I tried the Baader Moon & Skyglow filter early this morning to photograph comet C/2013 R1 Lovejoy with my Canon SX50 HS as I mentioned yesterday. It has some interesting effects to the photos.
It does tone down the white noise as intended, but the background turns from black to dark blue. The tail doesn't really become more bright because it's a filter that blocks certain wavelengths, not some sort of a booster. But due to slightly lower noise it's easier to make it more visible with post-processing.
For reference, the bottommost star in the cropped photo above is HR 4572 (HD 103799; HIP 58287), a 6.6 magnitude star in Ursa Major.
Settings: 243mm - ISO 1600 - 6s - f/5.6
Time: 2013-11-21 05:32 - 05:36 KST
Location: Suwon, Korea
15 photos stacked with RegiStax 22.214.171.124