Skywatch Line for Wednesday, March 9th and Thursday, March 10th, 2016

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

The 1% illuminated, waning crescent Moon will be a challenge to see as it sets an hour after the Sun on Wednesday. The crescent Moon will be easier to see when it is 5% illuminated, and higher above the horizon after sunset Thursday evening. The moonless sky offers its evening highlights early as Jupiter climbs above the eastern horizon. Jupiter reached opposition Tuesday, and shines at magnitude -2.5. As you look at Jupiter’s Galilean moons throughout the night, you’ll notice Ganymede and Io to one side and Europa and Callisto on the other side, all moving away from the planet. Thursday night, Jupiter’s Great Red Spot, a 200 to 400 year old storm, twice as large as planet Earth, begins its transit at 8:30. This storm, with winds peaking at 400 miles per hour, orbits the planet counter-clockwise, with a period of about six days.

Mars rises between Libra and Scorpius around midnight. Earth and Mars are moving toward each other, by 25,954,000 miles, until Mars reaches opposition on May 22nd. Saturn rises in the constellation Ophiuchus after 1 a.m. Thursday. Rising alongside Saturn, to its right, is the globular star cluster NGC 6235, also known as Mel 154. Ten degrees to the right of NGC 6235 is the globular star cluster M4. The distance between Mars and Saturn is also closing, from 18 degrees to 9 degrees throughout March. Venus joins the morning planets, rising at 5:30 Thursday.

There will be a bright International Space Station pass over our region early Thursday morning. The ISS will appear in mid-sky, between the handle of the Big Dipper and Arcturus, at 4:39 a.m., and travel toward the northeast horizon.

The Moon reaches perigee, the closest to Earth during this lunar cycle, at 2:04 a.m. Thursday, at a distance of 223,389 miles.

Skywatch Line for Monday and Tuesday, March 7 and 8, 2016

This is the Skywatch Line for Monday and Tuesday, March seventh and eighth.

The Sun sets at 5:53 PM; night falls at 7:27. Dawn breaks at 4:44 AM and ends with sunrise at 6:18.

The Moon turns “New” Tuesday evening and is not seen either Monday or Tuesday evening.

The darkening sky contains only one bright planet – Jupiter. Jupiter rises at 5:45 PM and is found near Leo’s hind leg. Jupiter is at opposition Tuesday morning and sets shortly after sunrise. While binoculars readily show Jupiter and its four Galilean moons, telescopes present an exciting sight Monday evening – two shadows on its face. The satellite Europa and its shadow began their trek across the planet during Jupiter’s rise. At 7:28 PM, the shadow of the moon Io joins Europa’s, followed by Io itself. Both shadows can be seen through most amateur telescopes. Europa and its shadow exit Jupiter at 8:58 PM.  Io and its shadow exit at 9:43 PM. Telescopic observers can also see the Great Red Spot, a giant storm, on Jupiter at 12:13 AM and 8:04 PM Tuesday.

The planet Uranus still inhabits Pisces. However it is quite low in the western sky and sets at 8:28 PM.

Midnight sees Jupiter at is highest and best observed around Midnight. Meanwhile, Mars rises before Midnight. Mars is now at zero magnitude and also growing bigger in our binoculars and telescopes.

Saturn joins the scene by rising at 1:10 AM in the dim constellation Ophiuchus. It is slightly dimmer than Mars, but its cream white orb stands out amid the stars. Saturn’s rings are not to be missed, especially by first time sky watchers.

Venus rises before Civil Dawn. It appears very low on the eastern horizon; an unobstructed view may be necessary to find it. Venus blazes at minus 3.9 magnitude and is 92 percent illuminated.

If you observe from a rural dark site, Jupiter is about 18 degrees to the left of a dim roughly triangular small constellation. This constellation is Sextans.

Most constellations are related to mythical people or objects. In the 16th and 17th centuries, new constellations were devised to celebrate newly discovered star patterns and high technology of the times.  One of these constellations is Sextans, the Sextant. Sextans is found between Leo’s front paws and the constellation Hydra.

