Re: [APML] More New Images Posted

["Chris Schur" <cschur@cybertrails.com>]

John, that looks like it will be an excellent performer for Milky way
fields, with its sharp edge to edge performance.

Chris Schur

----- Original Message -----
From: John C. Mirtle <spampit@shaw.ca>
To: Discussion of Film Astrophotography <astro-photo@seds.org>
Sent: Monday, July 28, 2003 5:27 PM
Subject: [APML] More New Images Posted


>     It's been a while since I have done this, but - I have some new
images!!
> These are my first-light images on a new mount with a new optical tube.
> Manfed Wasshuber got me interested in the Vixen VC200L as a way of getting
a
> longer focal length without all the "gotcha's" of an SCT. Last night's
> effort bore fruit, and all 3 would have been worth posting if I didn't
> insist on manually guiding one of them. :-)
>     The Vixen really does appear to be flat field, I cannot see any
> difference in the star images from centre to edge with tech pan.
Vignetting
> is minimal, diffraction spikes included and focus is easy at F9! I used an
> ST4 to guide using a Lumicon NEG. The off-axis images focus up nicely to
> points, instead of the comatic blob found in Newtonians. As a result, it
was
> very easy to set up and focus with the ST4 through the NEG. The background
> is a bit uneven with the NGC891 shot, due to my tech pan being over 1 year
> old. Comments welcome......
>
> http://members.shaw.ca/jmirtle/n891.htm - full frame
> http://members.shaw.ca/jmirtle/m71.htm - cropped 50%
> http://members.shaw.ca/jmirtle/equip.htm - Vixen photo at bottom of page.
>
> John Mirtle
> Calgary, Ab. Canada
>
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