Quote:
Originally Posted by luka
The 2" Moonlite focuser leaks light where the drawtube enters the focuser body and also where the 2" tube enters the drawtube. Google indicates that this is common with most of focusers and that this is normally not of concern for nighttime imaging.
By the way, the easiest way to test for light tightness of the imaging train is to have dust on the sensor. Any light leak will be quite obvious 
The moral of the story is that focusers may not be light tight. Take darks in darkness with camera only, i.e. do not try to cut corners.
Hopefully my experience helps someone else with similar issues. |
Hi luka,
If you are concerned about the light leaks in the focuser or anywhere else, but still want the ease of leaving your system setup and want to continue with daytime Darks, you could use a blanket to cut out the extraneous light together with a lens cap.
Perhaps even an o-ring could be placed over the drawtube and slid up against the focuser housing when required to make it light-tight. If that doesn't slide as easily as you'd like then cut a washer from closed cell neoprene foam (wet suit material) or if suitable for the outer diameter of your drawtube, cut a 10-20mm slice from a cylindrical neoprene stubbie holder and use that like the o-ring.
Best
JA