Skywatch Line for Friday, October 19 through Sunday, October 21, 2018

This is Dudley Observatory’s Skywatch Line for Friday, October 19 through Sunday, October 21, written by Sam Salem.

On Friday, the Sun rises at 7:14am and sets at 6:07pm; the waxing gibbous Moon sets at 1:47am and rises at 4:07pm. Neptune sits 3 degrees north of the Moon on Saturday.

Look for Jupiter, at magnitude –1.8, as early as possible in evening twilight. It hovers just 5 degrees above the southwest horizon. Saturn and Mars are also visible at the same time and much easier to appreciate. Saturn shines at magnitude 0.5 and sits some 20 degrees above the southwest horizon. Mars gleams in the south-southeast at magnitude –0.9. It climbs to the meridian a little before 9pm.

On Sunday during the predawn hours, the Orionid meteor shower reaches its peak. This year, a waxing gibbous Moon will interfere with meteor watching. The best time to look will be after moonset and before the start of morning twilight, roughly between the hours of 4am and 6am The advantage of watching the meteor shower late Friday to Saturday morning, rather than the following nights is that there is less moonlight to obstruct the show. The Moon sets roughly 4 hours before sunrise on Saturday, however, it sets only about 2 hours before sunrise on Monday. The radiant point for the Orionids is in the northern part of constellation Orion, near Orion’s club. The radiant point lies between Betelgeuse and the eastern “foot” of Gemini. The meteors appear in all parts of the sky. But if you trace the paths of the meteors backwards, you’ll see they all seem to come from the Orion constellation. The shower offers perhaps 10 to 15 meteors per hour in a dark sky. This is a modest display made up of debris shed by Comet Halley. The Orionid meteor shower is the second meteor shower created by Comet Halley. The Eta Aquarids, in May, is the other meteor shower created by debris left by the comet. Halley takes around 76 years to make a complete revolution around the Sun. It will next be visible from Earth in 2061.

Arcturus, in the constellation Bootes, the Herdsman, shines in the west to northwest after sunset. Arcturus adorns the western evening sky all through October. Arcturus is one of three stars noticeable for flashing in colors at this time of year. The arc of the Big Dipper handle extended outward always points to orange-colored Arcturus. Capella, in the constellation Auriga, the Charioteer, is the second star. It sits now in the northeast in mid-evening. Sirius, in the constellation Canis Major, the Greater Dog, is the third flashing star of the season. It sits in the south before dawn. All three stars appear to be flashing colors for the same reason. All three stars are bright and noticeably low in the sky at this time of year. Objects low in the sky are seen through a greater thickness of atmosphere than when they are overhead. The atmosphere refracts or splits the stars’ light to cause these stars to flash in the colors of the rainbow.

Skywatch Line for Wednesday, October 17th, and Thursday, October 18th, 2018

This is the Dudley Observatory Skywatch Line for Wednesday, October 17th, and Thursday, October 18th, written by Louis Suarato.

The 60% illuminated, waxing gibbous Moon rises at 2:58 p.m. Wednesday. The Moon reaches apogee, its furthest distance from Earth during this lunar cycle, Wednesday at 3:16 p.m., at a distance of 251,175 miles. At twilight, look 6 degrees to the left of the Moon for Mars. Both Moon and Mars will be 27 degrees above the southern horizon at 8 p.m. in the constellation Capricornus.

Capricornus is a dim constellation, with only one star brighter than 4th magnitude. The brightest star in Capricornus is Delta Capricorni, also known as Deneb Algedi, meaning “the tail of the goat” in Arabic. Deneb Algedi is 39 light-years away, and shines at magnitude 3.6. On nights without the Moon nearby, look for globular cluster M30 within Capricornus. Discovered by Charles Messier in 1764, M30 is 27,100 light-years from Earth, and estimated to be 12.93 billion years old. This 7.70 magnitude, slightly oval star cluster can be seen with a small telescope during good viewing conditions.

