Skywatch Line for Friday, January 15, through Sunday, January 17, 2016

This is Dudley Observatory’s Skywatch Line for Friday, January 15, through Sunday, January 17, 2016, written by Alan French.

The Moon reaches first quarter early Saturday evening, making this weekend ideal for observing the lunar landscape at a very reasonable hour. The Moon, slightly less than half full, will be due south and highest at 5:00 pm on Friday night. It will be due south at 5:53 pm on Saturday and at 6:46 pm Sunday.

As we’ve noted before detail stands out most near the terminator, the line dividing the sunlight portion of the Moon from darkness. As it moves from new to full this is the line of sunrise marching across the Moon. Along it shadows are long, so detail stands out exceptionally well. Even binoculars will shows some of the larger craters, and any telescope provides a memorable view. Although the features are unchanging, the lighting varies from hour to hour, greatly changing the appearance of the landscape.

The Lunar Reconnaissance Orbiter (LRO), which reached the Moon on June 23, 2009, was placed in a polar orbit for lunar mapping. In late 2010 the most accurate topographic map, based on date from the LRO, was publicly released. The LRO has also captured photographs showing the Apollo landing sites. These photos show evidence of our presence on the Moon, including the bases of the lunar landers, instruments left for lunar studies, and tracks left by the rovers.

You can see the LRO images of the Apollo landing sites at this web site.

At 9:30 pm bright Capella is high overhead. Capella is the sixth brightest star in the night sky and the closest first magnitude star to the pole. It is the brightest star in Auriga, the Charioteer. Including Capella, a rough pentagon of five stars marks the outline of Auriga.

If you are up not long before morning twilight infringes on the eastern sky, perhaps around 5:30 am, four planets stretch across the sky. Very low is brilliant Venus, a bit east of southeast. Higher and more toward the southeast is yellowish Saturn. To the south southeast is reddish Mars, and higher and toward to the south southwest is bright Jupiter.

On our faster, inner orbit, Earth overtakes and passes Mars about every two years and fifty days. Because of Mars’ eccentric orbit, the distance between the Earth and Mars varies. This year begins a series of relatively close approaches. From late April to late July Mars will be close enough for good telescope views. Unfortunately for those of us up here in the northern latitudes, the planet will be relatively low in the sky. Views through this thicker layer of the Earth’s atmosphere tend to be less steady and show less detail than when Mars is high in the sky.

Skywatch Line for Wednesday, January 13th and Thursday, January 14th, 2016

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

The 18% illuminated, waxing crescent Moon, appears in the constellation Aquarius high over the southwestern horizon after sunset Wednesday. Use binoculars or a small telescope to locate blue Neptune about 6 degrees below the Moon. Aquarius, meaning “water carrier” in Latin, is located between the constellations Capricornus and Pisces. Aquarius was one of the 48 constellations listed by the astronomer Ptolomy in the second century, making it one of the oldest recognized constellations along the Sun’s path, or zodiac. Aquarius is the 10th largest of the 88 modern constellations, covering an area in the sky of 979 square degrees. Its brightest stars are less than 2nd magnitude, with its brightest being Beta Aquarii, or Sadalsuud, at an apparent magnitude 2.91. Aquarius contains three Messier deep sky objects. M2 and M72 are globular clusters, and the third, M73 is an open cluster. You’ll find M2 about 5 degrees to the upper right of Sadalsuud. Several planetary nebulae can be found in Aquarius, including NGC 7293, the popular Helix Nebula, the closest planetary nebula to Earth at a distance of 650 light-years. 

Approximately 45 minutes after the crescent Moon sets, Jupiter rises in Virgo around 9:34 p.m. Wednesday night. At 11:18 p.m., Io will end its occultation, reappearing from behind Jupiter. Mars rises below Virgo’s brightest star, Spica, around 1:30 a.m. Thursday. Mars’ brightness improves considerably during the month, shining at magnitude 0.8 by month end. Saturn is up next, rising around 4:30 a.m. Thursday, followed by Venus about one half hour later. After their very close conjunction earlier this month, Saturn and Venus are now approximately 6 degrees apart and separating further each day. Mercury is at inferior conjunction, between the Sun and the Earth, and will reappears before sunrise in the southeast at the end of the month, 7 degrees below Venus. 

