July 16, 2007 - Description of observing conditions at Anderson Mesa courtesy of Brian Skiff

Apart from a rather modest amount of light from Flagstaff, it is what I would term a "true dark" site. I've had many folks say they simply didn't believe the sky could look as it does, and also folks have noted that _Mars_Hill_ (the original Lowell Obseratory site just a few blocks west of downtown Flagstaff) is about as dark as their "dark" site Back East. The overall appearance of the sky is very similar to McDonald, Las Campanas, etc. I have seen down to V mag 7.8 visually, and seen M81 naked-eye (twice). Per the various descriptions in the "how dark is it?" article, which Dan has already copied onto the Kalmbach web site, many other night-sky features most folks have not seen are readily visible there. There are large regions of the Southwest US with essentially identical sky quality.

My telescopic magnitude limits on stars are about V=14.0 with my 70mm Pronto, and about 15.5 or so with my 15cm refractor. Saw Pluto a few years ago (V=13.8), and 3C 273 (about 13.0) with the Pronto. People have been skeptical about seeing this faint, particularly with with the Pronto, even though the values quoted above scale directly with aperture. See for instance: http://mira.aavso.org/pipermail/aavso-discussion/2004-October/011001.html ...in regard the NGC 6946 supernova from that time, and succeeding responses about being able to go only to 11th with a 4-inch.

Typical seeing is 1".2 as measured by image-motion. Plenty of nights with subarcsec seeing when observing in the open air (i.e. not in domes, where the seeing is almost always much less good).

SQM data for Anderson Mesa can be found here:
http://www.lowell.edu/Research/cloudiness_data/clouds.html

Typical night is about muV = 21.5 per the SQM readings, dependent mainly on sidereal time (a couple tenths brighter with Milky Way overhead, a couple tenths darker when the galactic pole is overhead). Darker also after midnight as the lights of Flagstaff (mainly car headlights!) are reduced. See the June 2007 clouds/SQM dataset for a typical run of nights where it gets brighter toward morning simply from the summer Milky Way rising. Notice the very high night-to-night consistency of the data compared to many of the values posted at the Unihedron Web site from customers.

If you go out to the Morman Lake overlook or farther toward Happy Jack, it is about 0.2 mag darker per SQM readings. The sky looks somewhat better visually, but the difference is not large. Somewhere between Mormon Lake and Happy Jack is the light-pollution minimum between Flagstaff and Phoenix.