Thursday night, look to the lower right of the Moon for Mars. Look 10 degrees to their lower left for Fomalhaut, “the Autumn Star”. Try to see Jupiter before it sets at 7:32 p.m. in the south-southwest. Saturn remains in the sky until setting at 9:56 p.m. in Sagittarius. Mercury and Venus are hidden by the glare of the Sun.

The Albany Area Amateur Astronomers invite you to join them at their monthly meeting to be held at miSci, Thursday, beginning at 7:30 p.m. in Schenectady. The guest speaker will be Dr. Karyn Lynne Rogers, Assistant Professor at RPI in the School of Sciences, Department of Earth and Environmental Sciences. Dr. Rogers will discuss “Habitability through Space and Time”. Her research consists of microbial life and environmental conditions in extreme ecosystems. Dr. Rogers is a member of the New York Center for Astrobiology and the Institute for Data Exploration and Applications.

Skywatch Line for Monday and Tuesday, October 15th and 16th, 2018

This is the Skywatch Line for Monday and Tuesday, October 15th and 16th.

The Sun sets at 6:13 PM; night falls at 7:47. Dawn begins at 5:35 AM and ends with the Sun rising at 7:10.

Bright planets are becoming scarce in the evening sky. Jupiter, in Libra, blazes with minus 1st magnitude only 13º above the southwestern horizon. It is too low now for sharp images of its cloud systems and sets at 7:41 PM.

Saturn, in Sagittarius, lies due South. It shines with zero magnitude and appears about half Jupiter’s size. At about 24º high, it is high enough to enjoy the planet’s ring system. Saturn sets at 10:06 PM.

Mars, in Capricornus, glows with minus 1st magnitude, appears about 87% illuminated and 13 arc-seconds in size. Recent NASA reports indicate that the planet-wide dust storm continues to abate, making observations of its surface easier. On Tuesday, the northern Martian hemisphere experiences its winter solstice. Mars is moderately low and is best seen at 9:21 PM. It sets at 1:06 AM.

As twilight ends, Neptune, in Aquarius, shines dimly with 7th magnitude and 2.3 arc-seconds in size. It lies about 29º high in southeastern skies, is best observed at 10:20 PM and sets at 3:55 AM. Uranus rises at 6:28 PM in Aries, shines at 5th magnitude and appears slightly larger than Neptune. Uranus is ideally situated at 1:12 AM.

The Moon inhabits Sagittarius both nights. Monday, it blazes at minus 9th magnitude and appears about 43% lit. Due South at Sunset, it sets at 11:01 PM. Tuesday’s First Quarter Moon appears about 52% illuminated and is slightly brighter. Best observed at 7:04 PM, it sets at 11:52 PM.

Rising after Midnight, Comet Giacobini-Zinner is best observed around Astronomical Dawn. Glowing with 8th magnitude the comet is located near the Monoceros-Canis Major border. The 4th magnitude star Gamma Canis Majoris (Muliphein) is the closest bright star.

The Solar System has an unusual arrangement. Rocky bodies (Mercury, Venus, Earth, Mars and the Asteroid Belt) lie close to the Sun. Gas giant planets (Jupiter, Saturn, Uranus and Neptune) comprise a second group. Finally, there are the icy objects (Pluto, Eris and the rest of the Kuiper and Oort Belts). Uranus and Neptune are very similar. Unlike Jupiter and Saturn, they are made of mostly hydrogen compounds like water, methane and ammonia. Methane is what gives these planets their blue tint. These planets are mostly gas with rock and metal cores. Both planets rotate about every 16 or 17 hours. Since they are mostly gas, rotation varies by latitude; the equator spins faster than the poles. Uranus has four medium moons; Neptune has two. Uranus has no obvious weather. Neptune occasionally sports a “Great Dark Spot,” similar to Jupiter’s Great Red Spot. Uranus emits no heat, while Neptune glows with twice the energy it receives from the distant Sun. Both planets have rings, which can only be seen through the Hubble Telescope or passing space probes.

