Skywatch Line for Friday, October 18, through Sunday, October 20, 2019

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

On Friday, Sun rises at 7:12am and sets at 6:09pm; the waning gibbous Moon rises at 9:18pm and sets at 11:48am.

Saturn, at magnitude 0.5, resides among the background stars of constellation Sagittarius the Archer, 25 degrees high in the south-southwest as twilight fades to darkness. It appears significantly brighter than any of its host constellation’s stars. Even a small telescope shows Saturn’s disk and spectacular ring system, which spans 37 arc-seconds and tilts 25 degrees to our line of sight. Saturn sets around 11pm.

Mercury reaches greatest elongation at midnight on Saturday. At that time, Mercury stands 25 degrees east of the Sun. Mercury climbs just 3 degrees high 30 minutes after sunset. Mercury and Venus are very low in bright twilight after sunset. Start by trying for Venus, at magnitude –3.9, just above the west-southwest horizon a mere 20 minutes after sunset. Some 8 degrees to its left is Mercury, much dimmer at magnitude –0.1. That’s only 3 % as bright as Venus. Use binoculars to help you locate Mercury.

Jupiter, at magnitude –2.0, is the white dot low in the southwest in the feet of Constellation Ophiuchus, as twilight fades. Jupiter is nearly on the far side of the Sun from us, appearing only 35 arc-seconds wide in a telescope and very smush in the low-altitude seeing.

Vega, in constellation Lyra, is the brightest star high in the west after dark. To its lower right by nearly a fist and a half at arm’s length, look 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. The main stars of Vega’s own constellation, Lyra, now extend to Vega’s left. They are quite faint by comparison. Altair, in constellation Aquila, is about equally high as Vega but not quite as bright. Just upper right of Altair, by a finger-width at arm’s length, spot little orange Tarazed. Down from Tarazed runs the stick-figure backbone of Aquila, the Eagle. If you have a dark sky, make your acquaintance with the constellation Draco. Draco is a circumpolar constellation. It is out all night long every night of the year. This serpentine star figure wanders in between the Big and Little Dippers, with its tail found between the bowl of the Big Dipper and the star Polaris.

Friday marks the 30th. anniversary of Galileo space orbiter launch. The craft gained speed from gravity assists in encounters with Venus and Earth before heading outward to Jupiter. During its six year journey to Jupiter, Galileo’s instruments made interplanetary studies, using its dust detector, magnetometer, and various plasma and particles detectors. It also made close-up studies of two asteroids, Gaspra and Ida in the asteroid belt. The Galileo orbiter’s primary mission was to study Jupiter, its satellites, and its magnetosphere for two years.

Skywatch Line for Wednesday, October 16th, and Thursday, October 17th, 2019

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

The 93% illuminated, waning gibbous Moon rises at 7:58 p.m. Wednesday. The Moon rises between the horns of Taurus, the bull, with its red eye, Aldebaran, below, and the Pleiades above. Aldebaran is a red giant star about 65 light years from the Sun. It is the brightest star in the constellation Taurus, and the 14th brightest in our sky. Aldebaran shines between magnitude 0.75 and 0.95. Thursday night, Aldebaran will be 3 degrees to the Moon’s right. The Sun sets at 6:10 p.m., followed by Venus at 6:54 p.m., and Mercury at 6:58 p.m.. Jupiter sets in the west-southwest at 9:05 p.m., leading Saturn by an hour and 46 minutes. Mars rises at 5:52 a.m., Thursday, an hour and 18 minutes before sunrise.

With the bright Moon blanching celestial objects in its path across the sky, if you are observing during these nights, you may want to concrete on the brightest targets. The Andromeda Galaxy, M31, is close to the zenith, or directly overhead, around midnight. M31 shines at magnitude 3.44. The constellation Cygnus is high above the southwestern horizon around 9 p.m.. One of the features within this constellation is the double star Albireo, comprised of one gold star and one blue star. The Swan faces downward these nights, with Albireo, at the head, leading the way. M13 is one of the most spectacular globular clusters in the sky. Shining at magnitude 5.80, this cluster of over three hundred thousand stars, can be found in the constellation Hercules, along one of the sides making up its Keystone asterism. You’ll find M13 in Hercules 33 degrees above the west-northwestern around 9 p.m..

