Adventures in Astrophotography

I’m not exactly sure why, at this late date, I have suddenly become interested in astrophotography. Looking through my blog posts will show occasional shots of the moon and a few star shots. The best Milky Way images came from North Dakota in 2015, where the Milky Way really popped in the dark skies. Just the camera on a tripod was good enough to capture some wide field views without star trails.

But recently I’ve had the desire to capture potentially more detailed long exposure images. Do do that requires the ability to move the camera in a way that tracks the motion of the stars across the sky in synch with the earth’s rotation. After a lot of web surfing and reading, I decided to get one of these:

The Orion Star Tracker, properly aligned on the North Star, will track the stars across the sky, allowing long exposures without start trails.

The package arrived the other day and I assembled it. It sits very nicely on an old Bogen tripod. I was, of course, anxious to give it a try, but with an 82% waxing gibbous moon, there were not a whole lot of stars visible. Nevertheless, I set up on our upstairs deck in the hopes I could see a couple of bright stars just so I could start to learn how to make the device work.

As the twilight faded, one bright star emerged high above the garage: Deneb. I could not see the North Star to get the polar alignment right on but made a fairly good guesstimate by setting the declination scale as close to 39 degrees as I could and them aiming the polar alignment scope in the direction as close as I could remember seeing it from past nights.

With my Olympus EM-1 MkII and a 25mm f1.8 lens mounted on the tracker, I swung it around and Deneb was bright enough to see in the viewscreen. I carefully focused on the star using the live view magnification that the camera provides.

This was a relatively short exposure but long enough to produce start trails if the tracking was not working. Not a great astrophotograph, but I felt it was a proof of concept.

Scanning around this image on the screen I noticed in the lower right corner, a line of star-like objects that were in such a straight line that I wondered if this might be something other than a star. An asteroid, perhaps. I zoomed in and cropped that area:

Fascinated by this grouping of objects, I started poking around to see if I could figure out what was going on.

I started with a program on my computer called “Redshift”, which is a very nice planetariam program. I noticed that in the general area of the sky, there was a label NGC-6802. Although the software’s display did not show this pattern, I looked up NGC-6802 anyway. This is what I found on 

It turns out that NGC 6802 was not what I was looking for but it was very nearby. I learned that what I was looking for was Brocchi’s Cluster (or Brocchi’s Coat Hanger). Also known as CR399.

So ends my adventure. My curiosity is still alive, even at my age and, perhaps, that’s one of the things that’s keeping me alive.

~ by Rsmith on July 10, 2020.

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