Re: [APML] Orion skyglow filter

["John Boudreau" <jeboud@mediaone.net>]

Hi Grant,

I think you would have been better off with the 48mm version of this filter.
I don't have a CEG (I do use a GEG), but with a rear cell SCT mounted
filter, doesn't the CEG goes on after the filter? Now both the camera and
prism/off-axis tube will receive filtered light, and your guide stars will
be fainter (= to harder to find) for both manual and autoguiding. I believe
the CEG accepts 48mm filters after the reducer. If that's the case, with the
48mm screw-in filter, you could mount it after the prism/off-axis tube, thus
keeping your guide stars bright. You may also end up with additional
vignetting with the SCT rear cell version also.

Ever shoot with one these filters before? Unless you plan to shoot B&W only,
get ready for some HEAVY shifting in color, _well_ into the magenta range,
and any blues will be killed (been there years ago). Currently, the only
filter that works for color astro work is the IDAS LPS filter sold by
Hutech. And it works quite well too, virtually no color shift.
http://sciencecenter.net/hutech/tokai/lps.htm

 I don't know of anybody who was happy shooting color with an Orion Skyglow.
Or Lumicon's version either. But years ago they were the only game in town
so they had their place back then.

However, both the Orion and Lumicon filters are better than the IDAS for
visual use.

John Boudreau
jeboud@mediaone.net
http://people.ne.mediaone.net/jeboud/astro.htm
----- Original Message -----
From: "Grant" <GB1029@inter-linc.net>
To: <astro-photo@seds.org>
Sent: Saturday, November 03, 2001 2:33 PM
Subject: [APML] Orion skyglow filter


>
> I just received my new skyglow filter for my Sct
> (rear cell version).  I was wondering how well this
> will work out photographically.  Specifically, in front
> of my ceg focal reducer?  Will having the reducer positioned
> after the filter affect anything?
>
> Grant
>
>
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