuesday October 12th, 2021

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday October 11th, and 12th, written by Joe Slomka.

The Sun sets at 6:19 PM; night falls at 7:53. Dawn begins at 5:32 AM and ends with the Sun rising at 7:06.

Sagittarius houses the Moon on both nights. Monday, the Moon rises at 1:21 PM in the South-southeast, 32 arc-minutes in size, 37% illuminated and 19° high in South by 6:47 PM. Tuesday’s First Quarter Moon rises at 2:42 PM, in the Southeast, slightly smaller, 49% lit and sets at 11:09 PM.

Venus continues to be the “Evening Star”. It rises in Scorpius and, by 7 PM, it blazes with minus 4th magnitude, appears 20 arc-seconds, 57% lit and 9° high in the Southwestern sky. Venus sets at 8:04 PM. Before it gets too low, the observer should look a bit to Venus’ left where the star Antares dwells. Antares is a giant star which serves as the heart of the Scorpion; shining with 1st magnitude, it also is a variable star and was named because it is colored like Mars. Binocular or telescope users can compare and contrast the two before they set.

Once observers are finished with Venus and Antares, they should swing South, where Capricornus contains both Saturn and Jupiter. Saturn rises first, glowing with zero magnitude, 17 arc-seconds, highest at 8:09 PM and sets at 12:56 AM. For months we have saying the Saturn is in retrograde; now it appears to stop dead in its tracks and soon begins an apparent eastward movement.

Jupiter is next, 15° to Saturn’s left, glimmering with minus 2nd magnitude, appearing over twice Saturn’s size, 25° high by 8 PM, highest at 9:11 PM and sets at 2:26 AM. Binocular observers can easily see Jupiter’s 4 moons. Telescope users can witness the moon Io begin to cross Jupiter’s face at 11:09 PM Monday. Io’s shadow creeps into view at 12:16 AM on Tuesday; Io exits at 1:26 AM and the shadow follows at 2:33 AM. However, these last two phases will probably be too low for most local observers.

Third place Neptune lies in Aquarius, glowing with 7th magnitude, a tiny 2 arc-seconds, 18° high at 8 PM, highest at 11 PM and sets at 4:45 AM. It is found 28° to Jupiter’s left. Uranus brings up the rear, in Northeast Aquarius. It rises at 7:17 PM, shines with 5th magnitude, a slightly larger size of 3 arc-seconds, 7° high at 8 PM and sets during daytime. Neptune is up most of the night and Uranus is a naked eye object if the observer is in a dark, rural area.

Note that the Moon, Saturn, Jupiter, Neptune and Uranus form a celestial chain for most of the night.

Monday is Columbus Day. Most people are familiar with the story of Columbus sailing West to reach China. When he landed in the Caribbean, he thought he had found Japan. How could he have made that mistake? Finding latitude is easy, sight on the Pole Star and measure its height above the horizon. But longitude could not be calculated without very accurate sea-borne clocks; which were not invented for another 300 years. Two ancient Greeks measured the Earth. Eratosthenes accurately estimated the Earth’s diameter; Claudius Ptolemy underestimated it. Arab scholars provided other studies of Earth’s size. They used a shorter Arabian mile, which Columbus mistook to be equal to nautical miles. Using “dead reckoning,” a navigational estimation of a ship’s course, it was natural for Columbus to think he circumnavigated the Earth and landed on Japan.

Skywatch Line for Friday, October 8, through Sunday, October 10, 2021

This is Dudley Observatory’s Skywatch Line for Friday, October 8, through Sunday, October 10, written by Sam Salem.

On Friday, Sun rises at 7:01am and sets at 6:24pm; Moon rises at 9:31m and sets at 7:51pm.

On Friday night, Spot Venus low in the southwest as early in twilight as you can. Then look lower right of it by some 12 degrees, or about a fist at arm’s length, for the thin crescent Moon. The Moon is at perigee on Friday, so it will appear a trace larger than average, or a super crescent Moon.

On Saturday, the Moon shines only about 3 degrees above Venus in twilight, just while Venus is passing ¾ degrees lower left of 2nd-magnitude Delta Scorpii. As the sky darkens after sunset, watch the southwestern sky for the pairing of the slim crescent Moon shining just above very bright Venus, easily close enough for them to share your binoculars’ field of view. Try to spot the Moon in late afternoon and try to see Venus’ bright speck below it in daytime, even without binoculars. Once the sky darkens, after about 7:30pm, the fainter claw stars of Scorpius will appear around the Moon and Venus. Venus, at magnitude –4.3, shines low in southwest during twilight, in the constellation of Libra. It sets a little after twilight’s end.

