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[vsnet-survey 70] (fwd) Re: (fwd) Finding the right focal lenght for Novae Search
From: aah@nofs.navy.mil
Date: Wed, 12 Dec 2001 09:25:18 -0700
Subject: [vsnet-chat 4939] Re: (fwd) Finding the right focal lenght for Novae Search
Cristovao Jacques wrote, regarding Nova searching:
>Increasing the focal length we gain in
>magnitude but we loose in field coverage, so what will be the best FL.
>Do you also recomend any kind of filter?
I would worry a bit about source confusion at 10th magnitude
in the heart of the Milky Way with 70arcsec pixels. You may not
be able to uniquely identify novae until they get quite a bit
brighter. There is always a tradeoff between depth and field
coverage, and how you choose depends on how bright you think a
typical nova will be when you can detect it. Perhaps some
research into the nova discoveries over the past decade would help.
If you want to use a filter, I'd recommend R. It matches the
peak response of the CCD and also includes Halpha, a very strong
emission line in most novae. However, many telephoto lenses will
have to be refocussed once you get into the red.
Arne
vsnet-adm@kusastro.kyoto-u.ac.jp