thanks for the tips, and the cool picture. stupid question... what's a "standard ND filter"? and what else would you use and what would be the difference? i'm planning to use it on an 8" dob with a non-modified Canon Rebel XS On Sat, Sep 3, 2011 at 7:40 PM, Jared Smith <jared@smithplanet.com> wrote:
On Sat, Sep 3, 2011 at 3:09 PM, Chrismo <djchrismo@gmail.com> wrote:
Just curious, since I don't know much about this end of things... would this film be "as good" as more expensive glass filters?
I think the Baader film is just as good as the glass filters, so long as you are looking for a standard ND filter. And it's much less expensive. I've always purchased mine at http://astrozap.com/scripts/prodList.asp?idCategory=31 and made home-made filter cells precisely as Rodger described.
A few lessons learned:
- The photographic filter (ND=3.8) is NOT safe for visual observing, even with eyepiece filters - not just because it's quite bright, but because it lets through way too much UV. I learned this the hard way - thankfully my eyes weren't permanently damaged.
- For larger scopes (maybe > 6"), use either the visual filter material (ND=5) or use a smaller, off-set photographic filter. I did a full aperture photographic filter on my 8" Newtonian and even at 1/4000th second at ISO100, my exposure are slightly overexposed.
Here's a photo I took some months back - http://smithplanet.com/astro/solarsystem/solar/5-2011/final.jpg Note that this is false coloring.
Jared
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