The Draconids meteor showers are short-lived. Watch these meteors at nightfall and early evening of Friday. You might catch some on the nights before and after as well. Fortunately, the thin waxing crescent Moon sets before nightfall and won’t hinder this year’s Draconid shower. The radiant point for the Draconid meteor shower almost coincides with the head of the constellation Draco the Dragon in the northern sky. The radiant point of the meteor shower stands highest in the sky as darkness falls. That means that, unlike many meteor showers, more Draconids are likely to fly in the evening hours than in the morning hours after midnight. This shower usually produces only a handful of languid meteors per hour in most years. In rare instances, fiery Draco has been known to spew forth many hundreds of meteors in a single hour.

On Friday, the dwarf planet Ceres will cease its eastward motion across the stars of the constellation of Taurus. The next nights, Ceres will begin a westward retrograde loop that will last until mid-January. In late evening, the magnitude 8.2 dwarf planet will be located low in the eastern sky, several finger widths to the lower left of the Bull’s brightest star Aldebaran.

Jupiter and Saturn continue to shine in the southeast to south during evening. They sit 16 degrees apart on opposite sides of dim constellation of Capricornus. By the end of twilight, they sit equally high in the south-southeast. As evening progresses watch them tilt to the right, with Saturn the lower one. Saturn sets around 2am, followed by Jupiter about an hour later.

Skywatch Line for Wednesday, October 6, and Thursday, October 7, 2021

This is Dudley Observatory’s Skywatch Line for Wednesday, October 6, and Thursday, October 7, written by Alan French.

The Sun sets at 6:28 P.M. on Wednesday and rises at 7:00 A.M. Thursday. Sunset Thursday is at 6:26 and the Sun will rise at 7:01 on Friday.

The Moon reached new at 7:06 A.M. Wednesday and is moving toward first quarter, which it will reach at 11:25 P.M. on Tuesday, October 12. The Moon sets soon after sunset and the night skies will be dark and moonless Wednesday and Thursday.

Have you noticed how Venus has been moving farther south in the evening sky, now shining brightly at magnitude -4.2 in the southwest during evening twilight? When Venus is in the evening sky it lies east of the Sun, and it will continue moving farther east through October 29, when it will be 47-degrees from the Sun.

Venus, traveling on its faster, inner orbit around the Sun, is now catching up with our Earth. Because it orbits between us and the Sun, it exhibits phases like our Moon. It is now just under 60% illuminated, appearing like a tiny waning gibbous Moon through a telescope. As it slowly catches up with Earth, we see less and less of its sunlight face. As our Moon moves from full to new, it grows fainter each night, yet Venus will continue to grow brighter until December 3, when it reaches magnitude -4.9.

The reason for this discrepancy is simple. The Moon, varying little in its distance from Earth, remains essentially the same size in our sky, but Venus, while catching up with us, is also moving closer, and its apparent size is increasing. For part of its journey, the increase in apparent size more than makes up for the smaller part of its visible face in sunlight.

At its current 60% illumination, Venus is 126 million km away and appears 19.8 arcseconds in diameter. On December 3, when it will be brightest, it will be 61.4 million kilometers away, and appear 25.5% in sunlight and 41.2 arcseconds in diameter. After December 3 the increase in apparent diameter will no longer quite make up for the smaller portion of the planet’s visible disk in sunlight, and the waning crescent Venus will slowly fade slightly, reaching magnitude -4.7 on December 21.

By 9:00 P.M. Jupiter and Saturn will be nicely placed in the south. Jupiter, at magnitude -2.7, will be 30-1/2 degrees high and a bit east of due south. Saturn, at magnitude +0.5, will be west of due south and 27-1/2 degrees high.

Even a modest telescope will show the four bright Galilean moons of Jupiter, appearing as stars to either side of the planet. At 9:00 P.M. Wednesday Europa will be to the east of Jupiter, and Io, Ganymede, and Callisto, will be stretched out to the west. At 9:00 P.M. on Thursday Io will be to the east, with Europa and Ganymede close together and not far from the planet’s limb, to the west, and Callisto, in its slower, outer orbit, still well to the west.

Jupiter now has 79 known moons, and no others are visible in modest amateur telescopes. If you spot what looks like an extra moon, it is a background star.