The Albany Area Amateur Astronomers invite you to join them for their monthly meeting to be held Thursday beginning at 7:30 p.m. at miSci in Schenectady. This month’s speaker will be Dr. Luca Marinelli, who will give a presentation on the “Introduction to Deep-Space Astrophotography”. Dr. Marinelli is a Principal Scientist at GE Global Research, where his work has focused on neuroimaging and advanced technologies for quantitative MRI since 2005. Dr. Marinelli graduated from Università degli Studi di Genova with a degree in physics in 1995 and earned his Ph.D. in Physics at Harvard University in 2002. He studied low-temperature thermodynamic and transport properties of high-temperature superconductors in a strong magnetic field. He also collaborated with Schlumberger-Doll Research to develop a magnetic resonance tool for exploration of geological reservoirs. After leaving Harvard, Dr. Marinelli joined Bell Laboratories-Lucent Technologies as a postdoctoral member of the technical staff in the theoretical physics group, where he worked on problems in information theory and wireless telecommunications. Dr. Marinelli holds 30 patents and is a coauthor on over 100 journal publications, book chapters, and conference proceedings.

Skywatch Line for Monday and Tuesday, October 14th and 15th, 2019

This is the Skywatch Line for Monday and Tuesday, October 14th and 15th, written by Joe Slomka.

The Sun sets at 6:15 PM; night falls at 7:49. Dawn begins at 5:34 AM and ends with the Sun rising at 7:08.

Jupiter and Saturn are no longer the only planets visible in the evening sky. Mercury and Venus, both in Virgo, rise shortly before Sunset, can be found low in the Southwest, separated by about 8. Venus is brightest, blazing with minus 4th magnitude and appearing about 96% illuminated, 6degrees above the horizon. Mars is a bit dimmer and about 71% lit and appears a bit higher than Venus. Both require binoculars to find them amid the setting Sun’s glare. Both set by 7 PM. Astronomy magazines and websites provide finder charts to aid observers.

Jupiter still occupies Ophiuchus, glowing with minus 2nd magnitude and appearing about 21 above the southwestern horizon. It sets at 9:12 PM.

Saturn also remains in Sagittarius, shining with zero magnitude. It trails Jupiter by about 2 hours and appears moderately low in the South. The Ringed Planet is best observed at 6:25 PM and sets about 11 PM. Saturn appeared in the news last week. The Minor Planet Center announced that Jupiter is no longer king of the planets. Astronomer Scott Shepard discovered 20 new moons for Saturn for a total of 82 satellites; Jupiter held the record at 79. Shepard first photographed them in 2004 and 2005, but spent years determining their orbits and predicting their position, so that other astronomers could verify the discovery. Most of the new moons are about 5 kilometers wide (3 miles); 17 of them orbit backwards in respect to Saturn and the other satellites.

Late evening reveals Neptune, still in Aquarius, near the star Phi Aquarii. It shines with 8th magnitude and appears a tiny 2 arc-seconds in size. It is best observed at 10:33 PM and sets at 4:12 AM. Uranus holds court in Aries, shines with 5th magnitude, appears a bit larger than Neptune, and is about 53 high. It is best viewed at 1:33 AM and remains up all night. Again, astronomy magazines and websites provide finder charts.

The 16-day-old Monday’s Moon rises in Cetus at 7:03 PM, appearing about 98% lit and blazing with minus 12th magnitude. Tuesday, the Moon migrates to Aries and appear slightly thinner and dimmer; it rises at 7:30 PM. On both days, the Moon remains up past Sunrise.

Mars makes his reappearance in our Dawn sky. In Virgo, it rises at 5:53 AM, appearing about 99% lit, glowing with first magnitude and appearing about 8 above the eastern horizon. Again, binoculars are suggested.