Johannes Hevelius was a Polish astronomer in the port city of Gdansk (also known as Danzig).  Prominent in local politics, his true passion was astronomy. In 1641, he built a private observatory that included a 150-foot telescope. However, he did most of his work with a six-foot brass sextant. He was inducted into Britain’s Royal Society in 1664.  A sextant contains an arc, one-sixth of a circle. It has a moveable arm that permits measurement of angles. In 1679, fire destroyed his observatory.  He immortalized his loss with an invented constellation, Sextans, and rebuilt his observatory.  Sextants still exist. Sailors use a version that includes a small telescope on the swinging arm and mirrors. Along with an accurate clock and astronomical almanac, the navigator locates his position at sea. That skill is being lost to the increasing use of GPS to fix a position with unprecedented accuracy.

Skywatch Line for Friday, March 4, through Sunday, March 6, 2016

This is Dudley Observatory’s Skywatch Line for Friday, March 4, through Sunday, March 6, 2016, written by Alan French.

The Moon reached last quarter last Monday and is now moving toward new, which occurs this coming Tuesday. A slender old Moon will grace the morning sky before sunrise.

At 5:30 AM on Saturday morning a 17-percent illuminated crescent Moon will be low in the southeast, just under 14 degrees above the horizon. At the same time Sunday morning, an even thinner crescent – just 9-percent in sunlight, will be just over 7 degrees above the horizon in the east southeast.

The dark moonless skies this weekend are ideal for enjoying the beauty of the winter sky before it vanishes in the west. At 8:00 PM the familiar bright stars of winter are almost due south, with brilliant Sirius, the brightest star in the night sky, 30 degrees above the horizon.

Sirius is bright mostly because it is a nearby neighbor, lying at a distance of just 8.7 light years. With a luminosity of a bit over twenty times that of our Sun, it is pretty typical of the stars we see.

It can be hard to get a real concept of the vastness of space and the large distances between our solar system and even our nearest neighbors. A popular model of our solar system begins with a Sun the size of a bowling ball. On this scale our Earth is the size of a peppercorn and is 26 yards from the bowling ball Sun. The farthest planetary member of our solar system, Neptune, would lie 778 yards away and be the size of a peanut.

When we start adding the nearby stars to our model, the distances grow much larger. In our model, Sirius would lie 8,070 miles away. The nearest star in our nighttime sky, Proxima Centauri, would be 4,000 miles from our bowling ball Sun.

If you are away from the light polluted skies of our cities and larger towns, look for the band of light that marks the winter Milky Way, stretching upward a bit east of due south, passing east of Sirius, up above Orion, and passing west of bright Capella high overhead. The Milky Way narrows and dims past Capella, then brightens and broadens as it move down toward the north northwestern horizon.

In the winter we are looking outward in our galaxy, away from its center. The region of Taurus and Auriga, where you see a marked dimming, is directly away from the galactic center. Largely because there are fewer stars in the outer part of the galaxy, this part of the Milky Way is faint.

The region passing through the conspicuous “W” pattern of stars marking Cassiopeia is quite rich in stars. It’s a wonderful area to explore with binoculars, especially from the comfort of a lawn chair.

Skywatch Line for Wednesday, March 2nd and Thursday, March 3rd, 2016

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

You don’t have to stay up late to see some wonderful objects in this week’s night sky. With the waning crescent Moon below the horizon until 2:14 a.m. Thursday, you’ll have darker skies to find these binocular and telescopic targets. Jupiter rises conveniently at 6:11 p.m. Thursday evening. You may want to wait until rises higher to observe it though, when the giant planet rises above the atmospheric turbulence. A small telescope will reveal Jupiter’s largest moons, known as the Galilean Moons. At around 8 p.m., Jupiter’s largest moon, Ganymede, will be close to Io on one side, with Callisto further away. Europa will be alone on the other side.

Beyond Jupiter, further along the ecliptic, is the constellation Leo’s brightest star, Regulus. Beyond Regulus, before you reach Castor and Pollux in Gemini, in Cancer is M44, or the Beehive Cluster. This beautiful binocular target is one of the nearest open clusters in our solar system. In 1609, Galileo became the first to target M44 with a telescope. Galileo was able to resolve 40 stars through his 8 power telescope. Charles Messier added the Beehive Cluster to his catalog in 1769. The constellation Orion should be easy to see to the west of Gemini, even in light polluted skies. Just below the star to the left in Orion’s Belt, is the Great Orion Nebula, or M42. M42 is one of the brightest nebulae in the night sky. It is visible to the naked eye, but your exploration of the object improves as you view it through binoculars, then through a telescope. The Great Orion Nebula is the object of intense study of how star systems are formed. Evidence of this is the young open cluster at the center known as the Trapezium. Depending on the power of your telescope, and the quality of the seeing, you may be able to resolve 4 to 6 stars at the center of the nebula.

