Skywatch Line for Wednesday, September 14th and Thursday, September 15th 2016

This is the Dudley Observatory Skywatch Line for Wednesday, September 14th and Thursday, September 15th written by Louis Suarato.

The 95% illuminated, waxing gibbous Moon rises at 5:57 p.m. in the constellation Aquarius Wednesday. As the sky darkens, you’ll be able to locate the globular cluster, M2, about ten degrees above the Moon. Discovered in 1746 by Jean-Dominique Maraldi, M2, at 175 light-years in diameter, is one of the largest known globular clusters, and contains 150,000 stars. M2 is 37,500 light-years from Earth, and is estimated to be about 13 billion years old, making it one of the oldest globular clusters in the Milky Way Galaxy. M2 can be seen with the naked eye under optimal conditions, but better viewed through binoculars or a small telescope. Larger telescopes will resolve individual stars within this cluster.

Mars and Saturn are now separated by 13 degrees, and can be found over the south-southeastern horizon between the constellations Scorpius and Ophiuchus. If you look 20 degrees above Saturn, you’ll find globular cluster M10 in Ophiuchus. Look four degrees to the right of M10 for globular cluster M12. Both globular clusters were discovered by Charles Messier in 1764, M10 on May 29th, and M12 on May 30th. Ophiuchus is also the home of the Summer Beehive open star cluster. Look about 15 degrees above M10 for this open cluster. The Summer Beehive, or IC 4665, is a large cluster that can be viewed through binoculars.

The nearly Full Moon rises at 6:34 p.m., Thursday, a half hour before sunset. Use the Moon on this night to find Neptune. Look for Neptune 2 degrees to the right of the Moon. At an average distance of 30.1 astronomical units, Neptune is the eighth, and farthest known planet from the Sun. One astronomical unit is equal to 93 million miles. Neptune is not visible to the naked eye, so, use binoculars or a telescope to view this planet.

The Albany Area Amateur Astronomers invite you to join them for their monthly meeting this Thursday beginning at 7:30 at miSci in Schenectady. This month’s speaker is Albany Physicist Dr. Vivek Jain. Dr. Jain is part of the team that manages the ATLAS instrument, one of two general-purpose detectors at CERN, the European Organization for Nuclear Research. Dr. Jain will be discussing the link between particle physics and Cosmology. The directions to miSci can be found at

Skywatch Line for Friday, October 9, through Sunday, October 11

This is Dudley Observatory’s Skywatch Line for Friday, October 9, through Sunday, October 11, written by Alan French.

The Moon was at last quarter this past Sunday and is now moving toward new, so a waning crescent Moon rises during the early morning hours.

Saturday morning’s sky will feature a lovely grouping of Venus, Mars, Jupiter, and the old, crescent Moon. Look toward the east at 6:00 am. Brilliant Venus will be highest, with bright Jupiter lower and a bit to its left. Between the pair is fainter, reddish Mars. A lovely Moon will be below this trio. If you have a good view to the east and the horizon is free of haze and clouds, look for Mercury, below and a little left of the Moon, and just three degrees above the horizon.

By Sunday morning the Moon will be a bit lower than Mercury and a little to the planet’s left – requiring clear skies down to the horizon and a good view east.

The Albany Area Amateur Astronomers will take advantage of the dark moonless skies this weekend to hold public star parties at Landis Arboretum in Esperance. The star parties will be at 8:00 pm on Friday, October 9, and Saturday, October 10. At star parties club members set up telescopes to show guests a variety of celestial sights – galaxies, nebulae, star clusters, and double stars. All ages are welcome and there is no admission charge, although we encourage guests to make a modest donation to our fine hosts, Landis Arboretum.

Landis Arboretum is on Lape Road and there are good signs leading there starting at Route 20 and Charleston Street. Turn up Charleston and follow the signs (when driving into Esperance on Route 20 from the east Charleston is the first right after crossing the Schoharie Creek). You can also find directions on their web site. After reaching the farmhouse on the right and parking lot on the left continue up Lape Road for 100 yards. Turn right into the the Meeting House field driveway. It will usually be marked with a “Star Party” sign.

For newcomers there will be a brief introductory talk at 8:30 pm. Gather in the south side of the gravel parking area next to the Meeting House. The talk will include hints about using and enjoying the telescopes and a brief tour of the brighter constellations.

Star parties are canceled if the skies are mostly cloudy or if it’s raining. If in doubt, please call 374-8460 to insure the event is being held. If no one answers the phone, wait for a message.


Skywatch Line for Friday, October 2, through Sunday, October 4

This is Dudley Observatory’s Skywatch Line for Friday, October 2, through Sunday, October 4, written by Alan French.

