Re: [APML] Funky Purple Horsehead Questions

[Allan & Julie Whetzel <whetzel@cox.net>]

Thanks to everyone that replied -

I now know that a huge part of the problem was due to a "stupid rookie 
trick." My VueScan software defaults to an automatic color balance 
selection for everything it scans. Simply turning off this "feature" 
and rescanning produces a much better effort (see new link) - should 
have known.

The hot-pink band was on the original slide so it must have been a 
light leak - though the two other shots from the trip show no such 
effect. The "comet tails" are barely noticeable now (there was no 
filter used during the exposure). They are odd because a 1.5 hour 
exposure on Tech Pan taken directly after this shot shows no hint of 
them (the film change was the only difference in the setup).

The vertical lines that stood out in the purple version appear to be 
gone as is the bulls-eye, but I am concerned about Chris's thought that 
the scanner may be on it's last legs.  I'm curious if a proper 
processing of this image (or a good one that was worth the effort) 
might result in the return of these lines? Every other scan I've done 
with it has looked great so I'm hoping it's not on its way out.

Thanks for the help!


New Scan:

http://www.members.cox.net/whetzel/horsehead2.jpg

Funky Purple Scan:

http://www.members.cox.net/whetzel/horsehead.jpg












On Thursday, January 22, 2004, at 04:38 AM, Chris Schur wrote:

> Allan,
>
> The comet "tails" appear to be ghost images from somewhere in your 
> optical
> system.  Most likely you can look at your original slides and if they 
> are
> there, it is on your astrocamera setup.  Did you use a filter in the 
> system,
> like a LPR?
>
> Purple is the color you can get from using a light pollution filter in
> series.  Or of course, from nearly expended chemistry when it was 
> developed.
>
> The scan lines are from your scanner, and mine did the same thing near 
> the
> very end of its life. (sprintscan 35)
>
> Chris Schur
>
> -----Original Message-----
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org]On Behalf Of Allan & Julie Whetzel
> Sent: Thursday, January 22, 2004 12:32 AM
> To: Discussion of Film Astrophotography
> Subject: [APML] Funky Purple Horsehead Questions
>
>
>
> Hello everyone-
>
> A bunch of newbie questions that I could not find answers for in the
> archives!
>
> I shot this a few nights back using E200. Didn't expect it to be great
> - but was surprised at a number of things when I got it back from
> development and was hoping the group could help me understand what's
> going on. First off - it was a 60 minute exposure with an 8"  f9 VC200L
> from Vixen guided by an ST-4 on a G11 mount taken with an Olympus OM1.
> It was developed by a local lab with no special instructions and I
> scanned it on my SprintScan 35 plus.
>
> Questions are:
>
> Why do the star images on the left and right sides have "comet tails"
> pointing toward the center?
> Why's it so darn purple & pink (is this usually just processed out)?
> Are the vertical lines across the entire image typical of this film
> (grain characteristics) or is it bad processing?
> What would cause the hot pink vertical line in the lower left?
> Also - its hard to see but there is an odd bulls-eye shaped
> imperfection in the lower center - any ideas?
>
> E200 seems to be the preferred film these days - but based on this
> result  - I need to work out a bunch of issues!
>
> http://members.cox.net/whetzel/horsehead.jpg
>
> Any help is much appreciated!
>
> Allan
>
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