When Luna does make an appearance in the early morning hours, it will rise as a 35%, illuminated, waning gibbous Moon. If you look at the shadowed side of the Moon with binoculars, you’ll notice the stars of Open Cluster M23 nearby. Further along the ecliptic will be Saturn, then Mars.

Skywatch Line for Monday and Tuesday, February 29th and March 1st, 2016

This is the Skywatch Line for Monday and Tuesday, February 29th and March 1st.

The Sun sets at 5:44 PM; twilight ends at 7:18. Dawn begins at 4:56 AM and ends with the Sun rising at 6:30.

The darkening sky contains only one planet, Uranus, and one asteroid, Vesta. Uranus appears as a blue-green dot in Pisces. The minor planet, 4 Vesta, lies about 8 degrees east of Uranus; it also lies about five degrees from the star Alpha Piscium, also known as AlRischa. Both Uranus and Vesta require star charts from astronomy media. Uranus sets at 8:54 PM, Vesta at 9:30.

Jupiter rises during twilight, and, by nightfall, is moderately high in the eastern sky. At magnitude minus 2.5, it is the brightest object in Leo, appearing near the Lion’s rear leg. Jupiter will reach opposition on March 8th.  Opposition means that Jupiter is at its brightest, closest, largest and stays up all night. While Jupiter is best seen through a telescope, moderately powerful binoculars can also provide views of its moons. Telescopic viewers can see, at 10:08 PM Monday, Jovian moon, Callisto, cast its shadow on the planet, followed by the moon itself at 12:22 AM, Tuesday. Callisto’s shadow exits at 1:16 AM, followed by Callisto itself at 2:16 AM. Jupiter is best observed at 12:40 AM.

Mars rises shortly after Midnight. It appears as a red dot in Libra. The planet now shines at zero magnitude and slowly grows larger in our telescopes. It is best seen at about 5 AM. Tuesday’s Moon rises shortly after Mars. It turns Last Quarter at 6:11 PM and blazes at minus 10 magnitude near the head of Scorpius. Wednesday, it rises at 1:21 AM, dims slightly and parks itself near Saturn in Ophiuchus. Saturn rises at 1:36 AM and shines at zero magnitude. During March, Mars closes in on Saturn.

Venus rises at 5:32 AM and blazes at minus 4 magnitude. However, it hovers only four degrees above the eastern horizon. In telescopes, it appears about 91 percent illuminated.

Monday is February 29. When most months have 30 or 31 days, why does February have 28 or 29? The old Roman calendar was a lunar calendar of ten months containing 304 days. There was no standard system for inserting “leap months.” The result was chaos. While Julius Caesar was in Egypt, he met Sosigenes, a prominent mathematician, who suggested reforms to the Roman calendar.

Julius Caesar adopted those reforms that resulted in the current system of twelve months containing 365 days and leap years. Months contained 30 or 31 days. What is less well known is that he shifted a day from February to the newly named month of July (after himself). Augustus, his successor, also borrowed a day from February, so that August (his month) would be equally as long as July’s.

Skywatch Line for Friday, February 26, through Sunday, February 28, 2016

This is Dudley Observatory’s Skywatch Line for Friday, February 26, through Sunday, February 28, 2016, written by Alan French.

Reaching full last Monday, a waning gibbous Moon rises late in the evening this weekend. The Moon rises at 9:36 PM on Friday, 10:33 PM on Saturday, and 11:29 PM on Sunday. It reaches last quarter this coming Tuesday.

Bright Jupiter now rises in the east close to 6:30 PM and is due south and highest just before 1:00 AM. Although detail on the planet is best observed around 1:00 AM, when the telescope is looking highest and through the thinner possible layer of our atmosphere, its four bright Galilean moons are easy to view during the more agreeable evening hours.

