Skywatch Line for Friday, September 22 through Sunday, September 24, 2017

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

On Friday, Sun rises at 6:43am and sets at 6:53pm; the Waxing Crescent Moon sets at 8:29pm. The new Moon occurred on Thursday at 1:30am.

Jupiter, at –1.7 magnitude, is the twilight-only planet this weekend. It sets roughly an hour after the Sun. As twilight begins to fade, Saturn, at 0.5 magnitude, is about 20 degrees high in the southwest. Venus, at–3.9 magnitude, rises before 5 am. Next to appear is Mars, at 1.8-magnitude. The red planet is a relatively faint dot that clears the east horizon at around 5:30 am. A few minutes later, Mercury, appears at magnitude –1.1.

The fall equinox occurs on Friday at 4:02 pm. On equinox, the Sun rises due east and sets due west. An equinox happens when the ecliptic, or Sun’s path, intersects the celestial equator, the imaginary line above Earth’s equator. An equinox occurs when the Sun crosses the celestial equator. No matter where you are on Earth, the celestial equator intersects your horizon at due east and due west. At its highest point in your sky, the celestial equator appears high or low, depending on your latitude. On Equinox day, Sun is midway between the Sun’s lowest path across the sky in winter and highest path across the sky in summer.

Use the Big Dipper to find Polaris, the North Star. Draw a line between the two outer stars in the bowl of the Big Dipper. A line from the two outermost stars in the bowl of the Big Dipper points to Polaris. Polaris marks the tip of the handle of the Little Dipper. The northern sky is a large clock, with Polaris at its center. The hour hand is a line drawn through Dubhe and Merak, the two pointer stars of the Big Dipper. The stars make a full circle in 23 hours 56 minutes instead of exactly 24 hours. Therefore, if you look at the same time each evening, the Big Dipper will appear just a little bit lower in the northwestern evening sky. A month from now at mid-evening, the Big Dipper will be noticeably lower in the northwest.

The faint cone of light known as the zodiacal light extends from the east horizon, upwards along the ecliptic. This weekend is free from moonlight, which makes it one of the best times of year for viewing the zodiacal light. The pale glow of the zodiacal light arises from sunlight scattered by dust particles residing within the inner solar system. Look for an amorphous, cone-shaped luminance in the east before morning twilight begins. Usually, the zodiacal light is only about as bright as the winter Milky Way, which is why you’ll need a dark, clear sky to detect it. You might find the zodiacal light easier to capture with a camera than your eyes. Use a wide-angle lens, aim towards the east, and experiment until you find a combination of aperture, ISO, and exposure time that yields the best results. Set the camera’s white-balance to “daylight” to capture the most natural colors.

Saturday marks the anniversary of Neptune’s discovery. On September 23 1846, the German astronomer Johann G. Galle discovered Neptune after only an hour of searching, within one degree of the position that had been computed by the French astronomer Urbain-Jean-Joseph Le Verrier.

Skywatch Line for Wednesday, September 20th, and Thursday, September 21st, 2017

This is the Dudley Observatory Skywatch Line for Wednesday, September 20th, and Thursday, September 21st, written by Louis Suarato.

The New Moon occurs at 1:31 a.m. Wednesday. The Moon will set as a nearly invisible, .6% illuminated waxing crescent Wednesday evening. You’ll have a better opportunity to welcome the return of the Moon before it sets Thursday as a 3.3% illuminated crescent, in the constellation Virgo. Use binoculars and look about 6 degrees to the left of the crescent Moon for Jupiter as the two set side by side. You’ll have a longer look at Saturn as it appears over the south-southwestern horizon at civil twilight, until it sets at 10:47 p.m. alongside the Teapot asterism.

