[APML] Re: IC 2948 image

[axm2@canopus.physik.uni-potsdam.de]

On Sat, 2 Mar 2002, Tony Hallas wrote:

> ... is this the Vixen coma corrector or one that was custom made for
> the scope?

It is the Vixen coma corrector. It works pretty well, with only a slight
amount of coma near the edges (as Shekhar correctly noticed).

> I'm impressed with the stars you got... at
> f/4 all kinds of opportunities open up for shooting fine grain films
> and tricolor...interesting!

I wish I had the time for tri-color work...
Actually, my scope is probably closer to f/4.3, since I masked off the
outer 4 mm of the primary mirror (following a suggestion on this list a
few years ago). These scopes often suffer from a turned down edge,
resulting in diffuse halos around bright stars with the retaining clips
visible as dark bands - as, for example, in this 6-year-old M42 image:

http://canopus.physik.uni-potsdam.de/~axm/photo.cgi?Image=images/1996-07_04

One other nice thing about this scope is its ruggedness - collimation was
still fine after 1500 km on dirt roads, whereas the Dec motor on my Super
Polaris mount was shaken loose in its dovetail socket.

On Sat, 2 Mar 2002, Shekhar Borde wrote:
 
> How do you take all your stuff to South Africa?  By air freight?

The scope went as air freight, while the other equipment was put in the
checked and carry-on baggage of me and my friend, with a lot of 'creative
packing'...

Clear skies,

Axel


-- 
Axel Mellinger  <http://canopus.physik.uni-potsdam.de/~axm/astrophot.html>






--  APML Archives at <http://astro.umsystem.edu/apml/>  ---
             Unsubscribe at <majordomo@seds.org>