Even a modest telescope will show the four largest moons, Io, Europa, Ganymede, and Callisto. The moons look like stars, roughly in a line, and may lie on either side of the planet. From our viewpoint, as they orbit Jupiter, they appear to shuttle back and forth, passing in front of the planet as they move from east to west and behind it as they move from west to east. (The other 63 moons orbiting Jupiter are essentially beyond the reach of amateur telescopes, although Himalia is within the reach of experienced amateur astronomers with large telescopes.)

The moons themselves can be hard to see when they cross in front of Jupiter, but they cast shadows onto Jupiter’s cloud tops, and these inky black spots are fairly easy to spot through a telescope magnifying about 60 times, typical of many spotting scopes and small astronomical telescopes. Larger telescopes and higher magnifications are needed to see the moon itself in front of Jupiter – and even then the moon can prove hard to see.

At 9:30 on Friday evening you’ll find three moons stretched out to one side of Jupiter and one lone moon on the opposite side. The string of three moons, in order of their distances from Jupiter, consists of Io, Europa, and Ganymede. The lone moon is Callisto.

At 9:30 PM on Saturday night you’ll see only three moons, and one may be hard to spot. Io and Callisto will be on one side and the third, Ganymede, will be on the same side by very close to Jupiter, having just emerged from behind the planet, and perhaps hard to spot. Europa is passing behind the planet and out of sight. It will emerge, on the east side, at 9:08 PM.

If you stay up late, the shadow of Io will move onto Jupiter at 11:06 PM, appearing as an inky black dot. Io itself will move in front of Jupiter at 11:20 PM. Although we’ve said the moons can be hard to spot in front of the planet, it’s often easier to see one just as it moves in front of Jupiter.

If you look at 9:30 PM Sunday night you’ll see only three moons, forming a triangle, to one side of the planet. The closest to Jupiter is Europa, the brighter of the other two is Ganymede, and the third is Callisto. Io will be passing behind the planet and out of sight.

It’s fun and easy to watch the dance of the Jovian moons. I hope you’ll try it!

Skywatch Line for Wednesday, February 24 and Thursday, February 25, 2016

This is the Dudley Observatory Skywatch Line for Wednesday, February 24th and Thursday, February 25th written by Louis Suarato

The 95% illuminated, waning gibbous Moon rises in the constellation Virgo at 7:42 p.m. Wednesday night, about an hour after Jupiter can be seen over the eastern horizon. Planet and Moon will be separated by about 13 degrees. Jupiter is approaching its peak brightness for the year as it reaches opposition, the position from our sky opposite the Sun. At that time, Jupiter will also be at its closest to Earth. As Jupiter rises on March 8th, it will be 413 million miles away. Look for Jupiter’s brightness to increase to -2.5 magnitude during that time. As Jupiter and the Moon are rising, the southern to western area of the sky will be filled with bright stars. Above the southern horizon will be Sirius, the brightest star in the constellation Canis Major, and the brightest star in our sky. The constellation Orion occupies a significant area of the sky west of Canis Major. Look for Orion’s brightest stars, Betelgeuse, at the hunter’s left shoulder, and Rigel, below the hunter’s belt. West of Orion is Taurus, and its brightest star, Aldebaran. You’ll find the Pleiades star cluster just west of Aldebaran. A wide angle camera lens, such as a15 millimeter, will enable you capture the southern to western sky, from Sirius to the Pleiades.

The last week in February and first week of March are good times to view the Zodiacal Light after evening twilight. The Zodiacal Light is a faint conical glow over the western horizon caused by sunlight reflecting off millions of particles of interplanetary cosmic dust. At its base, close to the western horizon, the Zodiacal Light is brightest, at approximately -8.5 magnitude. As the light stretches toward the zenith, it becomes much fainter. To see the Zodiacal Light, you should travel to a dark sky site away from urban, light polluted skies. Any of the Albany Area Amateur Star Party sites, such as the Landis Arboretum of Grafton Lakes State Park, would be ideal locations for viewing the Zodiacal Light.

Skywatch Line for Monday and Tuesday, February 22 and 23, 2016

This is the Dudley Observatory Skywatch Line for Monday and Tuesday, February 22nd and 23rd written by Joe Slomka.

