[APML] More Supra 400 analysis, plus a cold weather gain

[Alan Voetsch <critter12952@yahoo.com>]

Hey all,

Just picked up the new batch of pictures. I'm learning
more all the time. Some might say, "about time".
Here's what I observe. 

1. Minimum optimum exposure time for me (f/10) is
about 120-140 minutes. Less than that and it looks
underexposed. Keep in mind that I live in a rural area
with a little skyglow in the NE from Medford Oregon.

2. I shot half a dozen shots between 260-320 minutes.
Yeah. None of them show a single sign of
over-exposure. Most appear to have near perfect
exposure .

3. Another dozen were exposed between 140-260 minutes.
Most of these appear to have close to perfect
exposure.

4. Other than a 110 minute shot of M57, all the
shorter (60-135 minutes) shots needed more exposure
time. A 135 minute shot of M74 was way underexposed.

5. There were seversl shots of M33 on the roll. Shot
on different nights with different ambient
temperatures. Two were back to back on Oct 30 when it
got below freezing around 9:00 P.M., halfway through a
4 hour exposure. The next shot was a one hour exposure
(the shortest time I even think about nowadays),
during which, the temp was below freezing the entire
time. The 4 hour shot had better exposure than the one
hour, but not all that much. Compared to the much
longer shot, the shorter one looked like a 120-150
minute shot. This leads me to believe that there was a
film speed gain of some kind that occured to the short
exposure. But for some reason it did not benefit the
previous exposure that much.

7. 4 hours appears to be about perfect for most deep
sky objects. Longer for face on spiral galaxies and
fainter nebulae.

8. A 260 minute shot of M31's core was just starting
to show some of the intricate dust detail in the core
that Rob G's masterpiece shows so well.

On a positive note, it looks like most of my guiding,
or mount related issues are taken care of and I'm
really stoked about what I saw when I opened up the
film envelope. Finally, after years of trying, a good
Horsehead shot. A good Running Man shot, too bad I
mis-framed it. Excellent M33, and Bubble Nebula, and
Cocoon. I'm going to need more wall space.

Now a challenge. I had 67 hours of exposures on this
roll (not quite as much as last month), anyone ever
shoot longer than that on one roll?

Respectfully submitted,
Alan

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