Re: AW: [APML] Exposure times with IDAS filter

["Marco Lorenzi" <lorenzi@libero.it>]

Hi Ulrich, I've been there twice and a friend of mine three times. The sky
is gorgeous and I believe it is darker that mag. 6.0, perhaps closer to 7.0
but I had never made a measure so I can't confirm it. Matt is right when he
says there are some problems due to Sahara dust but this is true only in
summertime and for low declinations. If you look at my site you'll find most
of the picture are made at La Palma island (close to Tenerife). If you can
go there, not in Tenerife because the sky in La palma is darker and because
of a special law the ligh polluttion is kept under control. For what
concerning the exposure time as far as I can say you can double the square
of your f/ratio with no problem. I see no utility to use idas filter,
perhaps you can increase contrast a bit but... Mah, I doubt you will have
any problem due tu light pollution ;-)
Ciao
Marco

----- Original Message -----
From: "Ulrich Beinert" <analemma@gmx.de>
To: <astro-photo@seds.org>
Sent: Sunday, January 06, 2002 3:54 PM
Subject: AW: AW: [APML] Exposure times with IDAS filter


> Thanks, that sounds good enough. It seems that if there are low clouds
over
> the population centers, the sky can get quite a bit darker, but it's my
> first trip there, so I only know what I've heard. Has anyone else on this
> list been to Tenerife for AP (or otherwise)?
>
> 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 15:53
> An: astro-photo@seds.org
> Betreff: Re: AW: [APML] Exposure times with IDAS filter
>
> I was there to provide software consulting for Gran Telescopio Canarias.
> They took me up to their mountaintop observatory and we did some visual
> through a 0.5m scope. I had not started doing AP then. There is a sizable
> population there that creates some light pollution. I would guess the
skies
> at mag 6.0.
>
> Matt
> --
> Matt BenDaniel
> http://starmatt.com
>
>
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