The Moon is at perigee, its closest distance to Earth during this lunar cycle, on Thursday at 9:14 p.m. at a distance of 229,671 miles. 

Thursday night may be a good time to locate Comet C/2013 US10 Catalina, weather permitting. The comet will be very close to the last star in the Big Dipper’s handle, Alkaid. Alkaidwill be about 20 degrees above the northeastern horizon after 10:30 p.m. Thursday night. Look 1 or 2 degrees to Alkaid’slower left. Visibility should improve as the comet rises above the horizon.

Skywatch Line for Monday and Tuesday, January 11th and 12th, 2016

This is the Skywatch Line for Monday and Tuesday, January eleventh and twelfth.

The Sun sets at 4:41 PM; night falls at 6:22. Dawn breaks at 5:44 AM and ends with sunrise at 7:29.

The twilight sky has one bright object, the Moon. Monday, the two-day-old Moon is rather low in the western sky and   inhabits Aquarius; it shines at minus 2.8 magnitude, appears only four percent illuminated and sets at 6:51 PM. Tuesday’s Moon is brighter at minus 5.4 magnitude, is about 10 percent illuminated and sets at 8 PM.

Neptune, Uranus and asteroid 4Vesta remain in their usual spots. Magnitude 7.9 Neptune resides in Aquarius, however nearby Tuesday’s Moon may overwhelm Neptune with its brightness; Neptune sets about 8:38 PM. Uranus is further from the Moon and, at magnitude 5.8, is visible in Pisces.

Uranus sets at Midnight. Asteroid 4Vesta lies about eight-and-a-half degrees above the star Iota in Cetus, and sets after 11 PM.  All three require finder charts from astronomy media.

By 10 PM, the sky changes shifts. Jupiter is just risen in Leo and Comet Catalina is closing in on the Big Dipper, which also just rose. Monday night, Catalina shines about magnitude six and is about six-and-a-half degrees above the horizon. Tuesday places it about nine degrees high. The comet is about 4 degrees from the star Lambda Bootis, and about six degrees below the star Alkaid, the last star in the Big Dipper’s handle.

Midnight finds Jupiter moderately high in the eastern sky. While binocular users can see the planet and Galilean moons, telescopic observers can see the Great Red Spot (a giant storm) at 2:26 AM on Tuesday. They can also witness the Jovian moon Io being eclipsed by the planet at 1:29 AM.

Also on Tuesday, Io’s shadow begins to cross the planet’s face at 10:50 PM, followed by the moon itself at 11:54 PM; the shadow exits Jupiter at 1:05 AM Wednesday, followed by the planet itself at 2:08.

Jupiter continues to lead the planetary parade. Red planet Mars shines at first magnitude near the star Kappa in Virgo. Saturn rises at 4:32 AM, and is about ten degrees above the horizon at Astronomical Dawn. While the zero magnitude planet is binocular visible, it takes a telescope to fully perceive the beauty of its ring system. Venus shares Ophiuchus, rising at 4:50 AM about four degrees below Saturn. At minus four magnitude, Venus is certainly visible to the naked eye, but telescopes reveal it about 80 percent illuminated.

Skywatch Line for Friday, January 8, through Sunday, January 10, 2016

This is Dudley Observatory’s Skywatch Line for Friday, January 8, through Sunday, January 10, 2016, written by Alan French.

The Moon reaches new early Saturday evening, so this weekend’s skies will be dark and moonless. Watch for the slender young Moon as it returns to the evening western sky early next week.

