Re: [APML] OT: Penumbral eclipse

["Stan Richard" <stanrichard@hotmail.com>]

Taras, thanks, you're right, I should have stated equivalent focal length.



Stan Richard
Events in the Night Sky
www.nightskyevents.com




----Original Message Follows----
From: Taras R.Hnatyshyn <tarashnat@earthlink.net>
Reply-To: Discussion of Film Astrophotography <astro-photo@seds.org>
To: Discussion of Film Astrophotography <astro-photo@seds.org>
Subject: Re: [APML] OT: Penumbral eclipse
Date: Sun, 24 Apr 2005 12:09:51 -0400

Stan,

The focal length doesn't change if you crop a photo, it was still taken with 
the same lens, so it doesn't change if you use a smaller film/chip size. It 
is just the apparent FOV that changes (one can use the term equivalent focal 
length, but that can also cause confusion, because then you need to state 
equivalent to what, though most people use 35mm, when that film size is no 
longer popular, then what will that mean?). With a small film/chip size, the 
moon will cover a larger percentage of the area of the detector. There is 
quite a bit of detail for such a short lens on the moon. The darkening of 
the northern limb is more than I expected.

Taras


On Apr 24, 2005, at 11:32 AM, Stan Richard wrote:

>Stuart, thanks.  The focal length was actually about 330mm, forgot about 
>the 1.6x crop factor.  This is 100% crop, sharpened up in PS.  The image is 
>just as the moon appeared to me visually looking thru the viewfinder, 
>suppose I could try to reduce the dynamic range but I don't think it would 
>look right.
>
>
>
>Stan Richard
>Events in the Night Sky
>www.nightskyevents.com
>
>
>
>
>----Original Message Follows----
>From: "Stuart Heggie" <Stuart.J.Heggie@sympatico.ca>
>Reply-To: Discussion of Film Astrophotography <astro-photo@seds.org>
>To: <stan.richard@hotmail.com>,"Discussion of Film Astrophotography" 
><astro-photo@seds.org>
>Subject: Re: [APML] OT: Penumbral eclipse
>Date: Sun, 24 Apr 2005 08:17:28 -0400
>
>Stan - nice one! Very sharp for a short focus camera lens. The image seems
>to have a very wide dynamic range - the brightest parts of the moon are too
>bright. Is this pretty well what came out of the camera? If not, you might
>try to reprocess it to retain the details in the brightest parts of the 
>moon
>without losing them in the penumbra.
>
>Stuart
>----- Original Message -----
>From: "Stan Richard" <stanrichard@hotmail.com>
>To: <astro-photo@seds.org>
>Sent: Sunday, April 24, 2005 7:02 AM
>Subject: [APML] OT: Penumbral eclipse
>
>
> > I hope it's ok to post this here as it is digital, got up early anyway 
>so
>I
> > went out and grabbed a shot of the eclipse.
> >
> > http://www.pbase.com/image/42489471/original.jpg
> >
> >
> >
> > Stan Richard
> > Events in the Night Sky
> > www.nightskyevents.com
> >
>
--
                         <end of message>
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* Taras R. Hnatyshyn                     tarashnat@earthlink.net *
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*  73°59'18.4"W 40°43'37.2"N    or    74°25'24.4"W 41°40'42.0"N  *
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