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The Sky This Week, 2019 May 7 - 14

Reflections on the Moon
First Quarter Moon, 2016 March 16
First Quarter Moon, 2016 March 16
imaged with an Explore Scientific AR102 102mm (4-inch) f/6.5 refractor
and a Canon EOS Rebel T2i DSLR from Alexandria, Virginia.

The Moon waxes through her crescent phases as she glides through the constellations of late winter and spring.  First Quarter occurs on the 11th at 9:12 pm Eastern Daylight Time.  Watch Luna pass in front of the binocular star cluster Messier 44 on the evening of the 10th.  The cluster, popularly known as “The Beehive”, can be seen as a hazy patch of light with the unaided eye from dark-sky locations and was known to the ancient Greeks and Romans.  It was one of the first objects observed by Galileo with his telescope, and to his delight it resolved into about 40 stars.  Today we know that the cluster contains over 1000 stars and lies about 575 light-years from the solar system.  As the Moon drifts in front of the cluster you can get a good sense of Luna’s motion through the sky as stars instantly wink out behind Luna’s dark limb.  Use binoculars or a small telescope for the best view of this interesting event.  

This is another great week to explore the Moon with a telescope.  You don’t need a large “light bucket” for this; some of my favorite views of our only natural satellite are with my 4-inch aperture refractor.  I find that lately looking at the Moon has taken on a more significant meaning to me as we come up on the 50th anniversary of the first landing by humans on another celestial body.  I was in high school during the early days of the Apollo program, and each time a flight departed for the Moon I was out with my telescope to familiarize myself with prominent lunar landmarks.  Today I still find time to look over those familiar landscapes, and I can still hear the echoes of the scratchy radio transmissions from the Apollo crews as they encountered this first alien world up close.  Overall the Moon has changed very little from the time of Galileo’s first views of its battered surface, but in many ways it is now profoundly different.  While we cannot see them, the artifacts of human exploration now dot dozens of places on Luna’s arid surface, and hundreds of kilograms of lunar rocks and soil now reside on Earth.  For your exploration, I highly recommend getting a good lunar atlas.  There are many available online and in book form, and they will be of immense help identifying particularly interesting formations.  Just about every feature visible in a small telescope has a name, and learning the stories behind those names is a fascinating study in itself.  

May 11th is national Astronomy Day sponsored by the Astronomical League, the “umbrella” organization that supports hundreds of local astronomy clubs around the country.  The League’s website is the place to go if you’re interested in events in your area.  Here in the Washington, DC area the Northern Virginia Astronomy Club will host events at C.M. Crockett Park in Midland, Fauquier County, Virginia from 3:00 pm until 11:00 pm EDT.  Bring your binoculars, telescopes, or just yourself for an afternoon and evening of activities highlighting the fun of amateur astronomy.  Weather permitting there will be opportunities to safely observe the Sun, and after dark the Moon and sundry deep-sky objects will be available for viewing through members’ telescopes.  Even if it’s cloudy there will be talks and demonstrations throughout the program.

You can still find Mars in the early evening sky as the red planet wends his way eastward among the stars.  He starts the week between the stars that mark the “horns” of Taurus, the Bull and works his way toward the “foot” of the Gemini twin Castor.  Mars is now beginning to lose ground to the relentless Sun.  He currently sets just over an hour after the end of evening twilight, but by the end of the month he goes below the horizon as the last rays of sunlight fade to darkness.

Jupiter now rises before 11:00 pm, so if you’re up in the late evening you’ll see him glimmering over the southeast horizon.  You’ll still need to wait until the wee hours for your best view of him.  He’ll be high in the southwest as morning twilight breaks. 

Saturn crosses the meridian shortly after 5:00 am, when he will be about 30 degrees high in the southern sky.  This will be your best time to examine him in the telescope, but the reward for such early activity will be a fine view of the planet nestled in his wide-open rings.

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