Clouds, night vision. and light pollution - plus new binoculars

March 13, 2008 - T2S2 4:30 am DST

The Astro Physics 15X70 binoculars arrived, but i have little to report except: Boy, when the clouds roll in you really appreciate the light pollution around you. Not "appreciate" as in like - but "appreciate" as in evaluate.

I've noticed this before, of course, but what set me off this morning was I had become reasonably well dark adapted when it quickly became totally overcast - and yet I could still see everything around me - not in the sky, but on the observing deck and in the yard. It was shocking to realize not how much star light was getting through the clouds - none I would say - but how much artificial light was being reflected off the clouds and back to Earth to light up my surroundings.

In my case most of this was coming from a relatively small town center aboyt three miles to my northwest. If I looked to my south - where there are only residential homes between me and the ocean less than two miles away, the sky was dark. No stars - but the clouds were barely visible.

OK - the binoculars. They're the most rugged constructed pair of binoculars I've ever owned. They have individual focus eye pieces - which may or may not prove good. They bring in significantly more light than my 12X36 IS, though the overall improvement from a practical sense isn't that much. I tested this on the Coathanger which was in the clear for a short while - well, not in thick clouds, just some high haze.

With the 15X70s I could make out three stars that were magnitudes 8.6, 8.8 and 9.2 - with the 12X36IS I could just detect the brightest of these stars. (That's also an indicator of how poor the transparency was - these should have been easy in either binocular.) However, both instruments certainly captured the Coathanger experience which again raises a basic question about just how much optical aid you need to experience what i think is important. More and more I'm coming to the conclusion that a lot of the thrill of looking through a large instrument is simply psychological - especially for beginners.

Anyway - I also checked out M13 and M92 and Albireo - wasn't overwhelmed with any of this. Witht he 15X70s you MUST use a mount and this restricts flexibility. I have to be fair and do some galaxy hunting on a good night. Also, from an instruction point of view these might be betetr because I can point them at a target, then have someone else look. Also, with the finder that is onthe way it may make it significantly easier for visitors to find things on their own.

Bottom line - right now, I'm not overwhelmed, but I have to give them a better chance to prove themselves than I could this morning.