Skywatch Line for Monday and Tuesday October 4th, and 5th, 2021

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday October 4th, and 5th, written by Joe Slomka.

The Sun sets at 6:31 PM; night falls at 8:05. Dawn begins at 5:24 AM and ends with the Sun rising at 6:58.

Monday’s Moon rises at 4:28 AM in Leo, 32 arc-minutes in size, and sets at 6:05 PM; this is the Old Moon which poses a challenge to the observer to spot a thin 3% crescent in the brightening sky. Tuesday’s New Moon now inhabits Virgo, but is not visible, hiding in the Sun’s glare.

The variable star Algol, in Perseus, is at its dimmest at 11:23 PM on Tuesday, 41° up in the East.

The Zodiacal Light, faint glowing of our Solar System’s dust, will be visible for the next two weeks. In the pre-dawn rural sky, it appears like a pyramid stretching from southeastern Cancer to Taurus.

Venus is still the “Evening Star”, hanging low in the western sky and setting at 8:09 PM. This month, Venus approaches Earth. Binoculars and telescopes reveal that it sets progressively later and brighter. Its apparent size becomes bigger, from 19 arc-seconds to 26 arc-seconds, but its crescent decreases from 62% to 48% lit.

Once you are finished observing Venus, swing eastward to see Saturn and Jupiter already well up in southeastern Capricornus. Saturn rises first, shines with zero magnitude, 17 arc-seconds, 24° high by 7 PM, highest at 8:37 PM, and sets at 1:24 AM. Brilliant Jupiter, is next. It blazes with minus 2nd magnitude, almost 46 arc-seconds, 21° high by 7 PM, highest at 9:40 PM and sets at 2:45 PM. Tuesday, telescopic viewers can witness the Jovian moon Io begin to cross the planet’s face at 9:19 PM, followed by its shadow at 10:20. The whole event ends with the shadow leaving at 4:38 AM. This month, both planets are still in retrograde, which means that they are backing up, but will stop and begin to creep closer to each other.

Neptune, next, lies 28° to Jupiter’s left. In Aquarius, it glows with 7th magnitude, a tiny 2 arc-seconds, highest at 11:28 PM and sets at 5:14 AM. Uranus, bringing up the rear in Aries, rises at 7:46 PM, shines with 5th magnitude, almost 4 arc-seconds, highest at 2:48 AM and sets during daytime. Beginners should obtain sky charts from astronomy magazines or apps.

Since both Saturn and Jupiter inhabit Capricornus, let us contemplate this unusual constellation. By nightfall, Capricornus, Aquarius, Pisces and Cetus dominate the southern sky. All are water-based. Capricornus is a unique constellation: The Sea-Goat. The creature has the head of a goat, but the body of a fish. This part of the Zodiac is truly ancient; Sumerians identified it as early as 1600 BC. A royal seal, from the town of Ur, is on display in the Boston Museum. The seal bears the image of Capricornus, just as it is pictured today. Boundary markers of Mesopotamian kings also depict Capricornus as we do. The source of this animal is a mystery. A people far removed from any large body of water invented it. The Goat-Fish was associated with the god Ea, the master of creation and the god of the underwater seas, including fresh water springs. Ea resembles the Roman god Neptune. In 1846, the astronomer Galle discovered Neptune in Capricornus.

The constellation inspired several English words. To caper is to frolic like a goat; when people change their minds, they are called capricious. The famous island of Capri was named “the isle of goats.” Cornucopia is a horn of plenty.

Skywatch Line for Friday, October 1, through Sunday, October 3, 2021

This is Dudley Observatory’s Skywatch Line for Friday, October 1, through Sunday, October 3, written by Sam Salem.

On Friday, Sun rises at 6:53am and sets at 6:36pm; Moon rises at 1:00am and sets at 4:37pm. Before and during early dawn Saturday morning, look below the crescent Moon by about a fist at arm’s length for Regulus, forefoot of the constellation of Leo the lion. Before and during early dawn Sunday morning, the waning crescent Moon forms a flat, almost isosceles triangle, with Regulus and Algieba, or Gamma Leonis, to Regulus’s left or upper left.

Venus, brilliant at magnitude –4.2, shines low in the southwest during twilight. It sets around twilight’s end.

Jupiter, at magnitude -2.7, and Saturn, at magnitude +0.5, continue to shine in the southeast to south during evening. They sit 16 degrees apart on opposite sides of the dim constellation of Capricornus. During twilight, bright Jupiter, on the left, is slightly the lower of the two. They level out soon after dark, and later they tilt the other way, with Saturn now the lower one. Saturn sets around 2am, followed down by Jupiter about an hour later. In the evening look for 1st-magnitude Fomalhaut, two fists lower left of Jupiter.