Besides Saturn, the Nobel Prize in Physics also made headlines. Three astronomers will be honored. James Peebles won the prize for his work on the Cosmic Microwave Background (CMB). In 1929, American astronomer Edwin Hubble discovered that galaxies were flying away from each other. Belgian Catholic Priest-astronomer George Lemaitre, using Einstein’s theories, proposed a sudden creation and expansion of the universe in 1939, now known as the Big Bang. James Peebles studied the Big Bang and realized that it would leave a trace of cosmic radiation. Bell Labs engineers Wilson and Penzias, while trying to understand static in radio transmissions, realized that the static was the CMB leftovers of the Big Bang. They were rewarded with the Nobel Prize in 1978. Now, the Nobel Prize was awarded to Peebles for his research.

In addition, Michel Mayor and Didier Queloz shared the Nobel Prize with Peebles for their discovery of the first exoplanet orbiting a sun-like star, 51 Pegasi b. To date, over 4000 exoplanets have been discovered, with about an equal number awaiting confirmation.

Skywatch Line for Friday, October 11, through Sunday, October 13, 2019

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

On Friday, Sun rises at 7:04am and sets at 6:20pm; the waxing gibbous Moon rises at 5:52pm and sets at 4:37am. Full Moon occurs on Sunday at 5:08pm. October’s Full Moon is the “Hunter’s Moon”. In early autumn, the Full Moon rises about half an hour later each night compared with a normal lag close to fifty minutes. The added early evening illumination helps hunters track down their prey.

Look above the nearly full Moon, on Saturday evening, for the Great Square of Pegasus through the moonlight. The Square is balancing on one corner. Your fist at arm’s length fits inside it. Watch when the Square’s top corner is exactly above its bottom corner. This will probably by sometime soon after the end of twilight.

Soon after dark, you’ll find zero-magnitude Arcturus, the brightest star in the constellation Boötes, low in the west-northwest at the same height as zero-magnitude Capella, the brightest star in the constellation Auriga, in the northeast. Turn to the south-southeast, and there will be 1st-magnitude Fomalhaut at the same height. In the southwest at that time you’ll find bright Jupiter about as high as Fomalhaut. Jupiter continues to dominate the early evening sky in southern constellation Ophiuchus, the Serpent-bearer. The giant planet shines at magnitude –2.0 and stands some 15 degrees above the southwestern horizon as twilight fades to darkness. When viewed through a telescope, you also should see the four Galilean moons, Io, Europa, Ganymede, and Callisto, as bright points of light arrayed around the planet.

Although autumn began and the stars of winter’s Orion now rule the morning sky, the Summer Triangle remains prominent on early October evenings. The constellation Orion the Hunter appears on its side as it rises, with ruddy Betelgeuse to the left of the three-star belt and blue-white Rigel to the belt’s right. As Orion climbs higher before dawn, the constellation rotates and Betelgeuse lies at the upper left and Rigel at the lower right of the constellation pattern. Look high in the west after darkness falls for brilliant star Vega in the constellation Lyra the Harp. Vega, at magnitude 0.0, is the brightest member of the Summer Triangle. The second-brightest star, magnitude 0.8 Altair in constellation Aquila the Eagle, lies some 35 degrees southeast of Vega. The triangle’s dimmest member, magnitude 1.3 Deneb in constellation Cygnus the Swan, stands about 25 degrees east-northeast of Vega. Deneb passes through the zenith about an hour after the last traces of twilight disappear.

Try watching for Earth’s shadow in both the evening and morning sky,. It is the blue-grey darkness in the direction opposite the Sun, darker than the twilight sky. Earth’s shadow can be seen ascending in the eastern sky at the same rate that the Sun sets below the western horizon. The shadow is curved, just as the shadow of any round object is curved. Earth’s shadow is best seen when the horizon is low, such as over the sea, and when the sky conditions are clear. In addition, the higher the observer’s elevation is to view the horizon, the sharper the shadow appears. The pink band above the shadow in the east after sunset, or west before dawn, is called the Belt of Venus. The arch’s light pink color is due to the backscatter of reddened light from the rising or setting Sun. A very similar effect can be seen during a total lunar eclipse. The zodiacal light, which is caused by the diffuse reflection of sunlight from the interplanetary dust in the Solar System, is also a similar phenomenon.