Wednesday morning, Venus and Leo’s brightest star, Regulus,will be separated by less than 1 degree. Thursday morning, the gap will widen to 2 degrees. Look below the planet and star for Mars and Mercury. Mercury will be the brighter of two, shining at magnitude -.19. While making its 88 Earth-day journey around the Sun, Mercury travels at an average of 30 miles per second. As Mercury completes one rotation every 59 days, and at an average distance from the Sun of only 36 million miles, its surface experiences extreme temperatures, ranging from -300 degrees to 900 degrees Fahrenheit.

During these last days of summer, the Big Dipper can be seen low, and parallel to the northern horizon, before it begins its circumpolar rise up along the eastern side of Polaris. During the autumn months, the Big Dipper will begin the night to the east of Polaris. Cassiopeia takes the opposite trek, always on the other side of Ursa Major and its Big Dipper asterism.

The second brightest comet in our sky is C/2017 O1 (ASASSN). Detected by the All Sky Automated Survey for Supernovae (ASAS-SN) system on July 19, 2017, this comet is currently 9thmagnitude, and will brighten to its maximum of 8th magnitude in October. The comet is between the Pleiades star cluster and Aldebaran in Taurus. Take advantage of the dark skies created by the New Moon to find this comet about 6 degrees to the lower left of the Pleiades. Use binoculars or a small telescope.

The Albany Area Amateur Astronomers welcome you to join them for their monthly meeting to be held Thursday, beginning at 7:30 p.m. at miSci in Schenectady. Members will be sharing their photos, and experiences of the August 21st solar eclipse.

Skywatch Line for Monday and Tuesday, September 18th and 19th, 2017

This is the Skywatch Line for Monday and Tuesday, September 18th and 19th.

The Sun sets at 7 PM; night falls at 8:35. Dawn begins at 5:04 AM and ends with sunrise at 6:39.

Jupiter and Saturn are evening planets. Jupiter is hanging on, just 6 degrees above the western horizon – too low for useful observations. Shining at minus 1.7 magnitude, its best observed with binoculars before its sets at 8:09 PM.

Zero magnitude Saturn, in Ophiuchus, is moderately low in the southern sky. Last week, it reached Quadrature, which means that the Sun lights it from the side. Moderately sized telescopes should show the planet’s shadow on the ring system. Saturn sets at 11:02 PM.

Nightfall presents Neptune and Uranus. Neptune rises during Civil Dusk. The 7th magnitude planet inhabits Aquarius, near the bright star Hydor, is best observed at about Midnight, and sets at 5:32 AM. Uranus, in Pisces, shines with 5th magnitude, is slightly larger than Neptune and rises at 8 PM. Located near the star Omega Piscium, it is best observed at 2:45 AM. Both require detailed charts from astronomical media.

The constellation Perseus is well up by Midnight. The star Algol, on Perseus’ shorter leg, dims at 4:28 AM on Wednesday. Begin observing it about two hours before that time to fully witness the occultation.

Three planets and the Moon rise in Leo during Dawn. Brilliant Venus is the first, rising at 4:17 AM. The planet blazes at minus 4th magnitude, is 11.6 arc-seconds in size, appears about 88 percent illuminated and lies about 1 degree from the 1st magnitude star Regulus. Mars rises next at 5:07 AM, about 9 degrees below Venus. The Red Planet shines at 1st magnitude and is 3.6 arc-seconds in size. Two degrees below Mars, minus 1st magnitude Mercury is next at 5:18 AM, 6 arc-seconds in size and appears about 75 percent lit. Tuesday’s Moon is last, rising at 5:28 AM, about 3 degrees high and about 1 percent lit. Tuesday’s Moon is a challenge object, with the lunar crescent being so thin and low in the brightening sky. Wednesday’s Moon is not visible; it turned officially New at 1:30 AM.

Note that this alignment forms a straight line from the Eastern horizon to Venus. Tuesday’s Dawn provides a visual demonstration of the Ecliptic – the path of the Sun, Moon and planets across our sky. Binoculars may be necessary to see them amid the rising Sun’s glare.