Skywatch Line for Friday, October 12 through Sunday, October 14, 2018

This is Dudley Observatory’s Skywatch Line for Friday, October 12 through Sunday, October 14, written by Sam Salem.

On Friday, the Sun rises at 7:05am and sets at 6:18pm; the waxing crescent Moon rises at 10:41am and sets at 8:48pm. On Sunday evening, the crescent Moon approaches Saturn.

Jupiter, at magnitude –1.8, is viewable for only a short while this weekend. It shines low in the southwest and sets roughly 1½ hours after the Sun. Saturn, at magnitude 0.5, is a little past the meridian 45 minutes after sundown. Saturn is easy to spot in northern Sagittarius. East of Saturn is Mars, at magnitude –1.1, near the center of the V-shaped constellation Capricornus. Mars is now considerably fainter and smaller. Mars still offers some good telescopic views. The best time to look is when Mars is at the meridian, around 9pm.

This weekend, watch two of the finest autumn globular clusters, M15 in constellation Pegasus, and M2, nearby in constellation Aquarius. Both globulars can be spotted in binoculars. M15 is easy to locate just northwest of the 2.4-magnitude star Enif, or ε Pegasi. M2 sits north of 2.9-magnitude Beta (β) Aquarii.
In a telescope, each cluster appears nicely symmetrical with a bright, highly concentrated core surrounded by a fringe of faint stellar haze. Both clusters are at magnitude 6.2 and span roughly 12 arc-minutes. However, with thorough observation you will find out that these globulars are not identical.

Use the Summer Triangle and the constellation Cygnus, the Swan, to locate the galactic equator, the great circle on the celestial sphere that bisects the glowing band of stars of the Milky Way. It’s the autumn season, but the three brilliant stars that make up the Summer Triangle still shine in our sky. They sit way up high on October nights. The stars Deneb and Vega hang high overhead at nightfall and early evening. Vega, the brightest Summer Triangle star, shines to the right of Deneb, and Altair, the second brightest, is found roughly halfway between southern horizon and straight overhead. As evening deepens, look for a star to pop out in between Altair and Vega. That’s Albireo. It depicts the Swan’s eye or beak. The line from Albireo to Deneb shows the underside of the Swan’s body from head to tail. Three stars cross the body near Deneb to form what is known as the Northern Cross. Go one star farther out on each side of the Northern Cross to finish off the Swan’s wings. Extend the Albireo to Deneb line in either direction to mark the galactic equator. Through binoculars, you’ll see that star clouds, star clusters and nebulae abound on this great galactic line.

Starting Saturday morning, the zodiacal light should be visible in the predawn as a faint, extended glow stemming from the east horizon. Zodiacal light is produced by sunlight reflecting off dust particles in the Solar System. Zodiacal light is best seen during twilight after sunset in spring and before sunrise in autumn, when the zodiac is at a steep angle to the horizon. However, the glow is so faint that moonlight and light pollution outshine it.

Skywatch Line for Wednesday, October 10th, and Thursday, October 11th, 2018

This is the Dudley Observatory Skywatch Line for Wednesday, October 10th, and Thursday, October 11th, written by Louis Suarato.

The 4% illuminated, waxing crescent Moon sets at 7:42 p.m. Wednesday. Look 13 degrees to the Moon’s southwest for Jupiter. Thursday night, Jupiter will be just 4 degrees below the Moon, within the constellation Libra. Mars and Saturn are separated by 40 degrees, about 20 degrees above both sides the southern azimuth after sunset. While Saturn is surrounded by nebulae and star clusters in Sagittarius, Capricornus is devoid of deep sky objects around Mars. Look toward the constellation Leo, which rises after 9 p.m., for the Southern Taurid meteor shower. This meteor shower only yields 5 meteors per hour, but is notable for bright fireballs in certain years. What you will see burning up in Earth’s atmosphere are the dusty particle debris from Comet 2P/Enke. Comet Enke is a periodic comet that completes an orbit around the Sun once every 3.3 years. It was discovered in 1786 by French astronomer Pierre Mechain. Comet Enke’s next closest approach to the Sun will be June 25, 2020.