Skywatch Line for Wednesday, October 9th, and Thursday, October 10th, 2019

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

The 86% illuminated, waxing gibbous Moon rises at 5 p.m. Wednesday. Look 17 degrees below the Moon for Fomalhaut, the Autumn Star. The Moon will reach apogee, its furthest distance from Earth during this lunar cycle, at 2:29 p.m. Thursday, at the distance of 252,214 miles. The Moon’s orbit around Earth is elliptical. An elliptical orbit is defined as an orbit with an eccentricity of less than, or greater than 0. An eccentricity of 0 would be a perfectly circular orbit. The Moon’s elliptical orbit ranges from a distance of 221,500 miles to Earth to 252,700 miles. , an average of 239,228 miles.

Venus leads Mercury into the west-southwestern horizon, setting at 7 p.m., about a half hour after sunset. Jupiter is next, setting at 9:28 p.m., followed by Saturn, which will set at 11:17 p.m.. After Venus and Mercury have set, the International Space Station will rise out of the west-northwest horizon. This -2.9 magnitude pass will appear at 7:10 p.m., and pass Arcturus at 7:12. The ISS will continue south, passing the Summer Beehive Cluster in Ophiuchus at 7:14. The Space Station continues over Jupiter and Saturn, and past the Wild Duck Cluster in Scutum. The ISS completes its pass through Capricornus before it sails below the Moon before heading into the southeastern horizon.

Mars is making a comeback to the pre-dawn sky, rising at 5:56 a.m., about an hour before sunrise. Mars is currently 99.5% illuminated. Like Earth, Mars also has four seasons, but because Mars’ eccentricity is greater than Earth’s and its axial tilt is different, its seasons are different lengths. In the Martian northern hemisphere, spring is 7 months, summer lasts 6months, fall is 5.3 months, and winter is just over 4 months. Mars’ summer solstice occurred on October 8th this year.

Skywatch Line for Monday and Tuesday, October 7th and 8th, 2019

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

The Sun sets at 6:26 PM; night falls at 8. Dawn breaks at 5:26 AM and ends with the Sun rising at 7.

The Moon dominates the evening sky, in Capricornus on both nights. On Monday, the 9-day-old Moon is already up and blazing with minus 10th magnitude and appearing about 70% illuminated. It is best observed at 8:44 PM, when it is about 21 high; it sets at 1:17 AM, Tuesday. Tuesday evening sees it about 80% lit and a bit brighter. It is best observed at 9:30 PM and sets Wednesday at 2:27 AM.

Jupiter and Saturn continue to be the only easily visible evening planets. Jupiter, still in Ophiuchus, glows with minus 2nd magnitude, appears about 35 arc-seconds in size and is about 19 high. It sets at 9:35 PM.

Saturn rises about 2 hours after Jupiter. It still resides in Sagittarius. The Ringed Planet shines with zero magnitude and appears half Jupiter’s size. It lies quite low, about 24 above the horizon, but still presents a nice view of its famous rings. It sets at 11:24 PM.

Both Mercury and Venus have completed superior conjunction with the Sun and are now visible. Both are very low on the western horizon and share Virgo. Mercury appears about 80% lit, glows with minus zero magnitude, is 2 high and sets at 7:08 PM. Venus lies about 8 to Mercury’s lower right. It appears nearly “full” and blazes with minus 4th magnitude. However, it is only about 1 high and sets about 34 minutes after sunset. Binoculars are recommended in seeking these elusive planets. Observers are cautioned to steer clear of the Sun.

Neptune is already up in Aquarius. It is nearly 8th magnitude and is a tiny 2 arc-seconds in size, but 25 high in the southeast. It is best observed at 11:08 PM and sets at 4:04 AM. Uranus rises in Aries at 7:11 PM, appearing brighter and a bit larger than Neptune. It is highest at 1:58 AM and sets after sunrise. Finder charts are available from astronomy magazines and websites.

