Re: [APML] Image: Jeff Ball's Comet Ikeya-Zhang

["Bert Katzung" <katzung1@attbi.com>]

Jeff, that is a great comet shot---one of the best yet! What do you figure
is the FOV of your 6x7 on the A-P 130? About 4.5 - 5 degrees? Was the shot
cropped? I assume you use the A-P flattener? Keep up the good work!
My latest effort is at
http://www.astronomy-images.com/images/comets/Ikeya-Zhang-14-18-Mar.htm but
not as nice. I've got to get my 6x7 hooked up!
Bert


----- Original Message -----
From: "Jeff Ball" <jeffball@netacs.net>
To: "Astro-Photo" <astro-photo@seds.org>
Sent: Friday, March 22, 2002 12:00 PM
Subject: [APML] New Image: Comet Ikeya-Zhang


> What a nice comet.  Hope you have had a chance to view it.  Here is my
> shot from March 10.  A special thanks to Kirk Rogers for scanning the
> slide!  The tail has changed so much from day to day.  This is one 15
> minute shot on Fuji Provia 400F.  I have now shot with this film on two
> occasions and I must say I am very impressed.  The grain structure is
> very small.  It looks great on galaxies.  It seems to have worked well
> on Comet Ikeya-Zhang.  I am now back to using medium format thanks to
> this slide film.  I used PW pro to remove some vignetting and then the
> Sean Walker method for removing some uneven field illumination.  My
> first attempt at removing uneven field illumination with the Sean Walker
> technique resulted in some "wavy" artifacts near areas of transition
> from lighter to darker areas.  Using PW Pro oval gradient and then using
> the S. Walker technique helped minimize these artifacts.  I went with a
> blur of 70 pixels I believe.  I used a slight smoothing with SGBNR on
> the darker background.  Still not as smooth as I would like, but, it is
> my best for now.  Hope the show gets better in April!  Comments welcome.
>
> http://www.astro-photography.com/i-z.htm
>
> Jeff Ball
> www.astro-photography.com
> Ohio Valley Astronomical Society
> www.ovas.org
>




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