Wednesday night, an extremely bright International Space Station will fly over our region. You can see the ISS with the unaided eye by looking toward the west-northwest horizon at 7:32. The ISS will sail very close to globular cluster M3 before passing Bootes brightest star, Arcturus, and continuing on through Hercules, and passing the Great Globular Cluster M13.The ISS will continue on to Aquila, passing close to its brightest star, Altair. The bright spacecraft will cross through Aquarius, and past Mars, before disappearing into the southeast horizon.

Skywatch Line for Monday, October 8th and Tuesday, the 9th, 2018

This is the Skywatch Line for Monday, October 8th – Columbus Day, and Tuesday, the 9th.

The Sun sets at 6:24 PM; night falls at 7:58. Dawn begins at 5:27 AM and ends with sunrise at 7:01.

The procession of bright planets is ending. Jupiter, in Libra, is the brightest, at minus 1st magnitude. It is moderately low in the southwestern sky at 10º high. Jupiter sets at 8:04 PM.

Moving East, Saturn still resides in Sagittarius, shines with zero magnitude and is a moderate 16 arc-seconds in size. During Civil Dusk, it is moderately high at 23º, affording viewers last looks at the magnificent ring system. Saturn sets at 10:31 PM.

Mars, also still inhabits Capricornus. Now pulling away from Earth, it appears about 87% lit and shines with minus 1st magnitude. NASA reports that the dust storm continues to abate and some areas are observable. Mars is best observed at 8:36 PM and sets at 1:15 AM.

Neptune, near the star “h Aquarii”, glows with 8th magnitude and appears a tiny 2.3 arc-seconds in size. It is highest and best observed at 10:48 PM and sets at 4:24 AM. Uranus, 3º from the star Omicron Piscium, rises at 6:56 PM and is 11º high at Civil Dusk. It shines with 5th magnitude and is 3.4 arc-seconds in size. Uranus is best observed at 1:41 AM and remains up past sunrise. Both planets require detailed star charts from astronomical media.

The Moon is “New” Monday night, and rises in Virgo at 7:18 AM Tuesday, and sets at 7:07 PM.

If observing about Midnight Monday and spot meteors coming from the area of the Little Dipper (Ursa Minor), you are witnessing the Draconid meteor shower. The shower peaks Monday night. This is an irregular event, most times it is very sparse, but sometimes (1936 & 1946) thousands were observed. The Draconids, like most meteor showers, originate from debris left by comets. Comet 21/P Giacobini-Zinner is not only the progenitor of the meteor shower, it is prominent in our skies now. The meteors seem to slowly flow from the head of Draco, the constellation that wraps itself around the Pole Star. The famous Peekskill meteor that totaled a car may have originated from this shower.

Comet Giacobini-Zinner is currently at its brightest in our skies; it reaches perihelion Tuesday night. In the constellation Monoceros, near the border with Canis Major, it shines with 8th magnitude, making it easily visible in telescopes and possibly binoculars. Giacobini-Zinner is up virtually all night. Since its arrival coincides with the annual Draconid meteor shower, there is some possibility of an enhanced shower. Again, detailed charts from astronomical media assist location.

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; such clocks were not invented for another 200 years. Two ancient Greeks measured the Earth. Eratosthenes accurately estimated the Earth’s diameter; Claudius Ptolemy underestimated it. Arab scholars provided other approximations of Earth’s size. They used a smaller Arabic 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 mistake the island of Jamaica for Japan.

Skywatch Line for Friday, October 5 through Sunday, October 7, 2018

This is Dudley Observatory’s Skywatch Line for Friday, October 5 through Sunday, October 7, written by Sam Salem.