The Sun sets at 5:35 PM; night falls at 7:08. Dawn begins at 5:07 AM and ends with sunrise at 6:41.

The twilight sky contains only Uranus and the Moon. The Full Moon rises ten minutes after sunset. Native Americans of the Northeast had names for the Moons of different seasons. This Full Moon was called the “Snow Moon,” since the usually deep snow hampered hunters. Some tribes called it the “Hunger Moon,” also because it impeded hunters trying to find food for their tribe. The Moon sets at 7 AM Tuesday, and 7:30 AM on Wednesday. Monday night, the Moon hovers beneath Leo’s belly. Tuesday finds it two degrees away from Jupiter near Leo’s hind leg.

Uranus can be found at nightfall in Pisces. It appears as a sixth magnitude dot in our telescopes. It requires finder charts from astronomical magazines, websites and apps and sets by 9:45 PM.

Jupiter rises after the Full Moon. Jupiter is one of the few objects that resist the lunar glare. While binocular users can see the planet and its Galilean moons, telescopic observers can see weather bands on Jupiter and the Great Red Spot, a giant storm. The Great Red spot can be seen at 9:34 PM on Monday, and at 3:21 AM on Wednesday. They can also see the moon Ganymede cast its shadow on Jupiter at 2:56 AM Wednesday, followed by the moon itself at 4:17 AM. Jupiter is best seen at 1:11 AM and sets at 7:32 AM.

After Midnight, Mars rises at 12:23 AM. Zero magnitude Mars still inhabits Libra. It should be an obvious red dot amid the dim constellation. Saturn rises at 2:02 AM in Ophiuchus. Its cream color should distinguish it from surrounding stars, and its eight degree separation from Antares, the bright red star in Scorpius, helps find it. Venus, rises at 5:35 AM, blazes at minus 4 magnitude and occupies Capricornus. In telescopes, it appears about 90 percent illuminated. Mercury is last, rising at 5:55 AM. It is only two degrees above the horizon. A sky watcher should use brilliant Venus as a start, and look five degrees below to find the minus 0.4 magnitude planet. An unobstructed horizon assists in finding both Venus and Mercury.

After sunset, the giant constellation Orion appears. Canis Major, the Big Dog, follows at Orion’s heels. Sirius, the Dog Star and its brightest star, is the seventh closest star to our Solar System, at 8.6 light-years. Although stars seem fixed in our sky, they are actually traveling in different directions and speeds. Sirius is one of these. In sixty thousand years, it will approach to 7.8 light-years and increase its brightness marginally. Sirius is not a solitary star; it has a companion, appropriately nicknamed “The Pup.” Telescope makers, testing a new telescope, accidentally discovered “The Pup” in January 1862. This star closely orbits Sirius once every fifty years. Sirius B, as the companion is formally called, is much smaller and dimmer than the primary. The Pup is currently distancing itself from Sirius and can be seen with high powers in medium to large amateur telescopes, once Sirius’ glare is blocked.

Skywatch Line for Monday and Tuesday, February 22nd and 23rd, 2016

This is the Skywatch Line for Monday and Tuesday, February 22nd and 23rd.

The Sun sets at 5:35 PM; night falls at 7:08. Dawn begins at 5:07 AM and ends with sunrise at 6:41.

The twilight sky contains only Uranus and the Moon. The Full Moon rises ten minutes after sunset. Native Americans of the Northeast had names for the Moons of different seasons. This Full Moon was called the “Snow Moon,” since the usually deep snow hampered hunters. Some tribes called it the “Hunger Moon,” also because it impeded hunters trying to find food for their tribe. The Moon sets at 7 AM Tuesday, and 7:30 AM on Wednesday. Monday night, the Moon hovers beneath Leo’s belly. Tuesday finds it two degrees away from Jupiter near Leo’s hind leg.

Uranus can be found at nightfall in Pisces. It appears as a sixth magnitude dot in our telescopes. It requires finder charts from astronomical magazines, websites and apps and sets by 9:45 PM.