At 6:30 am on Saturday morning Saturn and Venus will be very close together in the southeast. They will be just under one-half degree apart, less than the apparent diameter of the Moon. Fainter Saturn will be to the upper right of Venus. The rapid motion of Venus among the stars will speedily move them farther apart over the next few days. By Sunday morning the distance between the pair will have increased to one and a half degrees. By Monday they will be two and a half degrees apart.

If you’re up a bit earlier on Saturday morning, watch the International Space Station (ISS) as it passes low across the northern sky. The station will first appear at 5:58:23 am when it will emerge from the Earth’s shadow in the north northwest when 28 degrees above the horizon. It will travel eastward across the northern sky, passing above the conspicuous “W” of Cassiopeia, the Queen, and then vanish below the northeastern horizon at 6:01:29.

In the evening the Pleiades, also known as the Seven Sisters, is well up in the sky. Look for it high in the southeast at 8:00 pm. The cluster has the shape of a small dipper, and is above and somewhat to the right of bright, reddish Aldebaran.

To the eye, the Pleiades is a lovely sight, but under our dark moonless weekend skies binoculars will reveal many more stars, transforming it into a real celestial showpiece. It is one object that is often best seen in binoculars. Their wide field of view will show the entire cluster surrounded by darker, less star strewn sky. Most telescopes do not show enough sky to encompass the entire cluster in one view.

The Pleiades has been known since antiquity. Homer wrote about it in the Iliad and Odyssey. To some Greek astronomers its stars formed a distinct constellation. In Japan it is know as “Subaru,” and you can recognize the cluster in the company’s logo, visible on their cars.

As early as 1676 Reverend John Mitchell realized the stars in the cluster must be physically related by calculating that the odds were strongly against so many bright stars being close together in a chance alignment. Comet hunter Charles Messier included the Pleiades in his catalog of deep sky objects. As the 45th object on his list amateur astronomers often refer to it as M45. Whatever you call it, it’s one of the finest sights in our night sky.

Skywatch Line for Wednesday, January 6th and Thursday, January 7th, 2016

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

On January 7, 1610, Galileo wrote that there were “three fixed stars, totally invisible by their smallness” that were extremely close to Jupiter. On January 10, 1610, Galileo noticed a fourth “star”. After observing these celestial objects over a longer period of time, Galileo realized the objects were orbiting Jupiter. The first three objects were the moons Callisto, Io, and Europa. The fourth object was Jupiter’s largest moon, Ganymede. Galileo’s discovery, that there were objects orbiting something other than Earth, led to the heliocentric model of the solar system, which theorized that all planets orbited the Sun. Jupiter rises at 10:13 p.m. Wednesday in the constellation Leo. By midnight, Io will be closest to Jupiter on one side, next to Europa, and much farther away, on the same side, will be Callisto. Ganymede will be alone on the other side of Jupiter.

Arcturus will be rising low on east-northeastern horizon around 1 a.m. Thursday. The globular cluster, M3, will be approximately 12 degrees above Arcturus. Comet C/2013 US10 Catalina can be found about 7 degrees to the lower left of M3. At 5:00 Thursday morning, Venus rises, followed by Saturn 10 minutes later. Look left of Saturn for the 8% illuminated, waning crescent Moon. Friday morning, Venus and Saturn will be less than two degrees apart. Saturn’s rings are now tilted 26 degrees from edge on and provide a beautiful, but early, telescopic view. Mercury, which is barely visible 5 degrees above the horizon after sunset, will reappear in the morning sky in the final week of January.

The Dudley Observatory has posted its 2016 Calendar of  Events. These are events that are open to the public. You can access the calendar by clicking on this link:



Skywatch Line for Monday and Tuesday, January 4th and 5th 2016

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

The Sun sets at 4:34 PM; night falls at 6:16. Dawn breaks at 5:44 AM and ends with sunrise at 7:26.

After sunset, the sole bright planet is Mercury. It appears about eight degrees above the southwestern horizon.
Binoculars or telescope help find it amid the sky glow. Under high powers it appears about one-third illuminated. This is a very favorable apparition for observers. It is virtually stationary between the first and the ninth of January before beginning to descend.