On Friday, the Sun rises at 6:57am and sets at 6:30pm; the waning crescent Moon rises at 2:30am and sets at 4:56pm. The new Moon occurs on Monday at 11:47pm.

Jupiter’s current apparition is nearly over. It hovers at magnitude –1.8, less than ten degrees above the southwest horizon 45 minutes after sunset. Saturn, shining at magnitude 0.5, is positioned a little west of the meridian. Mars glows at magnitude –1.2 from western constellation Capricornus. The Martian disk is considerably smaller than it was at its peak this summer. It has shrunk from 24.3 arc-seconds down to its current diameter of 15.3 arc-seconds.

Venus is heading directly into the Sun’s glare. During the first week of October Venus becomes lost from view from mid-Northern latitudes. Venus reaches its stationary point in Southwestern constellation Libra this Friday. The planet then commences retrograde, East to West motion, turning back towards constellation Virgo and re-entering that constellation at its extreme Southeastern corner on Monday.

This moonless weekend is an opportunity to spot Uranus with your naked eyes. Uranus, at magnitude 5.7, sits near the Aries-Pisces constellations border. It is easy to find with binoculars if you have a finder chart and know the constellations well enough. Uranus rises around 7:09pm on Friday, reaching transit altitude of 59 degrees south at 1:58am.

The constellations of summer and fall lie within reach before midnight. One summer object currently in prime position at nightfall is the Ring Nebula M57 in constellation Lyra. The Ring nebula is relatively bright, glowing at magnitude 8.8. However, the nebula spans only 70 arc-seconds, which is slightly less than twice the apparent size of Jupiter. Fortunately, M57’s location is easy to find. It is situated between the stars Lambda (λ) and Beta (β) Lyrae, a little closer to Beta than Lambda. Small telescopes used at low magnification will show the tiny, ghostly disk. With higher power you will be able to see the dark central hole that gives the Ring its name.

Spot Vega with your naked eyes before sunset this weekend. Vega reaches transit altitude of 86 degrees south, a few minutes after sunset, around 6:35pm on Friday. Vega is the brightest star very high in the west right after nightfall. Arcturus, equally bright, is getting low in the west-northwest. The brightest star in the vast expanse between them, about a third of the way from Arcturus up toward Vega, is Alphecca, at magnitude 2.2. Alphecca, the crown jewel of Corona Borealis, is a 17-day eclipsing binary. However, its brightness dips are too slight for the eye to see.

This is the Dudley Observatory Skywatch Line for Wednesday, October 3rd, and Thursday, October 4th, 2018

This is the Dudley Observatory Skywatch Line for Wednesday, October 3rd, and Thursday, October 4th, written by Louis Suarato.   The 34% illuminated, waning crescent Moon sets at 3:34 p.m. Wednesday. Look for M44, the Beehive Cluster, 1 degree to the upper left of the crescent Moon before Thursday’s sunrise.. At approximately 600 light-years away, the Beehive Cluster is one of the closest open star clusters. M44 contains about 1,000 gravitational bound stars, estimated to be about 600 million years old. After sunset, Mars, Saturn, and Jupiter can be seen spanning 77 degrees from above the south-southeastern to the west-southwestern horizons. Venus and Mercury are too close to the Sun to see, with Venus heading toward the Sun, and Mercury moving away. Mercury will re-emerge in the evening sky during mid-month. Venus will reappear in the morning sky early next month.

While you are out looking at the crescent Moon during the early morning twilight, look to the south, or right of the Moon, about 25 degrees to Canis Minor’s brightest star, Procyon. Then scan another 25 degrees to Comet 21P/Giacobini-Zinner. This 7thmagnitude comet is to the upper left of Sirius, the brightest star in our sky. Another comet to keep track of is 41P/Wirtanen. This comet, discovered in 1948, returns for its trip around the Sun once every 5.4 years. In December, Comet 41P/Wirtanen will reach perihelion, its closest approach to the Sun, days before reaching its closest approach to Earth. The comet may reach 3rdto 6th magnitude during December.