Mars makes a fleeting appearance just before sunrise, rising at 5:57 AM. By Civil Dawn, it shines with 1st magnitude, is a tiny 3 arc-seconds in size and is almost 6 above the eastern horizon. We mention this now, because a year from now it will be 6 times wider and at Opposition, the best time to see Mars. Also, on Monday, Mars experiences its Summer Solstice. Since Mars takes 2 earth-years to circle the Sun, its seasons last 6 months.

Monday marks the 27th anniversary of a car accident; but the cause of this fender-bender was unusual. On October 9, 1992, a fireball (very bright meteor) streaked through the sky. Sixteen different cameras that were recording local high school football games videotaped it. It was the first meteor to be captured in flight. The meteorite crashed into Michelle Knapp’s Chevy Malibu, in Peekskill, New York, totaling it. Although the annual minor Draconid meteor shower was taking place, the origin of the meteor is still uncertain. The multiple recording of its path provided meteor scientists with a rare opportunity to actually determine the meteorite’s origin. Ms. Knapp sold both the meteorite and damaged car to collectors. The 4.4-billion-year-old football-sized rock weighted 26 pounds. It was part of a broken-up asteroid. The stony meteorite is about twenty percent nickel-iron. Specimens of the Peekskill Meteorite can be seen in the American Museum of Natural History in New York City, the Smithsonian and Chicago’s Field Museum.

The Draconid meteor shower is now at its peak. The Orionid Meteor Shower, a product of Halley’s Comet, will also have its peak on the night of October 21/22.

Skywatch Line for Friday, October 4, through Sunday, October 6, 2019

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

On Friday, Sun rises at 6:56am and sets at 6:32pm; the waxing crescent Moon rises at 1:33pm and sets at 10:51pm. The waxing Moon shines between Jupiter and Saturn on Friday. The waxing crescent Moon, Jupiter, Saturn, and Antares follow a gentle arc about 35 degrees long in the southwestern sky after sunset.

On Saturday, first-quarter Moon occurs at 12:47pm. The first-quarter Moon shines with Saturn, only about 2 degrees to its right or upper right at dusk in eastern Sagittarius, near the handle of the “Teapot”. Saturn is 3,800 times farther away than the Moon. In a telescope, Saturn’s largest satellite, Titan, at magnitude 8.7, looks like an orange pinpoint, four ring-lengths to Saturn’s east.

Saturday is the International “Observe the Moon” Night. It is an annual worldwide public event that encourages observation and appreciation of the Moon. Dudley Observatory has stargazing, Moon observing, and other hands on activities that night. Check the “Dudley Observatory at miSci” website for details. This weekend is a good opportunity to explore the Moon. Try to locate two of the main features observed around this time of first-quarter Moon. On Saturday, Locate Lunar X near crater Werner. The Lunar X is a clair-obscur, a strong contrast between light and dark, effect in which light and shadow creates the appearance of a letter ‘X’ on the rim of the Blanchinus, LaCaille, and Purbach craters. The X is visible only for a few hours before the first quarter, slightly below the lunar terminator, the line dividing light and shadow on the Moon. The Lunar X can be seen around 11pm on Saturday.
On Sunday evening, try to locate the Lunar Straight Wall, or Rupes Recta, Latin for straight cliff. First look for the trio of large craters right in the center of the terminator’s surface, Ptolemaeus, Alphonsus, and Arzachel. Just to the southwest of Arzachel is a large ruined crater, flooded by lava from the Mare Nubium. The Straight Wall is a huge fault crossing this crater. When the Sun illuminates the feature at an oblique angle at about day 8 of the Moon’s orbit, the Rupes Recta casts a wide shadow that gives it the appearance of a steep cliff.

Get good views of Uranus during the late evening hours this weekend. The ice giant planet rises during twilight, and it climbs nearly halfway to the zenith in the east-southeast by 11pm. It reaches its peak some 60 degrees above the southern horizon around 2am. Uranus glows at magnitude 5.7 against the backdrop of southern constellation Aries the Ram. Use binoculars to find the planet 2.5 degrees due south of the similarly bright star 19 Arietis. A telescope reveals Uranus’ blue-green disk, which spans 3.7 arc-seconds.