Vega is the brightest star just west of the zenith after dark. Face west and look to Vega’s right, nearly a fist and a half at arm’s length, for Eltanin, the nose of Draco the Dragon. The rest of Draco’s fainter, lozenge-shaped head is a little farther behind. Draco always eyes Vega as they wheel around the sky. The main stars of Vega’s own constellation, Lyra, are faint by comparison. They extend about 7 degrees to Vega’s left.

Vega is the brightest star very high in the west. Arcturus, the brightest star in the constellation of Boötes, is getting low in the west-northwest. The brightest star in the vast expanse between Vega and Arcturus, about a third of the way from Arcturus up toward Vega, is Alphecca. The magnitude 2.2 star is the crown jewel of the small, dim constellation of Corona Borealis, the northern crown. Alphecca is a 17-day eclipsing binary. The periodic eclipses result in a magnitude variation of 2.21 to 2.32, which is hardly noticeable to the unaided eye.

During evening, look just above the northeast horizon, far below high Cassiopeia, for bright Capella on the rise. Capella, the brightest star in the constellation of Auriga, is the third brightest star in the northern celestial hemisphere after Arcturus and Vega. Its name meaning “little goat” in Latin.

The Big Dipper is perhaps the most famous of all star patterns. For latitudes of 41 degrees North or farther North, The Big Dipper is circumpolar, or always above the northern horizon. For latitudes below 41 degrees, the Big Dipper is below horizon during the evening hours in the autumn. For our area, look for the Big Dipper shining way up high in the sky on spring evenings, but close to the horizon on autumn evenings.

Skywatch Line for Wednesday, September 29, and Thursday, September 30, 2021

This is Dudley Observatory’s Skywatch Line for Wednesday, September 29, and Thursday, September 30, written by Alan French.

The Sun sets at 6:40 P.M. on Wednesday and rises at 6:52 A.M. Thursday. Sunset Thursday is at 6:38 and the Sun will rise at 6:53 on Friday.

The Moon reached last quarter this past Tuesday night and is now headed toward new. It will reach new on Wednesday morning, October 6. The Moon rises at 11:55 P.M. Wednesday night and after midnight on Thursday, rising at 12:57 A.M. Friday morning.

On Thursday morning at 5:00 A.M., the waning crescent Moon, 37% illuminated, will be in the constellation Gemini, not far from the constellation’s brightest stars, Castor and Pollux. The Moon will be high in the east, with Pollux 3-degrees to its left and Castor a little over 6-degrees away to the upper left.

By Friday morning the Moon’s eastward motion among the stars will have it in Cancer. Now 28% illuminated the Moon will be just under four degrees from the famous Beehive Cluster, an open cluster of stars known since ancient times. It is easily seen by eye under dark, moonless skies, but binoculars will reveal it in spite of the competition of the Moon. Look for it to the lower right of the Moon, at about the 5 o’clock position. In a week, with the Moon out of the way, you try the Beehive Cluster by eye.

While the ISS (International Space Station) is brightest and most impressive when it passes high overhead, it’s easily visible when it’s lower in the sky. Wednesday and Thursday provide chances to watch it pass across the northern sky, and both passes will have the ISS move into the Earth’s shadow and fade from view..

On Wednesday night look for the ISS moving up from the northwestern horizon at 8:32 P.M. It moves slowly at first and is dimmed by the thick atmosphere near the horizon, so you may not spot it right away. By 8:34 it will be approaching the back of the Big Dipper’s bowl. It will pass through the Big Dipper and then below the Little Dipper. As it moves below Polaris, the North Star, it will move into the Earth’s shadow and fade from view. How far can you follow it before it completely vanishes from view?

Thursday night’s pass will cross more of the northern sky before moving into the Earth’s shadow. Look for the ISS coming up from the northwestern horizon at 7:45 P.M. Passing a little lower in the sky than Wednesday, it may take longer to first spot the space station. At 7:47 is will be passing just below the Big Dipper’s bowl. Just after 7:48 it will be due north and passing below Polaris. At 7:49 it will pass below the familiar “W” pattern of stars marking the constellation Cassiopeia, the Queen. Just after 7:50, as it moves toward the horizon, it will move into the Earth’s shadow and fade from view.