On October 4, 1957, the Space Race began when the Soviet Union launched the satellite Sputnik-1 into Earth orbit. Traveling at 18,000 miles per hour, Sputnik completed 1,440 orbits in 3 months, about 43 million miles, before burning up in Earth’s atmosphere. Since then, 8,100 satellites have been launched by 40 countries. About 4,900 remain in orbit, with 1,900 that remain operational. The largest, and only habitable artificial satellite, is the International Space Station. The ISS is visible with the naked eye, and can be seen Thursday, beginning at 7:53 p.m. when it emerges from the northwest horizon. This -2.1 magnitude pass will sail past the bowl of the Big Dipper before disappearing into Earth’s shadow before reaching the constellation Perseus.

Weather permitting, the Albany Area Amateur Astronomers will host star parties this Friday and Saturday nights at the Landis Arboretum in Esperance, NY. Non-members are welcome as our amateur astronomers share views of planets, galaxies, nebulae, star clusters, and asterisms through their telescopes. It is also a great opportunity to test various telescopes before buying one of your own, or gaining insight on using one you may have recently obtained.

This is the Skywatch Line for Monday and Tuesday, October 1st and 2nd, 2018

This is the Skywatch Line for Monday and Tuesday, October 1st and 2nd.  The Sun sets at 6:36 PM; night falls at 8:10. Dawn breaks at 5:19 AM and ends with the Sun rising at 6:53.

The planetary parade is ending. While we see four bright planets during civil dusk, two are gone shortly after sunset.

Venus, in Libra, the brightest at minus 4th magnitude, lies very low on the western horizon. As it approaches Earth, it grows in size to 47 arc-seconds, but its disk shrinks to 16% illuminated. At civil dusk, it is only one degree high, which means that the observer should seek an unobstructed horizon. Venus sets at 7:14 PM.

Jupiter, also in Libra, is next brightest at minus 1st magnitude, and moderately low in the southwest at 12º altitude and 32 arc-seconds in size. Telescopic observers can witness the Jovian moon IO begin to cross the planet’s face at 7:41 Monday night; Tuesday can see it reappear at 8:01 PM. However, these events occur when the planet is quite low. Jupiter sets at 8:28 PM.

Looking eastward, Saturn, in Sagittarius, glows with 5th magnitude. This month, it dims slightly and shrinks to 16 arc-seconds in size. At about 24º high in the south, it is high enough for enjoyable views of its ring system. The Cassini space probe orbiting Saturn recently made a startling discovery: a dust storm on the moon Titan. Up until now, Mars was the only planet, besides Earth, that exhibited dust storms. Titan’s storm originated in the equatorial dunes and went planet-wide. However, unlike Earth and Mars, Titan’s atmosphere is a mix of methane and ethane, not oxygen and water. The Ringed Planet sets at 10:57 PM.

Mars, in Capricornus, is the night’s last bright planet. It shines at minus 1st magnitude, but fades to .6 at month’s end. In our telescopes, Mars appears about 88% lit and 15 arc-seconds in size. Civil dusk finds it 20º high in the East. Mars is best observed at 8:51 PM and sets at 1:25 AM.

Neptune rises in Aquarius at 5:40, glows with 7th magnitude and appears a tiny 2 arc-seconds in size. It is highest at 11:16 PM, when it is best observed; it sets at 4:57 AM. Uranus, rises in Aries at 7:24 PM, shines with 5th magnitude and is 3 arc-seconds in size. By Midnight, it is 47º high in the south and is best observed at 2:09 PM. Both planets lie in crowded star fields and require detailed charts to aid the observer.

Tuesday, the Moon rises in Gemini at 11:13 PM. At 22 days old, it appears about 52% illuminated and blazes with minus 10th magnitude. Wednesday’s Moon, still in Gemini, is only 38% lit, slightly dimmer at minus 9th magnitude and rises at 12:12 AM.