There are some objects that are perfect binocular targets. Directly overhead, the constellation Cygnus seems to fly south for the winter. Below the Swan’s nose is a small constellation – Sagitta. The Latin name means “arrow”, and that is exactly what it looks like.

Just above the “Arrow’s” tail feathers is a curious object. The Coathanger is an asterism – a starry image, but not a constellation. This is a perfect binocular target, since a telescope’s magnification destroys the illusion. The Coathanger also goes by the names: Collinder 399 and Brocchi’s Cluster. However, the Coathanger is not a true cluster. Hipparchos satellite measurements show that it is a random placement of stars that just happen to resemble an everyday article.

Skywatch Line for Friday, September 15 through Sunday, September 17, 2017

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

On Friday, Sun rises at 6:36am and sets at 7:05pm; the Waning Crescent Moon sets at 4:22pm and rises at 1:22am.

On Saturday morning, approximately 70 minutes before sunrise, enjoy the view of Mercury and Mars sitting only 0.3 degree apart. Mercury, at magnitude –0.8, outshines 1.8-magnitude Mars. It’s rare for two planets to pass so near to each other. Look eastward in the direction of sunrise. You can’t miss the waning crescent Moon and Venus in the predawn sky. The Moon and Venus help guide you to Mercury and Mars. Use binoculars or a small telescope to spot the two close planets.

This is the time of year to enjoy the Andromeda Galaxy, M31. If your skies are dark and clear, you can spot M31 without optical aid. Andromeda is located at the end of a string of moderately bright stars consisting of Beta (β), Mu (μ) and Nu (ν) Andromedae. A telescope lets you glimpse M31’s small satellites M32 and M110. It will also help reveal one or two of the main galaxy’s dust lanes. The Andromeda galaxy lies some 2.5 million light-years away. It is the nearest major spiral system to the Milky Way. Andromeda and the Milky Way are on a slow-motion collision course. Recent studies indicate that these two giants will collide and merge into a single, super-massive galaxy. Luckily, It won’t happen for another four billion years!

Beginning this Saturday morning, you might have a chance to spot the zodiacal light. It is a large, cone-shaped glow that seems to angle up from the eastern horizon before the start of twilight. You’ll need a dark sky to observe it. If the Milky Way isn’t visible from your location, you won’t be able to see the zodiacal light.

Spot Uranus unaided this week. Uranus of magnitude 5.7 is in Constellation Pisces and is well up in the east by late evening. Scientists forecast rainstorms of solid diamonds on Uranus and Neptune. In a recent study researchers say they were able to produce this “diamond-rain” in the lab for the first time. It was always thought that the extreme high pressure on Uranus and Neptune would squeeze the carbon atoms in the atmosphere allowing diamond rain to fall.

Sunday marks the anniversary of the International Cometary Explorer (ICE) mission. On September 17, 1985, the International Cometary Explorer flew relatively unscathed through the gas tail of comet P/Giacobini-Zinner, at a speed of 21 km/sec at its closed approach of some 7,800-km downstream from the nucleus. The spacecraft found a region of interacting cometary and solar wind ions, and encountered a comet plasma tail about 25,000 km wide. Water and carbon monoxide ions were also identified, which confirmed the “dirty snowball” theory proposed by Fred Whipple in 1950.

Skywatch Line for Wednesday, September 13th, and Thursday, September 14th, 2017

This is the Dudley Observatory Skywatch Line for Wednesday, September 13th, and Thursday, September 14th, written by Louis Suarato.