Outer planets Neptune and Uranus still occupy their stations in Aquarius and Pisces. Neptune sets at 9:05 PM, while Uranus sets at 12:25 AM. Asteroid 4Vesta lies about six-and-a-half degrees above the star Iota Ceti.  All three require finder charts, found in astronomy websites, magazines and apps, to locate these small dim objects.

Constellation Leo is risen by Midnight, and so is Jupiter, hovering between Leo and Virgo. The planet glows at minus 2.2, easily visible to the naked eye, and begins a planetary parade. While binocular users can see the Galilean Moons, telescopic watchers can see the Great Red Spot at 2:14 AM on Tuesday and 3:52 AM on Wednesday. They can witness the moon Ganymede’s shadow begin to cross Jupiter’s face at 11:18 PM on Monday, and exit Jupiter at 2:36 AM, Tuesday. The Moon Ganymede itself begins crossing Jupiter at 3:56 AM. Jupiter is best observed at 4:34 AM, Tuesday.

Comet Catalina is heading back to the outer Solar System. It hovers about seven-and-a=half degrees above the bright star Arcturus in Bootes. Astronomers describe it as about magnitude 6.5.

Mars rises next, at 1:31 AM, in Virgo. It gradually brightens and grows larger this year. It appears as a first magnitude rust-colored dot below Spica.

The 25 day-old waning Moon rises in the pre-dawn. Tuesday finds it in Libra and Wednesday in Scorpius.

Venus rises at 4:35 AM in Scorpius. In binoculars or telescope, it blazes at minus fourth magnitude, and appears about three-quarters illuminated. Three degrees below Venus, Saturn rises at 4:56 AM – the rear guard of the procession. It shines as a cream-colored star of magnitude 0.5. While binoculars show it as an oval planet, telescopes reveal its magnificent ring system and fleet of moons. In coming months, Saturn will rise earlier and become more accessible to casual observers.

A new year means new calendars on our walls. Until 1582, the calendar Julius Caesar adopted was still in effect. It was increasingly apparent that the calendar was out of step with civil and religious seasons. A little known Italian doctor, Aloysius Lilius, wrote a letter to the Pope pointing out this problem. An initially skeptical Cardinal Christopher Clavius saw the wisdom of Lilius’ solutions and championed them before the newly elected Pope. The Pope declared the reformed calendar effective on October 15, 1582. Catholic countries quickly adopted the change, even though people “lost” 10 days that year. Slowly other countries adopted it – the last being communist China in 1949. Alas, Lilius is almost forgotten, while the calendar was named for the Pope and a major crater on the Moon enshrines Clavius.

Skywatch Line for Friday, January 1, through Sunday, January 3, 2016

This is Dudley Observatory’s Skywatch Line for Friday, January 1, through Sunday, January 3, 2016, written by Alan French.

Happy New Year! We hope 2016 is a good year for you, and filled with clear, starry nights!

Reaching last quarter very early on Saturday, the Moon rises after midnight this weekend, leaving the evening sky moonless and dark.

This first weekend of 2016 is your best chance of spotting Mercury for its current evening appearance. Look for the innermost planet at 5:15 pm low toward the west southwest. It will be 7 degrees above the horizon, so you’ll need a good view and skies clear of haze and clouds down to the horizon. (For reference, a fist held at arm’s length spans 10 degrees across the knuckles.) As the minutes pass the skies will grown darker, but Mercury will also be moving closer to the horizon. Mercury sets just after 6:00 pm.

The aurora or northern lights is arguably one of the most impressive celestial sights visible to the unaided eye. Here in the Capital District we are too far south for such displays to be common, but far enough north for them to occur occasionally. The best way to catch a display that does make it this far south is to keep an eye on the northwestern to northern skies, and to watch for news of possible aurora on the Internet.

