FreeLists / az-observing / [AZ-Observing] Re: Was Saturday Great or What???

["Jon Christensen" <jonc97@xxxxxxx>]

Those are all great pictures.  I'm torn between the snake or B86 or the 
trifid as my favorites.


Jon Christensen


----- Original Message ----- 
From: <ketelsen@xxxxxxxxxxxxxx>
To: <az-observing@xxxxxxxxxxxxx>
Sent: Monday, May 01, 2006 11:44 AM
Subject: [AZ-Observing] Was Saturday Great or What???


Hi All-

Sorry I'm a little late to chime in here and affirm what you were all
saying about saturday night.  Roger Ceragioli and a friend joined me near
the 6,000 foot level at Kitt Peak - they doing visual observing and I was
expanding my D20a portfolio.  Once I had the autoguider going, I was able
to join them a few times - the seeing was quite superb, demonstrated by
the excellent views of Jupiter thru their 8" scope at nearly 300X.

I was shooting thru my 11.25" F/3.5 with a Paracor and the Canon 20Da.
Here are a few of the shots:

First off, a slightly cropped view of the moon, exposed for the earthshine
http://alice.as.arizona.edu/~ketelsen/Moonlongexp_s.jpg

Took a long time to get some momentum, but eventually got set up and a
guide star on M101.  This is 20 minutes of exposure, aligned and levels
adjusted.  By the way, I turn on the auto dark subtraction, so the 20
minutes of exposure also had 20 minutes of dark subtracted as well.
http://alice.as.arizona.edu/~ketelsen/M101ave5_s.jpg

I did a sequence on SW3 - I thought I was autoguiding on the comet
nucleus, but about the time it passed a star near the beginning of the
sequence, it obviously jumped to the star.  I took a break in the van and
when I came back, the comet had moved to near the edge of the field.  So
much for keeping the comet centered...  Anyway, here is a single 3 minute
exposure from that sequence:
http://alice.as.arizona.edu/~ketelsen/SW3_s.jpg

Next to my faves - I'm a fan of dark nebulae, so one of the first on my
photographic hit list was the Snake Nebula, B72.  This one just blew me
away as I was watching them come out on the LCD screen.  Cropped slightly
from the full frame, it is an average of 5 - 4 minute exposures. All
except the moon were at an ISO of 1600.
http://alice.as.arizona.edu/~ketelsen/B72ave5_s.jpg

Another favorite visual object is B86 above the spout of the Teapot.  This
is in such a bright Milky Way cloud that I had to drop the exposures down
to 2 minutes!  This is an average of 6 of them, 12 minutes total exposure:
http://alice.as.arizona.edu/~ketelsen/B86ave6_s.jpg

And just before dawn broke, I got in a sequence on M20, another favorite
of mine, and again, was astounded by what the 20Da was able to capture in
a short time.  This is an average of 5 frames, 16 minutes total exposure:
http://alice.as.arizona.edu/~ketelsen/M20ave5_s.jpg

It was my first all nighter for some time - I had wanted to start
collecting summer Milky Way objects for a Grand Canyon talk, and
fortunately, I was inspired to stick to it and stay up.  A draining night,
but a great time.  I hope you all enjoy the images...

-Dean





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