Phyllis K LangAuthor of Deep-Sky Planner/SQM Reader Prohttp://knightware.biz
Quote:.......Here are a few things you might consider in assessing your skies......
George N Obsession 20 Optical Guidance Systems 10" F/9 R-C Cass 6" F/5 & 8" F/8 home-made Newts Explore Scientific 127mm ED MI-250 mount Denk II bino-viewer, with PowerX and Newt reducer, Member, International Dark-Sky Association
Quote:I have the incredibly good fortune of living in the Magdalena Mountains in central NM. I've estimated that I live in the Bortle grey zone as I cannot see shadows cast by the Milky Way.
Quote:I picked up a SQM-L amd measured sky brightness at nautical twilight in the evening and morning, taking several readings and averaging. In the evening I was recording 21.50 mag/sq arcsec, and this morning, 21.90.
First and foremost observing love: naked eye.
Last but not least, telescopes.
And I sometimes dabble with cameras.
The night sky is the canvas....
My optics are the brush....
The Milky Way is the masterpiece
Turtles top to bottom....turtles all the way down
A Brief History of Time
Quote:I'm skeptical that you actually took these at the end of nautical twilight. I would expect the sky to be closer to 20.5 at that point. Are you sure you didn't mean astronomical twilight?
Quote:Because of the enormous variation in natural skyglow, I don't think the SQM can distinguish between the gray and black zones.
Quote:Thanks for the good read. I'm learning! Quote:I'm skeptical that you actually took these at the end of nautical twilight. I would expect the sky to be closer to 20.5 at that point. Are you sure you didn't mean astronomical twilight? I made my observations about 100 mins after sunset, and before sunrise, in early Jan.