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A neutral density or polarizer filter?

Started by kendo, 08/04/2009 10:56AM
Posted 08/04/2009 10:56AM Opening Post
The moon is way too bright for me in my 13" scope. This weekend I tried a friend's Lumicon ND 13%. That helped a lot, but I could still drop the light a bit. Looking on the Anacortes web site, I saw variable polarizing filters. So I wonder, should I get a couple of ND filters, or a variable polarizing filter to make the moon more comfortable to view?
Posted 08/04/2009 01:14PM #1
A variable polarizer is at least two sheets of glass and four surfaces. Going with the theory that less is best, I would choose a fixed ND filter if I had to use anything at all. 13% is not a whole lot of reduction. Keep in mind that you can always up the magnification to reduce the brightness. Doubling the power cuts the brightness by a factor of 4, way more than 13%.

(my 2 cents worth for free!)

dan
Posted 08/05/2009 08:06AM #2
Thanks, everyone for your help. I'll get the variable polarizer.

The advice of several of you to keep lights on made me laugh a bit. That makes complete sense, while going against everything else I'd expect for astronomy.
Posted 08/05/2009 10:20AM #3
You can also increase the manification to decrease the brightness, if you like to look at smaller features.

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