The Last Quarter Moon occurs at 2:26 a.m. Wednesday. The Moon will reach perigee, its closest distance to Earth during this lunar cycle, at 12:06 p.m., also on Wednesday, at a distance of 229,820 miles. The average distance of the Moon to Earth is 238,855 miles, or about 30 Earth diameters. The furthest distance the Moon travels from Earth is 252,088 miles, or about 32 Earth diameters. At its closest, the Moon is 225,623 miles away, or between 28 and 29 Earth diameters. The Moon will set at 2:27 p.m., and rises again at 22 minutes past midnight as a 40% illuminated, waning crescent. Jupiter is only 10 degrees above the west-southwestern horizon at civil twilight. Look for Saturn about 25 degrees above the south-southwestern horizon as the sky darkens. Saturn sets at 11:13 p.m. in the southwest. Saturn reaches its eastern quadrature on Thursday. That is when a planet is perpendicular to the Sun, and receiving its light at a right angle. This angle creates long shadows and gives the ringed planet a 3 dimensional appearance through telescopes. This is equivalent to the Moon during the First and Third Quarter phases. Saturn’s rings are tilted at an angle of 26 degrees toward Earth, the most in 15 years. When the Moon rises overnight, you will notice its location between the constellations Gemini and Orion. The Moon is also in the middle of the asterism known as the Winter hexagon. The stars that comprise this asterism are; (clockwise from the Moon’s left) Pollux in Gemini, Capella in Auriga, Aldebaran in Taurus, Rigel in Orion, Sirius in Canis Major, and Procyon in Canis Minor. Look 25 degrees to the left of Procyon, and 16 degrees above Venus for M44, the Beehive Cluster, in Cancer. Binoculars will reveal the Moon is in the foreground of four open star clusters. Look for M35, and NGC 2129 above the Moon, NGC 2175 between M35 and the Moon, and NGC 2169 to the Moon’s right. Venus rises in Leo at 4:08 a.m., followed by Mercury at 5:02 a.m., and Mars, 8 minutes later. This is Mercury’s best morning appearance of the year as it is a day past its greatest western elongation, about 18 degrees from the Sun.

Skywatch Line for Monday and Tuesday, September 11th and 12th, 2017

This is the Skywatch Line for Monday and Tuesday, September 11th and 12th.

The Sun sets at 7:12 PM; night falls at 8:49. Dawn begins at 4:55 AM and ends with the Sun rising at 6:32.

Two bright planets inhabit the evening sky. Jupiter, in Virgo, is hanging on. It is low in the West about 9 degrees high, and 3 degrees above the bright star Spica. Jupiter sets at 8:37 PM. Binoculars may be needed to find it amid the sunset’s glare.

Saturn is moderately high in the southern constellation of Ophiuchus. At zero magnitude, it is about 24 degrees high and about 13 degrees to Antares’ upper left. Saturn is still worthy of observation for its glorious rings; it is also still 3 degrees below the binocular globular star cluster M-9. Saturn sets at 11:28 PM.

Nightfall reveals two outer planets. Neptune is well up in Aquarius and shines at 8th magnitude 19 degrees above the southwestern horizon, near the star Hydor. Neptune is best seen around 12:30 AM. Uranus is also up and in Pisces. Brighter at 5th magnitude and slightly larger, it is located near the star Omicron Piscium. Uranus is best observed at 3:14 AM. Detailed charts from astronomy media are helpful.

The Moon rises in Taurus before Midnight on both nights. Monday, the minus 10th magnitude waning crescent appears about 62 percent illuminated and is best observed at 6 AM. Tuesday finds the Moon also as bright, but only 50 percent lit; it becomes officially Last Quarter at 2:25 AM, Wednesday. During Tuesday’s pre-dawn, the Moon seems to devour, several Hyades stars. Then, it occults (eclipses) the bright star Aldebaran during daytime.

Venus rises in Leo at 4 AM, shining at minus 4th magnitude, appearing about 86 percent illuminated and 9 degrees high.

Mars rises also in Leo at 5:11 AM, shines at minus 2nd magnitude and is 9 degrees high at Civil Dawn. Mercury, which is now at its greatest distance from the Sun, joins Mars by shining at minus 0.3 magnitude and appearing about 46 percent illuminated. Mars and Mercury are separated by 3 degrees and the duo is 11 degrees below bright Venus. Binoculars are suggested for the observer, due to the Dawn’s glare.