Jupiter rises after the Full Moon. Jupiter is one of the few objects that resist the lunar glare. While binocular users can see the planet and its Galilean moons, telescopic observers can see weather bands on Jupiter and the Great Red Spot, a giant storm. The Great Red spot can be seen at 9:34 PM on Monday, and at 3:21 AM on Wednesday. They can also see the moon Ganymede cast its shadow on Jupiter at 2:56 AM Wednesday, followed by the moon itself at 4:17 AM. Jupiter is best seen at 1:11 AM and sets at 7:32 AM.

After Midnight, Mars rises at 12:23 AM. Zero magnitude Mars still inhabits Libra. It should be an obvious red dot amid the dim constellation. Saturn rises at 2:02 AM in Ophiuchus. Its cream color should distinguish it from surrounding stars, and its eight degree separation from Antares, the bright red star in Scorpius, helps find it. Venus, rises at 5:35 AM, blazes at minus 4 magnitude and occupies Capricornus. In telescopes, it appears about 90 percent illuminated. Mercury is last, rising at 5:55 AM. It is only two degrees above the horizon. A sky watcher should use brilliant Venus as a start, and look five degrees below to find the minus 0.4 magnitude planet. An unobstructed horizon assists in finding both Venus and Mercury.

After sunset, the giant constellation Orion appears. Canis Major, the Big Dog, follows at Orion’s heels. Sirius, the Dog Star and its brightest star, is the seventh closest star to our Solar System, at 8.6 light-years. Although stars seem fixed in our sky, they are actually traveling in different directions and speeds. Sirius is one of these. In sixty thousand years, it will approach to 7.8 light-years and increase its brightness marginally. Sirius is not a solitary star; it has a companion, appropriately nicknamed “The Pup.” Telescope makers, testing a new telescope, accidentally discovered “The Pup” in January 1862. This star closely orbits Sirius once every fifty years. Sirius B, as the companion is formally called, is much smaller and dimmer than the primary. The Pup is currently distancing itself from Sirius and can be seen with high powers in medium to large amateur telescopes, once Sirius’ glare is blocked.

Skywatch Line for Wednesday, February 17th and Thursday, February 18th , 2016

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

The 76% illuminated, waxing gibbous Moon rises at 12:53 p.m. Wednesday. As the sky darkens, and the constellations appear, you’ll notice that the Moon is at the top of Orion, and directly below open star clusters NGC 2175, NGC 2129, IC 2157, NGC 2158, and M35. Wednesday is the birth date of German astronomer Johann Tobius Mayer. Born in 1723, Mayer’s development of accurate lunar tables, enabled navigators to determine longitude more precisely than ever before. Latitude could be determined by finding the altitude of the Sun at noon, or the North Star’s altitude at night, but in the 1700’s and before, calculating longitude was a challenge. Mayer’s tables made it possible to use the Moon’s apparent motion relative to the stars to calculate Greenwich Mean Time. Once Greenwich Mean Time was known, longitude could be calculated by converting one hour of time difference to 15 degrees of longitude. Mayer’s method was accurate to within a half degree of longitude. The Moon sets at 3:45 a.m. Thursday.

There will be an extremely bright International Space Station pass over our region beginning at 6:58 p.m. Wednesday evening. Look to the west-northwest horizon to see the ISS rise past the Great Square of Pegusus, and higher close to the Andromeda Galaxy. At its zenith, the ISS will fly over the Pleiades star cluster and Aldebaran, before continuing on past Betelguese in Orion, before ending its long, bright trek over the southeast horizon.

February 17th is also the anniversary of the launch of the NEAR spacecraft from Cape Canaveral on a Delta-2 rocket. Renamed NEAR Shoemaker in March 2000, to honor Dr. Eugene Shoemaker, the legendary geologist whose research increased our knowledge of how comets and asteroids shaped the planets. The main objectives of the NEAR mission were to land on the first asteroid ever discovered, 433 Eros, and study the physical geology, composition and geophysics of the asteroid. NEAR also sought to clarify the relationship between asteroids, comets and meteorites. NEAR touched down on the asteroid Eros and began to transmit data from the surface on February 12, 2001, becoming the first spacecraft to land on an asteroid.

While the Moon is setting, Mars and Saturn will be rising over the eastern horizon, separated by 22 degrees. Venus and Mercury rise after 5:30 a.m. Thursday, 4.3 degrees apart, but very low on the horizon before disappearing into the glow of sunrise.