AW: [APML] Exposure times with IDAS filter

["Ulrich Beinert" <analemma@gmx.de>]

Matt,

thanks for the tips. Even if the skies are not 7m, they'll be way better
than anything I've ever had in my life. Europe is a really unfortunate place
to be if you're an astrophotographer (or doing any form of astronomy for
that matter). It's just too crowded here! :-)

When you were on Tenerife, were you up on the mountain? How good were the
skies? Do you have any pictures from when you were there? There are some on
this website: http://aida.astroinfo.org/levens/

Ulrich

-----Ursprüngliche Nachricht-----
Von: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]Im
Auftrag von Matt BenDaniel
Gesendet: Sonntag, 6. Januar 2002 15:29
An: astro-photo@seds.org
Betreff: Re: [APML] Exposure times with IDAS filter


Ulrich,

I've been to Tenerife and the skies are definitely not as dark as mag 7.0.
One possible problem they have is sometimes they get fine Saharan dust in
the air, which can ruin the transparency. I would say don't use the filter
if the transparency is good. Also, I would only use the filter for emission
nebulae. The rule of thumb I use is 1.5x exposure time with the filter.

Matt

At 11:35 AM 1/6/2002 +0100, Ulrich Beinert wrote:
>When using my IDAS filter from my "dark-sky" site, which has a lim. mag. of
>about 5.5, I can expose twice as long when using the IDAS filter in order
to
>get the same background brightness.
>
>In April, I'll be flying to Tenerifa, where the sky will be *very* dark at
>2200m altitude. Still, I'm thinking of using the filter anyway, because
>there will always be *some* light pollution, and I've heard that using the
>filter at 6.5-7m sites makes sense too. Can I also double the exposure at
>such a dark site, or would that cause the background to get too bright?
>
>Ulrich

--
Matt BenDaniel
http://starmatt.com


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