Friday marks the anniversary of Sputnik satellite launch. The Space Age began on October 4 1957, as the Soviet Union launched Sputnik, the first manmade satellite, into orbit around the earth. The spacecraft circled the earth every 96 minutes at almost 18,000 miles per hour, 500 miles above the Earth. Sputnik stayed in orbit for about three months. The 184 pounds satellite had transmitted radio signal picked up around the world. Sputnik was 6 times the size of the first U.S. satellite, which was scheduled to be launched the next year. The first U.S. satellite, Explorer, was launched on January 31, 1958.

Skywatch Line for Wednesday, October 2nd, and Thursday, October 3rd, 2019

This is the Dudley Observatory Skywatch Line for Wednesday, October 2nd, and Thursday, October 3rd, written by Louis Suarato.

The 22% illuminated, waxing crescent Moon leads Jupiter and Saturn across the sky and sets at 9:21 p.m. Wednesday. Scorpius’ brightest star, Antares shines at magnitude 1.05 below, and forms a triangle with the Moon and Jupiter. Jupiter remains in the sky until 9:52 p.m., ahead of Saturn by about 2 hours. Mercury and Venus are side by side in the civil twilight sky, and set a half hour after sunset. Look low over the west-southwest horizon for the two innermost planets. Thursday night, the Moon and Jupiter will be separated by only 1 degree. Try to observe both in the same field of view through binoculars. Mars rises in the east, about 1 hour before sunrise.

Europa is the smallest of the four Galilean moons orbiting Jupiter, and the sixth-closest to the planet of all the 79 known moons of Jupiter. It is also the sixth-largest moon in the Solar System. Europa’s diameter is 1,940 miles, making it slightly smaller than our Moon. Europa’s icy surface makes it one of the brightest objects in the solar system. Europa is believed to have a metallic core, and a rocky core below its ice and water crust. This composition of materials indicate Europa was once entirely molten. Over time the heavier metallic materials sank to form the core, while lighter compounds floated to the surface, leaving the rocky material in between. Europa’s icy surface is scarred with cracks and ridges believed to have been caused by Jupiter’s tidal forces affecting its moon. The heating of its core, combined with the radioactive decay of rocky compounds, and the possibility of a liquid surface are conditions for biologic development. The European Space Agency is intrigued by this possibility and has proposed to launched a mission to Europa in 2022 called Icy Moon Explorer (JUICE).

Skywatch Line for Monday and Tuesday, September 30th and October 1st, 2019

This is the Skywatch Line for Monday and Tuesday, September 30th and October 1st, written by Joe Slomka.

The Sun sets at 6:39 PM; night falls at 8:13. Dawn breaks at 5:18 AM and ends with the Sun rising at 6:52.

Mercury and Venus are challenge objects just after sunset, southward of the Sun; Mercury is about 12 to the Moon’s lower right. Mercury is about 85% lit and shines with minus 2nd magnitude. Venus blazes with minus 4th magnitude, but much closer to the horizon. Since both are within the setting sun’s glare, binoculars are recommended; but observers are warned to carefully avoid looking at the Sun. Both set by 7:16 PM. If unsuccessful on these nights, both planets are will be higher and easier daily all October.

Jupiter and Saturn continue to be the only easily observed planets in the evening sky. Jupiter remains in Ophiuchus, glaring with minus 2nd magnitude and hovering about 20 above the horizon. It sets at 9:58 PM.

Saturn, in Sagittarius, glows with zero magnitude and lies about 24 high, it too is fairly low. However, Saturn is still worth turning a telescope on it. Saturn is nearing eastern quadrature, which means it appears 90 east of the Sun. The fact that the rings are tilted 25 to us, and with the Sun’s light shinng on the equator, the observer should experience an almost 3-D view. Saturn sets at 11:54 PM.

The Moon inhabits Libra on both nights. Monday’s 3-day-old Moon appears about 7% lit and flashes with minus 4th magnitude. Tuesday’s Moon appears fatter and brighter. It sets at 8:10 PM on Monday and at 8:44 PM on Tuesday.

