(meteorobs) Obs: 20 October 2007

[David Oesper]

Hi Wayne,

Thanks for your note.  Yes, I need to "graduate" to being able to
quickly do star count regions.  For now, I thought at least I should
provide a series of Sky Quality Meter (SQM) measurements at the zenith
before and after an observing session.  The SQM (available from
Unihedron) has about an 80 degree field of view.  I probably should
make a series of measurements at around altitude 45 degrees in the
direction I am looking, but with such a wide field of view horizon
obstructions can be a problem. Another concern is my inability to
repeatedly point the SQM at altitude 45 degrees whilst lying prone in
a lawn chair.  Pointing at the zenith is a little easier to do.

The following equation seems to yield reasonable results for my
unaided eye limiting magnitude when using the Sky Quality Meter:

Limiting Magnitude = [(SQM-8.89)/2] + 0.04

So, for the 20 Oct 2007 UT observations, the visual limiting magnitude
was about 6.3.

Best Regards,

Dave

--- In meteorobs at yahoogroups.com, meteoreye at ... wrote:
>
> Any idea of how to convert your "Zenithal Sky Brightness: 21.37
mag./sq. " into LM so it can be used for ZHR calculations?