We made it to Casper! My friend and fellow amateur astronomer Sarah and I are here for ASTROCON and the solar eclipse! And
we made it to the remote observing site. It is on the back side of Casper
Mountain, about a 45-minute drive up switchbacks and along a several-miles-long
dirt road. We got there before sunset,
and I set up a timelapse to record it.
It was beautiful up there! There
was a hill near the site that we climbed up as well to get a better vantage
point. The site blocked the light from
Casper to the north, and was very dark everywhere else. It is rated dark green on the Bortle scale.
My first goal of the evening
once it got dark was to try to autoguide the NexStar mount. It connected all right, but after several
attempts at calibration, I realized that it wasn’t going to work because of
backlash. I turned off the
anti-backlash, and when I do that, it takes a few seconds at speed 5 or 6 to
unwind the gear, so basically at guiding speeds, it was going to take a much
much longer time than would work for guiding.
So I gave up and decided to do without it. Back when I first started out, I could take
25-second images on my 8-inch SCT if I wanted to keep about 70% of them (the
rest lost to periodic tracking error), and I figured I could do better with the
much-shorter focal length Borg 76ED (500mm as opposed to 2000mm on the
SCT). However, I am still limited by
field rotation. Luckily, the light-mount
astrophotography book I have has a nifty table with how long you can image at which
altitudes and azimuths before field rotation will appear (starting with the
premise that a maximum of 0.125 degrees of star movement in a single frame is
acceptable). Looking almost due south at
the Milky Way, this turns out to be 30 seconds.
So that’s what I shot at. I first
imaged M17, the Swan Nebula, and then M8 and M20, the Lagoon and Trifid Nebulae
together.
While the images were going,
Sarah and I wandered over to the rest of the ASTROCON attendees who were up at
the site to look through their scopes.
We got some very nice views of M27 Dumbbell Nebula, M57 Ring Nebula, the
Helix Nebula, M31 Andromeda Galaxy, M13 globular cluster, and I think maybe a
few others, but I can’t quite remember
The wind finally died down
later in the evening, but it was still chilly up at the 6,700 ft elevation with
the breeze. Sometimes a warm breeze
wafted through. We left around 1:30 AM
to make the 45-minute drive down the winding dirt road back to Casper.
The images came out
surprisingly well for only be 30 seconds long!
Very exciting. It turns out to be
much easier to image with the refractor, of course! It just goes to show that aperture doesn’t
always win in astrophotography.
Date: 17 August 2017
Location: Casper Mountain, WY
Object: M17 Swan Nebula
Camera: Nikon D5300
Telescope: Borg 76ED
Accessories: Hotech SCA field flattener
Mount: Celestron NexStar SE
Subframes: 95x30s (48m), ISO-1600
Darks: 20
Biases: 20
Flats: 0
Temperature: 53-55F
Date: 17 August 2017
Location: Casper Mountain, WY
Object: M8 & M20
Camera: Nikon D5300
Telescope: Borg 76ED
Accessories: Hotech SCA field flattener
Mount: Celestron NexStar SE
Subframes: 88x30s (45m), ISO-1600
Darks: 20
Biases: 20
Flats: 0
Temperature: 53-55F
The eclipse is fast-approaching, and the weather is looking promising for Monday! I've got my BackyardNikon script all ready to go, and I spent last weekend practicing and refining the script. Now we wait!
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