Neptune continues to occupy Aquarius, shining with 8th magnitude and appearing as a tiny 2 arc-second dot. It is best observed at 11:30 PM and sets at 5:09 AM. Uranus is still in Aries, brighter with 5th magnitude and a bit larger in our telescopes. Uranus is highest at 2:30 AM and remains up the rest of the night. Finder charts from astronomy magazines and websites assist the observer.

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 under dark, rural skies. This is the “Wild Duck” cluster. Admiral Smyth gave it that nickname when he observed it and said it resembled “a flight of wild ducks.” 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. However, it shines with the brilliance of 10,000 suns.

Skywatch Line for Friday, September 27, through Sunday, September 29, 2019

This is Dudley Observatory’s Skywatch Line for Friday, September 27, through Sunday, September 29, written by Sam Salem.

On Friday, Sun rises at 6:48am and sets at 6:45pm; the waning crescent Moon rises at 5:03am and sets at 6:37pm. On Friday, the Moon reaches perigee, the closest point in its orbit around Earth, at 10:24pm. It lies 222,328 miles away from Earth. New Moon occurs at 2:26pm on Saturday. Because the Moon reached its closest point to Earth Friday evening, residents in coastal areas can expect higher than normal tides for the next few days.

The Moon’s absence from the morning sky these next two weeks is an excellent opportunity to view the zodiacal light. The time around the autumnal equinox is the best for viewing the elusive glow before sunrise. It appears slightly fainter than the Milky Way. You’ll need a clear moonless sky and an observing site located far from the city. Look for a cone-shaped glow that points nearly straight up from the eastern horizon, shortly before morning twilight begins.

Jupiter, at magnitude –2.1, lies between the feet of constellation Ophiuchus. Jupiter is the white dot low in the south-southwest as twilight fades away. It’s a poor season for observing Jupiter with a telescope as the planet is now sitting at low-altitude and as it has shrunk to just 37 arc-seconds wide. Jupiter sets a few minutes after 10:00pm. Saturn, at magnitude +0.4, sits in constellation Sagittarius. It lies 27 degrees upper left of Jupiter. Below Saturn is the handle of the Sagittarius Teapot. Barely above it is the dimmer, smaller bowl of the Teaspoon. Saturn sets a few minutes after midnight.

Try to spot Uranus unaided this weekend. Uranus, at magnitude 5.7, lies in constellation Aries. The planet is well up in the east by 11pm and highest in the south around 3am.

On Friday, try to locate planet Neptune. The planet sits in constellation Aquarius. Neptune appeared at its best at opposition earlier this month, but its visibility hardly suffers this week. The outermost major planet lies in the southeastern sky once darkness falls and climbs highest in the south around midnight. Neptune glows at magnitude 7.8, which is bright enough to spot through binoculars if you know where to look. Find the 4th-magnitude star Phi (φ) Aquarii, which lies about 15 degrees east-southeast of Aquarius’ distinctive Water Jar asterism. On Friday night, Neptune appears just 0.6 degrees west-southwest of Phi Aquarii. When viewed through a telescope, the ice giant planet shows a blue-gray disk.

The band of the Milky Way is tough to see unless you’re far from the artificial lights of the city and you’re looking on a night when the Moon is down. If you do look in a dark country sky, you’ll easily spot the Milky Way. Notice that it gets broader and richer in the southern part of the sky, in the direction of the constellations Scorpius and Sagittarius. This is the direction toward the galaxy’s center. The Lagoon Nebula, also known as M8 or Messier 8, is a large gas cloud within our Milky Way galaxy, barely visible to the human eye under good conditions. Bring your binoculars and look for M8 a few degrees above and to the right of the Teapot asterism in the constellation Sagittarius. Visually about three times the size of the full Moon, the Lagoon Nebula is the largest and brightest of a number of nebulosities in and around Sagittarius. Look for the Lagoon mid-summer to mid-fall. In September, the nebula crosses the meridian as darkness falls, making it prime for early evening observations.