The past two weeks witnessed hurricanes devastating American cities. As bad as these cyclones were, they are small compared to storms on other solar system members. The most famous example is the Great Red Spot on Jupiter. This tempest has been continuously observed for three hundred years, and is probably older. The Great Red Spot is actually a high-pressure hurricane, larger than the Earth. Recently, astronomers discovered that the Great Red Spot is gradually shrinking; the cause is unknown. Jupiter experiences ordinary thunderstorms that radio amateurs can pick up on ham radios. Saturn periodically displays cyclones. In 2010, amateur astronomers discovered the Great White Spot, a thunderstorm over 100 times larger than earthly ones. Uranus displayed an outburst, with 500 miles-per-hour winds, that lasted five years. Neptune periodically displays severe weather; the Hubble Telescope saw a storm in 2015 and again in 2016. Finally, our Sun is constantly flaring and expelling clouds of charged particles. Corporations and governments retain solar scientists to predict Space Weather, so that satellites, communications and astronauts are protected.

Skywatch Line for Friday, September 8 through Sunday, September 10, 2017

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

On Friday, Sun rises at 6:28am and sets at 7:18pm; the Waning Gibbous Moon sets at 8:49am and rises at 8:52pm. Full Moon occurred on Thursday at 3:03am.

The Waning Gibbous Moon and Uranus both reside in front of the constellation Pisces, the Fishes, on Friday night. Rising over the eastern horizon by around mid-evening, Uranus will remain within Pisces’ borders for the rest of the year. However, the Moon will leave Pisces after a day or two. With the Moon bright and so close to Uranus on the sky’s dome, you will need binoculars or a telescope to be able to spot Uranus. People with good vision can see Uranus with the unaided eye on dark, moonless nights. Uranus was the first planet to be discovered by the telescope, by William Hershel on March 13, 1781. At a distance of about 19 astronomical units from Earth at present, Uranus is easy to see through binoculars if you know exactly where to look. First locate the constellation Pisces after the Moon leaves the evening sky. If you’re familiar with the Great Square of Pegasus, jump off from there to the constellation Pisces the Fishes. With a sky chart and binoculars you would be able to catch Uranus, the seventh planet from the Sun.

On Sunday morning, look for planet Mercury and the star Regulus, in constellation Leo, the lion, to couple up together before sunrise. This upcoming week is a great time for catching Mercury in the morning sky. Mercury, the innermost planet of the solar system, will reach its greatest morning elongation from the Sun of 18 degrees west on Tuesday. Get up 90 or 75 minutes before the Sun and find an unobstructed horizon in the direction of sunrise. Look eastward for the shining planet Venus and then search for Mercury below Venus. In a clear sky, you may spot Mercury near the sunrise point on the horizon with the eye alone around 80 to 70 minutes before sunrise. You might need binoculars to see Mercury in the morning twilight less than one hour before sunrise. Use binoculars to view Mercury and Regulus in the same binocular field. Mercury is shining 3 to 4 times brighter than Regulus. Mercury will brighten day by day. In the next days, the gap between Mercury and Regulus will increase, as Regulus climbs toward Venus in the morning sky.

On Sunday night, wake up before dawn to see the Moon and the constellation Taurus higher up in the predawn sky. Look for the Moon then seek out Taurus’ two prominent signposts, the star Aldebaran and the Pleiades star cluster. Right now, the Moon is moving toward Aldebaran on the sky’s dome. In a couple of days, Aldebaran will disappear behind the Moon’s illuminated side and then reappear on the Moon’s dark side. The Lunar occultation of Aldebaran will take place on Tuesday.