The Moon may hinder observation of Comet 21P/Giacobini-Zinner. The 7th magnitude comet is located in the dim constellation Monoceros, which lies beneath Gemini. Visible after midnight, the comet is reportedly binocular-visible; astronomical websites provide finder charts.

At nightfall, the Milky Way streams overhead from North to South. Many of the most famous constellations are found along this river of stars: Cassiopeia, Cygnus, Aquila, Sagittarius, also lesser known Delphinus and Scutum. Scutum is located halfway between Aquila and Sagittarius. A bright condensation can be spotted in dark, rural skies. This is the “Wild Duck” cluster. Binoculars show it as a bright knot of stars; telescopes reveal a myriad of stars. Reference books say it contains 2900 stars and is fifteen light years in diameter. This cluster, the eleventh on Messier’s list, is quite close, about 5500 light years away. It shines with the brilliance of 10,000 suns.

This is Dudley Observatory’s Skywatch Line for Friday, September 28 through Sunday, September 30, 2018

This is Dudley Observatory’s Skywatch Line for Friday, September 28 through Sunday, September 30, written by Sam Salem.  On Friday, the Sun rises at 6:50am and sets at 6:42pm; the waning gibbous Moon sets at 10:16am and rises at 9:00pm. Late on Friday evening, spot the Pleiades upper left of the Moon. Try to locate Pleiades’ tiny dipper pattern standing on its handle. On Saturday night, the waning gibbous Moon slowly drifts through the Hyades cluster in constellation Taurus. As it exits the cluster, the lunar disk passes within ½ degree, one Moon diameter, of the constellation’s brightest star Aldebaran. The Moon is nearest Aldebaran around 2am on Sunday Morning.

Venus is at its peak brilliancy of magnitude –4.8, shining very low in the west-southwest after sunset. It sets in late twilight. Venus sits down to Jupiter’s lower right. Their separation remains steady this week at 14 degrees. In a telescope Venus is a crescent, about 25% sunlit and 41 arc-seconds tall. Mars, in southern constellation Capricornus, fades from magnitude –1.5 to –1.3. It shines highest in the south soon after dark and sets around 2am. Jupiter, in constellation Libra, shines at magnitude –1.8 ever lower in the southwest in twilight, upper left of Venus. Saturn is already at the meridian when the Sun sets. Saturn sits in constellation Sagittarius, low in the south. However, Saturn’s magnificent rings will be apparent. The ring system, measured tip to tip, currently appears about as wide as Jupiter’s disk. The rings are tilted toward Earth by an angle of 26 degrees, which is only one degree shy of maximum. This permits easier sightings of the 4,700-kilometre-wide Cassini’s Division gap that separates Saturn’s two brightest rings. During moments of steady seeing, the threadlike feature is visible even in a 60mm refractor.

This weekend look for the loneliest star, Fomalhaut, the bright star located in a region of the sky that contains only very faint stars. Fomalhaut is a bright star in the constellation Piscis Austrinus, the Southern Fish. It is bright enough to be seen on a moonlit night. Fomalhaut rises at 7:26pm and sets at 3:24am, reaching transit altitude of 18 degrees south before midnight on Friday. No other bright star sits so low in the southeast at this time of year. Fomalhaut sits close the southern horizon until well after midnight on these fall nights. Fomalhaut is the brightest white star in an otherwise empty-looking part of the sky. The star is sometimes called the Lonely One, the Solitary One, or sometimes the Autumn Star. Fomalhaut is the 18th brightest star in the sky. The Arabic name, Fomalhaut, means “mouth of the fish” or whale. In 2008, Fomalhaut became the first star with an extrasolar planet candidate imaged at visible wavelengths. The image was published in the journal Science in November 2008. Fomalhaut is the third-brightest star known to have a planetary system, after the star Pollux in the constellation Gemini and our own Sun.