Unihedron Sky Quality Meter SQM, hand-held meter for the darkness of the night sky

Is it really darker tonight than last week, or does it just seem that way? With a sky quality meter, you turn the handheld meter up and press the button to read the brightness of the night sky in magnitude per square arcsecond. The higher the number, the darker the sky.

This is how you compare areas of interest, track the impact of light pollution, and see how your own garden performs year-round. Handy if you want to know where you stand. the Milky Way can be best viewed.

Always measure the same way: with the meter straight up, away from lights, and take a few measurements in succession for a reliable value. Also note the position of the moon, which you can find in the The lunar calendar If you find it again, then you can honestly compare the evenings later on.

If you want to measure more precisely, with less influence from lights or trees at the edge, then there is the SQM-L with lens.