Sunday marks the birthday of the American astronomer James E Keeler. Born on September 10 1857, James Edward Keeler was the American astronomer who confirmed Maxwell’s theory that the rings of Saturn were not solid but composed of meteoric particles with rotational velocity given by Kepler’s 3rd law. James’ spectrogram of the rings of Saturn showed the Doppler shift indicating variation of radial velocity along the slit. At the age of 21, he observed the solar eclipse of July 1878, with the Naval Observatory expedition to Colorado. He directed the Allegheny Observatory and the Lick Observatory, where he observed large numbers of nebulae whose existence had never before been suspected.

Skywatch Line for Wednesday, September 6th, and Thursday, September 7th, 2017

This is the Dudley Observatory Skywatch Line for Wednesday, September 6th, and Thursday, September 7th, written by Louis Suarato.

The Full Moon occurs at 3:04 a.m. Wednesday. Use binoculars, or a small telescope to find Neptune, one day past opposition, 1 degree to the right of the Moon. If you are up early watching the Full Moon setting Wednesday morning, look to its right at 5:18 a.m. to see the International Space Station emerge from darkness and sail northeastward. The ISS will cross Pegasus before heading toward the Little and Big Dippers. The Moon will set at 6:35 a.m., and rise again at 7:48 p.m. as a 99% illuminated, waning gibbous Moon. As the Moon is setting in the constellation Aquarius, Venus is rising in Cancer. Look 6 degrees above Venus for M44, the Beehive Cluster. Mercury and Mars, 2 degrees from each other, rise in Leo 8 minutes apart. Mercury rises first at 5:10 a.m., followed by Mars to its lower left. Jupiter remains in the sky until an hour and a half past sunset, and sets at 8:47 p.m. in Virgo. Saturn continues to provide the best view of the night, as it shines high above the southern horizon after sunset.

The Cassini spacecraft is in its final days as it soars in and out of Saturn’s rings before it sails into the ringed planet’s atmosphere on September 15th. On September 9th, Cassini will make its last dive between the planet and rings, flying 1,044 miles over Saturn’s cloud tops. On September 11th, Cassini will fly 73,974 miles over Titan, Saturn’s largest moon. The spacecraft’s final images will be taken and downloaded on September 14th, and on September 15th Cassini plunges into Saturn’s atmosphere. The entire mission will have lasted 19 years and 11 months.

Skywatch Line for Monday, Labor Day, and Tuesday, September 4th and 5th, 2017

This is the Skywatch Line for Monday, Labor Day, and Tuesday, September 4th and 5th.

The Sun sets at 7:24 PM; night falls at 9:03. Dawn begins at 4:45 AM and ends with sunrise at 6:24.

The Moon and two planets are visible in the darkening sky. Monday’s Moon is almost “full” in Aquarius, blazes at minus 12th magnitude and appears about 98 percent illuminated. The Moon is officially “Full” at 3 AM, Wednesday.

Jupiter shines at minus 1.7 magnitude in Virgo, about 3 degrees above the bright star Spica and 11 degrees above the western horizon; Tuesday is Jupiter’s second conjunction of the year with Spica. Now is the time for last looks before it disappears into the setting Sun’s glare. Jupiter sets at 8:57 PM.

Zero magnitude Saturn is about 24 degrees high in the southern constellation Ophiuchus. Its beautiful rings are fully tilted for our enjoyment. Saturn lies about 13 degrees to the upper left of the red star Antares and about 3 degrees below 7th magnitude globular cluster M-9, visible in binoculars and telescopes. Saturn sets before Midnight.

Nightfall presents distant Neptune in Aquarius. Neptune shines at 8th magnitude and reaches Opposition on Tuesday, which means that it rises at sunset and sets at sunrise. Opposition usually means that it is the best time to observe a planet; however, the almost Full Moon shares Aquarius on Monday night, and sits next to Neptune on Tuesday night, virtually blotting it out.

Uranus rises in Pisces at 8:57 PM, appears about 5th magnitude and a tiny 3.7 arc-seconds in size. This blue-green dot is best observed at about 3:42 AM and is about 32 degrees high. Detailed finder charts help in locating it.