A display often begins as a gentle glow low in the northwest, so a good view in that direction and a location away from city lights will help spot early signs of aurora. As the display becomes more active it moves higher into the sky, and there are often shafts of light that extend well up from the horizon. An active display, well down into the northern states, can fill the northern sky with curtains of light. Some displays are relatively static, while others are more active, with pulsations of light moving across the sky.

Modest displays may not show color, while a bright, active aurora can show vivid reds and greens. If the show pushes well into the United States it can cover the entire sky.

The Spaceweather website is an excellent source of information about chances for northern lights. They report CMEs, Coronal Mass Ejections, which can send high energy particles toward Earth and potentially trigger a display. If you scroll down the page you’ll find probabilities for a geomagnetic storm at mid-latitudes on the left side. Watch for high chances for major storm activity and keep an eye on the skies on such nights.

Let’s hope 2016 treats us to some fine displays of the northern lights!

Skywatch Line for Wednesday, December 30th and Thursday, December 31st

This is the Dudley Observatory Skywatch Line for Wednesday, December 30th and Thursday, December 31st written by Louis Suarato

Celebrate your year-end by seeking out the innermost planet, Mercury, about 40 minutes after sunset. Look approximately 5 degrees over the southwest horizon to catch Mercury before it sets around 5:40 p.m. below the constellation Capricornus. Mercury orbits the Sun once every 88 days, and rotates on its axis three times during two revolutions around the Sun. Of all the planets, Mercury’s orbital eccentricity is the greatest, as its distance at aphelion is 1.5 times farther from the Sun as it is at perihelion. 

The bright stars comprising the asterism known as the Winter Circle, or Winter Hexigon, can be seen after 8 p.m. over the eastern horizon. The lowest star in the circle is also the brightest. That star is Sirius, in the constellation Canis Major. To the east of Sirius is Procyon, the brightest star in the constellation CanisMinor. Above Procyon is Pollux, in Gemini. Continuing clockwise, you’ll find Capella, in the constellation Auriga. Below, and south of Capella, is Taurus’ brightest star Aldebaran. Completing the circle is Rigel, in the constellation Orion. 

The planetary procession continues when Jupiter rises at 10:40 p.m. just below the 68% illuminated, waning gibbous Moon. You may be able to see Jupiter in the daylight by using the Moon as a guide when it passes 1.5 degrees south of Jupiter at 1 p.m. EST on December 31st. Mars follows Jupiter about three hours later in Virgo. Another three hours later, Venus rises at the head of the scorpion, followed by Saturn an hour later. If you were successful in seeing Mercury, you’ll have an opportunity to see all the easily visible naked-eye planets. 

The Big Dipper will be standing upright on its handle high over the eastern horizon during the pre-dawn hours. Follow the arc of the handle downward toward Arcturus. Use Arcturus to find Comet C/2013 US10 Catalina just 3 degrees to its right. 

Skywatch Line for Monday and Tuesday, December 28th and 29th

This is the Dudley Observatory Skywatch Line for Monday and Tuesday, December 28th and 29th written by Joe Slomka.

The Sun sets at 4:28 PM; night falls at 6:11. Dawn breaks at 5:43 AM and ends with the Sun rising at 7:25.

The twilight sky contains the planets Uranus, in Pisces, and Neptune, in Aquarius. They become visible as twilight gives way to night. Mercury blazes at magnitude minus 0.5 about eight degrees above the southwestern horizon. Binoculars may help find Mercury amid the sky glow. Mercury sets at 5:57.

Night finds the asteroid 4Vesta, in Cetus, joining Uranus and Neptune. While Uranus is bright enough for binoculars, all three require detailed finder charts for location. These charts are available from astronomical magazines, websites and apps. Uranus is best observed at 6:24 PM, and sets at 12:53 AM. Neptune sets at 9:32 PM. Vesta sets at 11:42 PM.

The eighteen-day-old waning Moon rises at 8:11 PM on Monday, near Leo’s front paw and appears about 85 percent illuminated. Tuesday, the slimmer crescent, rises at 9:11 PM near Leo’s forward rear leg.

