Monday, June 12, 2006

Full Moon on the Urban Sky

Session name: 20060610.2100

Near the end of our observing session, Charlie and I paused to observe the moon and assess its impact on the background sky. Notwithstanding a near full Moon the sky appears equally dark all around the celestial dome covering Central Park. In fact we were able to see down to mag 5.0 in Ursa Minor (eta- & theta UMi and Pherkad Minor, stars of the Little Dipper's bowl).

Conveniently Antares was 3 and half degrees, 2 o'clock from Moon - in celestial terms that's NW. The halo surrounding Moon aaused by its brilliance extended about two-thirds of the way to Antares. Beyond the halo the background sky near Antares appeared equally dark as the sky near zenith or, turning around to the north, in "The Corridor". Our NYC skies are not impacted as much by a full Moon as one may think.

In order to see features on Moon squinting and l'il averted visio helped. I could see each mare and Tycho clearly on the lunar orb.

It got me thinking about a few weeks back when I was in NJ for a dinner event. After stepping outside I looked up to a "black" sky. I mean black, a term I wouldn't assign to describe the NYC sky. To my surprise the NELM was not great somewhere in the mag 3 range. I can now appreciate those suburban astronomers when they say they can only see down to mag 2 or 3. From TotL more stars are visible which I attribute to the darkness of our immediate observing area.