Minus 4th magnitude Venus rises at 3:44 AM in Cancer, appearing about 85 percent lit and about 10 degrees high in the East. Pre-dawn observers can spot the Beehive star cluster 5 degrees above the clouded planet.

The brightening Dawn sky contains not only Venus, but Mars and Mercury in Leo. Venus glows about 15 degrees above the Mars-Mercury duo. Mars rises about 5:16 AM, is about 7 degrees above the eastern horizon and is a tiny 3.6 arc-seconds in size. Mercury rises after Mars, is brighter at 1st magnitude, larger at 8.9 arc-seconds and is 17 percent illuminated. Mars lies near Leo’s brightest star, Regulus. These three low objects are best observed through binoculars.

Saturn guides to globular cluster M-9. Globular clusters are dense, highly symmetrical gatherings of some of the oldest stars in the galaxy. They may contain a million stars and are found mostly in the vast halo that surrounds our Milky Way Galaxy. Globulars are concentrated toward the galaxy’s center. The stars are old, about 13 billion years, and generally poor in elements more complex than Hydrogen and Helium. While astronomers have counted 146 in our galaxy, the neighboring Andromeda Galaxy possesses about 400.

M-9 was discovered by French comet hunter Charles Messier in May 1764. He called it a “faint nebula without stars.” In 1784, Sir William Herschel, using his giant telescope, resolved it into a star cluster. M-9 is the smallest cluster in Ophiuchus. It’s about 7500 light-years from the galactic center and about 26,000 light-years from our Solar System. Its diameter measures about 60 light years.

Skywatch Line for Friday, September 1 through Sunday, September 3, 2017

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

On Friday, Sun rises at 6:13am and sets at 7:42pm; the Waxing Gibbous Moon sets at 10:00pm. First quarter Moon occurs on Tuesday at 4:13am.

Jupiter, at magnitude –1.7, sits very low in the southwest at dusk and sets as twilight ends. That leaves Saturn, at magnitude 0.4, as the sole evening planet. Saturn is already past the meridian at sunset. As darkness falls, the ringed planet is roughly 20 degrees above the south-southwest horizon. The rings are now tilted open almost the maximum amount, you should be able to detect the famous Cassini Division, a 4,700-kilometre-wide gap that separates Saturn’s two brightest ring components. When the atmosphere is steady, this dark, threadlike feature is visible even in a 60mm refractor. Try to spot Saturn’s moons as well. Titan shines at magnitude 8.4, and is usually the brightest point of light near the planet.

Orion, the Hunter is always behind the Sun as seen from Earth in June. It comes back to the predawn sky every year in late July. By early September, Orion is rising in the wee hours and is well up in the southeast an hour before dawn. Orion will soon be up by midnight. By December you’ll find it rising in early evening. Orion’s Belt points to Sirius in the constellation Canis Major, the Greater Dog, the brightest star of the nighttime sky. Orion’s Belt consists of a short, straight row of medium-bright stars. Just draw a line through Orion’s Belt and extend that line toward the horizon. You’ll easily spot Sirius, the sky’s brightest star. It’s often called the Dog Star.

Sunday marks the anniversary of Viking II landing on Mars. On September 3, 1976, the unmanned spacecraft Viking II landed on Mars and took the first pictures of the surface of Mars. Its twin, Viking I was the first to arrive on the surface of Mars on 20 Jul 1976. Each lander housed instruments that examined the physical and magnetic properties of the soil, analyzed the atmosphere and weather patterns of Mars, and determined any evidence of past or present life. Each Viking spacecraft was made of two parts: an orbiter and a lander. The orbiter’s initial job was to survey the planet for a suitable landing site. Later the orbiter’s instruments studied the planet and its atmosphere, while the orbiter acted as a radio relay station for transmitting lander data.