Fred Lehman
Once again and for the first time in almost five months, the clouds relented
on the day of a scheduled outing. I arrived shortly after sundown and set
up under perfectly clear skies. There was not as much as a breath of wind
to blow away the early evening mosquitoes, but they weren't a problem at all
later on when it was nice and dark. Since it has been quite a while since
my last imaging session, I was a little rusty and didn't get everything put
together properly till well after 10PM. I had just enough time before
moonrise to capture a couple of fine images of two familiar Milky Way
objects. Although I have shot each of them several times over the years, I
wanted to try them one more time with my new high-resolution camera.
Both images turned out spectacular, and I am quite pleased with the results.
I put an hour and twenty minutes on the Trifid Nebula (M20) and an hour and
forty minutes on the Dumbbell Nebula (M27). After taking a fresh set of
dark frames I packed up and headed for home, arriving about 4:30 AM. I
spent the next hour and a half processing the pictures and I finally got to
sleep just as the morning twilight was beginning to wash away the darkness
of the night.
I was accompanied by Marc Umlas and Don Ellington from SFDSO and a few of
the more adventurous members from the astronomy club of Fox Observatory,
the most hearty of whom stayed out till after 1 AM.
SXVF-M8C on an LX200-14 @ f/1.98 |
Trifid Nebula M20 in Sagittarius
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Dumbbell Nebula M27 in Vulpecula
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Due to its low altitude above the southern horizon, the photo of
the Trifid Nebula required special special processing to correct for the
prismatic effects of the Earth's atmosphere. To do this I first split the
raw stacked FITS file into separate R, G, and B images. The RED image was
re-sampled with a diagonal offset of +0.4 pixels (shifting it up and to
the left) and the BLUE image was re-sampled with a diagonal offset of -0.8
pixels (shifting it down and to the right). The GREEN frame was left
unchanged and the three colors were then re-combined into a single RGB image
again.
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