RE: [APML] M42 is bac

[Alen Koebel <alen_koebel@yahoo.ca>]

MV is not effective as an LPR. The best LPR
is probably the IDAS (48mm is $189). I have 
not used one myself, but I will eventually 
get one to replace my Deepsky filter.

http://www.sciencecenter.net/hutech/idas/lps.htm

-----Original Message-----
From: Grant [mailto:GB1029@inter-linc.net]
Sent: Friday, November 15, 2002 8:34 PM
To: astro-photo@seds.org
Subject: Re: [APML] M42 is back!


Roland,
Thanks for the advice.  Would you say this applies
to tp work with the traveler as well?  No need for an
Mv?

This is an unfortunate consequence because I routinely
use an lps under my mag 5.5 skies.  Although the
improvement
is modest, I do get a touch deeper. I guess I could
always buy a 105mm lps...

Grant

At 07:50 PM 11/15/02 -0500, you wrote:

Take the filter out. They will produce those nice
halos around bright stars because the plane-parallel
surfaces reflect light back and forth and produce an
out-of focus ghost image. Most filters are not
properly multi-coated and will reflect quite a bit of
light. The added optical path of one reflection
between front and back surface will give you the faint
out-of-focus image.

Roland Christen 

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