Wednesday, May 09, 2007

2007 May 19 - Int'l Sidewalk Astronomy Night

I plan to be at the southeast corner of the Great Lawn, Central Park setup by 8pm EDT. Later around 10:00pm, I'll move eastward towards Delacorte Theater, about 50 yards, for a better angle to observe Jupiter rising above the trees in our northeast..

Objects I intend to show will concentrate mostly on the Solar System and, if possible, will show a little diversity with Doubles, Open Clusters, and Globular Clusters.

Sunset occurs at 8:09pm EDT. I anticipate waning, gibbous Venus and waxing, crescent Moon to be the early showcase in the constellation Gemini, standing in the western sky. A 2° field of view eyepiece should capture both and also provide enough magnification to see Venus' phase. Naked eye I am sure it will be splendid sight. From the southeastern corner of the Great Lawn, Mercury will be visible at 15° altitude descending with Taurus. Mercury will appear as small round dot under high magnification, at 6" (arc seconds) in size, distinct from a stellar point. If one can visualize the size of the Jovian Moons, then Mercury will be slightly larger. Not much longer after sunset that Saturn pops from a twilight sky leading Leo's head. Regulus, alpha star of Leo, will be recognized to the left of Saturn, more easterly. Even at this hour and a magnification say 50x ~ 60x, everyone will see the rings and moons of Saturn. Higher magnification and increased contrast will provide greater size and more detail to the observer.

While waiting for Jupiter to rise, there may be time to offer some celestial diversity with open clusters like M35 in Gemini or M44 in Cancer. When Jupiter does rise the Great Red Spot will be near the center line of the planet and 3 moons will be visible. Europa, Ganymede, Callisto will be seen with Jupiter while Io will have to egress from two events: an occultation and followed by an eclipse.

A pretty double star that exhibits color is nearby iota Cancri (STF1268 magnitudes: 4.13/5.99), north-northeast of M44. Speaking of doubles, Polaris, alpha Ursa Majoris, is a fun object. First, to point out where our North Star can be found and which you may discover many do not know. With adequate magnification, Polaris will reveal its much fainter secondary star. Though no color, this pair exhibits a great range in magnitudes - 2.10/9.10 - with Polaris (WDS STF93). Lastly, there is Mizar & Alcor, a naked eye double in the tail of Ursa Major, or more familiar to pedestrians as the handle in The Big Dipper. Can you see the lost sister hiding naked eye? Then throw a scope at the pair to observe that Mizar has a come 14" ( seconds) separated. Compare that with Mizar at 12' (minutes). Sidus Ludovicianum will be spotted as a fainter star between Mizar & Alcor.

Staying with deep sky sky objects that are relatively bright, a couple of the bright Messier globular clusters are easy to find and may be suitable for the scope. M13 is easily found in the Keystone of Hercules and M3 in Canes Venatici is nearby and slightly fainter.

I expect all to have a good time with a good dose of fascination and good cheer. Typical for our sidewalk astronomy nights in Central Park.