RE: [APML] Sun filter: Venus transit

["Richard Klappal" <klappal@xnet.com>]

I've got both the Thousand Oaks and the Baader filter.  I find them about
equal in performance except that the 1000 Oaks gives a yellow sun and Baader
gives a white.  (THe old Tuthill gave a blue sun.)

It all depends on what you think "correct" is.  A photographic yellow filter
makes the Baader images look like 1000 Oaks  ;-)

Rich


-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of Radu Corlan
Sent: Wednesday, 04 February 2004 10:00
To: Discussion of Film Astrophotography
Subject: Re: [APML] Sun filter: Venus transit


On Wed, 4 Feb 2004, Pere Sanz Cases wrote:

>
> Hi all,
>
>   I'm considering purchasing a sun filter for imaging the Venus transit
> (June, 8th). I took some nice pictures of the '99 total solar eclipse
> with a 400mm lens by using a mylar sheet along with a Wratten
> twenty-something (I don't remember now ) filter which tinted the sun
> during the partial phases with a nice orange color.

For wideband, the Baader foils work great. It's very easy to make the
cells for the foils, and they produce very good images. You can get a
large sheet and share it with friends, or make filters for all your
instruments. They also have "photo" filters, which are more transparent
(so you can get short exposure times on long-focal length instruments).
But for visual use, you need a ND filter (like a moon filter or so) at the
eyepiece, or the image is too bright.

Radu

>   Now I want to take pictures at prime focus and am wondering what kind
> of filter - affordable, don't say H-alfa - should be best suited for
> imaging this event.
>
>   I wonder what are the most important moments of the transit to
> photography. I know that there are not experienced photographers of such
> phenomena, as long as there is no one alive now who has experienced  a
> venus transit :-), but maybe someone could explain what could we expect
> to be the big moments of the transit (black-dot, or something...)
>
> Cheers,
>
> Pere Sanz
>
>
>
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>

--

-------------
Radu Corlan       Snail Mail: Bucuresti sect. 1,
rcorlan@pcnet.ro  str. Argentina nr. 28, Romania

   You can still escape the "Gates" of Hell!
                 Use Linux!


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