The Moon reaches last quarter on Sunday afternoon, so a waning gibbous Moon rises late in the evening on Friday and Saturday, and it will be a waning crescent when it rises Sunday night. The Moon rises at 10:10 pm Friday, 11:02 pm Saturday, and 11:57 pm Sunday.

In the early evening the Milky Way, that hazy band that is the combined light of many distant stars in the plane of our galaxy, stretches high across the sky. It may be invisible to people in or near the city, where the lights brighten the sky, but it is a lovely sight from the dark skies away from town. Around 8 pm it stretches roughly from the south southwest to the north northeast. It is brightest and broadest in the south, a beautiful sight as it passes overhead through Cygnus, the Swan, and its luster diminishes as it reaches the distinctive “W” star pattern of Cassiopeia, the Queen, high toward the northeast.

Dark skies are not the only requirement for your best views of the Milky Way – your eyes should also be thoroughly adapted to the dark. You’ve certainly noticed that your eyes gradually get used to the dark, allowing you to see better with time. There are two changes. The pupil opens wider within seconds, allowing more light into the eye. There is also a chemical change which greatly increases your eye’s sensitivity. The full transformation takes 30 to 40 minutes.

White light ruins your dark adaptation and the process has to start again. To preserve their night vision amateur astronomers use dim red lights, which allow reading star charts and notes without ruining one’s night vision. Red plastic or construction paper can easily turn a regular flashlight into an astronomer’s flashlight – but remember it should be just bright enough to read charts when you are completely used to the dark.

A reclining lawn chair is ideal for exploring the Milky Way, and there is even more to see with binoculars.

We often recommend observing the Moon with binoculars or a telescope when it is near first quarter. It is a similarly great target near last quarter – but the timing is not convenient for most people. If you’re an early riser the Moon, just past last quarter, will be high in the southern sky at 6:00 am Monday morning. When the Moon is high in the sky the views tend to be steadier and detail better seen. Monday morning the sunset line or terminator is near the center of the Moon’s disk, ideally placed for viewing. Along the terminator shadows are long and details stands out in bold relief.

If you took advantage of National Observe the Moon Night last Saturday, just before first quarter, you probably noticed the Moon was not very high in the sky then.

Skywatch Line for Friday, September 25, through Sunday, September 27

This is Dudley Observatory’s Skywatch Line for Friday, September 25, through Sunday, September 27, written by Alan French.

This is an exciting weekend for amateur astronomers and casual sky watchers – we have a total lunar eclipse on Sunday night. The eclipse is well timed for the eastern United States, with the eclipse visible from start to finish.

When the Moon is full it is on the opposite side of our Earth from the Sun. Earth casts a shadow into space, and usually the Moon passes above or below the shadow and we simply enjoy a lovely full Moon. When the Moon moves through the shadow, we have a lunar eclipse. On Sunday night the Moon will move completely into the darkest part of the shadow, so we’ll have a total lunar eclipse.

The Earth’s shadow is composed of two parts. The lighter, outer penumbra is where Earth only blocks part of the Sun’s light. The darker, inner umbra Is where the Earth blocks all of the Sun’s direct light. Light, however, is bent or refracted as it travels through our atmosphere. It is also scattered, with the blue end of the spectrum scattered the most. The result is that the light bent into the darker part of our planet’s shadow is mostly red, so a totally eclipsed Moon may appear reddish. How colorful and how bright the eclipsed Moon appears depends on how many clouds are around the edge of the Earth, as seen from the Moon, and how many particulates are in our atmosphere. (Forest fires, volcanoes, and man-made pollution can darken an eclipse.) The Moon is illuminated by the sunrises and sunsets around the Earth.

The Moon will enter the penumbra, the brighter part of the shadow, at 8:12 pm, but it will be some time before the subtle penumbral shading will be visible on the Moon. You might spot it around 8:40 pm.

The Moon will move into the umbra at 9:07 pm and this darkening will be almost immediately obvious. By 10:11 pm the lunar orb will be entirely in the umbra and the eclipse will be total. The Moon will be in the southeast. The Moon will be deepest into the umbra at 10:47 pm and will start leaving the umbra at 11:23 pm, ending totality. It will slip completely out of the umbra at 12:27 am Monday morning, and the last subtle penumbral shading will be visible around 12:55 am. At 1:23 am the Moon will be completely out of the penumbra and the eclipse will be over.

As the Moon moves fully into and through the umbra look for color, perhaps red or copper. Also notice the darkness of the eclipsed Moon. The northern part of the Moon is deeper into the umbra, so it will probably look darker.

No special equipment is needed to watch and eclipse. It is lovely by eye. It can be interesting to watch with any modest optical aid too – binoculars or a small, lower power telescope.

If you’d like to join other people and have telescopic views of the eclipse, consider going to miSci for Dudley Observatory’s Night Sky Adventure: Total Lunar Eclipse. There is a modest admission charge.