Re: [APML] New TAK image - Cats Paw Nebula

["Monte Wilson" <montezinho@bigpond.com>]

Thanks to all with the info. Roland is right, I checked the illumination
through the back of the 6x7 with the shutter open and no film. This fall off
does start near the edge. Maybe the smaller hot spot is in my imagination.
If someone has the TAK or AP of similar size, they should be able to do this
too. The 6x7 Pentax is a wonderful tool. I have also had great results with
a 200mm lens on this body.

I will check my PS version to see what I can find about gradients.

Iview is marvellous. It saved the day for me.

Best regards

Monte







----- Original Message -----
From: "Mark Bohrer" <lurchl@ix.netcom.com>
To: <astro-photo@seds.org>
Sent: Wednesday, September 18, 2002 4:17 PM
Subject: Re: [APML] New TAK image - Cats Paw Nebula


> Monte:
> You've shown me what's possible with the Tak FSQ-106N. I have this scope
> and Extender-Q on a GM8, and an M6 with 50mm Noctilux and 135mm APO-Telyt
> for piggyback and a Nikon F2 for prime-focus shooting. I only hope one day
> through practice to have sufficient skill to approach your shot in
quality.
>
> Corner darkening (sometimes called vignetting) was a problem with the
Zeiss
> Hologon 15mm lens (and it's still a problem with my Voigtlander/Cosina
> 12mm). Zeiss used to include a special filter with the Hologon that was
> progressively darker towards the middle of a circular central zone to
> reduce it. This cutoff/decrease of brightness at the edge of the field is
> similar to what you're experiencing with the 6x7 camera on the Tak. I've
> read in various places about applying a circular gradient in Photoslop to
> mitigate the effect, but haven't tried it myself.
>
>
> >Having solved the file problem I am now in the game.
> >
> >Here is a Cats paw I did last week. E200 1 hr 6x7 on Tak fsq-106. Push 1
> >stop dev.
> >
> >I have only fiddled with it a little bit yet. It seems to be a rather red
> >scan. I am wondering if that area has a bit of  HII and it is fooling me
> >into thinking it is a colour balance problem.
> >
> >510kb file
> >
>
><http://www.tradepart.com/techinfo/catspaw.jpg>http://www.tradepart.com/tec
hinfo/catspaw.jpg
> >
> >Regards
> >
> >Monte
>
> Mark Bohrer
> www.kokophoto.com
> Pro mountain bike racing on the web
>
>
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