Measuring your own sky quality

[Dipper]

Is there a way to measure the sky quality of your observing site without any specialist instruments? I was looking at one of those "Sky Quality Meter" gadgets and thought if there is a simple method of perhaps using a DSLR to determine how dark or how light-poluted the sky is?

[pete_l]

Have a look at Samir's page here. Also check some of his other work, there's a lot to be learned there.

[L8-Nite]

I gage the sky, based on memories of past experience, of the places I've traveled.

Edit: Sorry, this topic seems to be for Imagers, I am visual only.

[Capricorn]

Two I have seen is:

How many stars can you see in the great square of Pegasus, and,

Similar for a rectangle created in Orion, think it was the 4 stars that make the shoulders and the feet = Betelgeuese, Bellatrix, Rigel and Saiph.

Only catch is I don't know what number implies good or bad.

One of these was used a couple of years back by a body such as BAA, maybe out of Star Gazing Live, as data. I recall being asked to have a go.

[James]

How many stars can you see in the great square of Pegasus, and,

This one is good: http://freestarcharts.com/index.php/stars/17-guides/stars/17

James

[Dipper]

Well Pegasus and Orion aren't a very good example as I can clearly see all main stars of Orion, including the six "bow" stars (π1 - π6) and all the "antenna" stars (χ 1-2, υ, ε and μ). I'd rather be interested in using captured image to measure "magnitude per square arc second" - at least this is the description of what that gadget does.

[DrRobin]

I used Samir's method to get a value of just over 5. I then checked it with a dark sky map and an estimate from the Bortle scale, they were all somewhere near.

If you want to compare your site to some other persons site that you don't visit then without a meter it is always going to be subjective. If you want to compare your home to say a dark site, just use the same method at both, it will at least be relative even if it isn't absolute.

[SteveNickolls]

Hi,

I have used the magnitudes of stars in Ursa Minor to judge the local sky by eye here to good effect. Observing close to Nottingham the limiting sky value is a poor but quite accurately estimated as being 4.3. You should be able, sky depending, to go as far as 6.4 so Magnitude 5 will be well in the scale of visible stars.

Cheers,

Steve

[callump]

There was an article about measuring skyglow with digital cameras in Sky & Telescope a few years back (April 2006).

You can actually download the article from Sky&Tel, and its linked from the following page:

http://www.skyandtelescope.com/community/skyblog/observingblog/116148384.html

Callum