Jupiter rises at 10:21 PM between Leo’s tail and Virgo’s head. It begins a pre-dawn planetary parade. Telescopic observers can see Jupiter’s Great Red Spot, a giant storm, at 5:36 AM Tuesday and 1:28 AM Wednesday. They can also witness the Jovian moon Ganymede’s shadow beginning to cross the planet’s face at 12:09 AM Tuesday and exit at 3:26 AM. The moon Io reappears from behind Jupiter at 1:11 AMalso Tuesday.

The term ecliptic is heard many times on the Skywatch Line.
The Dawn sky dramatically demonstrates it. Go out about 5:45 AM and look southeast. On both days, a waning Moon is high in Leo. Look to the lower right, and find Jupiter, Mars, Venus and Saturn. One can draw a straight line through these heavenly bodies. This line is the ecliptic – the path of the Sun, Moon and planets across the sky. Mars lies in in Virgo, near the bright star Spica. Venus is in Libra and newly risen Saturn is in Ophiuchus.

Comet Catalina follows its own path. It is about four degrees below the bright star Arcturus in Bootes. Recent reports have the comet shining at about magnitude 6.3, visible through binoculars under good conditions.

Since Saturn is a feature of our Dawn sky. Let us consider his importance. This time of the year was dedicated to Saturn, the Roman God of Harvests. A series of feasts were held during the week of the Winter Solstice – the Saturnalia. Saturn was depicted as a jolly old man. People decorated evergreen trees. Candles were lit everywhere. Houses were decorated with wreaths and Holly. Decorated cookies were baked. People wore red peaked hats, similar to the “Santa hats” of today. Banquets were held both in honor of the harvest and wishing for a prosperous new year. Gifts were exchanged: dolls for the children, candles and fruits for the adults. Benefits were held for he poor. Saturnalia was an official government holiday. The holiday was so popular that Christians moved the feast of Christ’s birth to compete and adopted many of the symbols and traditions of this pagan feast.

The Dudley Observatory and Albany Amateur Astronomers wish their followers Happy Holidays.

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

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

The 97% illuminated, waxing gibbous Moon rises around 3:00 Wednesday afternoon. It was on December 23, 1968, that American astronauts Frank Borman, James A. Lovell, Jr., and William Anders, became the first men to orbit the Moon. The Apollo 8 mission was not only the first manned flight to the Moon and back, but it served to survey potential landing sites for the first lunar landing. At nightfall, you’ll see that the Moon resides in Taurus, about three degrees from the constellation’sbrightest star, Aldebaran. Aldebaran is sometimes mistakenly considered part of the Hyades Star Cluster, but at the distance of 65 light-years, Aldebaran is much closer than the stars of the Hyades, which are about 150 light-years away. Similar to using Orion’s belt to find Sirius, the brightest star in our sky, you can follow the Belt in the other direction, and the first bright reddish-orange star you’ll see is Aldebaran. The Pioneer 10 spacecraft is headed in Aldebaran’s general direction and should be in its vicinity in about 2 million years.

Jupiter appears above the horizon around 11 p.m. at the top of the constellation Virgo. Comet C/2013 US10 Catalina rises between Arcturus and Mars around 1:30 a.m., and at approximately 4:30 a.m., the comet will be about 30 degrees above the east-southeastern horizon. The bright star to the lower right of Mars, is Spica, the constellation Virgo’s brightest. Venus rises 11 minutes after 4 a.m., followed by Saturn an hour and 40 minutes later. 

December’s Full Moon occurs at 6:11 a.m. Christmas Day. This month’s Full Moon is known as the Full Cold Moon and the Long Night Moon. The Long Night Moon is derived from the Full Moon closest to the winter solstice, when, because of the axial tilt of the Earth, the Full Moon crosses the sky higher than any full Moon of the year. The Moon will be at its highest around midnight, and being closer to perigee than average, will add brightness to objects below. The Full Moon will be visible from Thursday at 3:54 p.m. until Friday at 6:55 a.m., a full 15 hours.