Learning to Use Seestar
An unusual number of clear, moonless nights in early February were a great opportunity to get more familiar with my new Seestar 50 automated telescope. It's so easy to carry it outside and begin observing after only 10 minutes of prep time!
On February 3rd I first targeted the famous Horsehead Nebula (IC 434) near the star Alnitak in Orion's belt. A recent firmware update now enables Seestar to take 20 or 30-second exposures in addition to the original 10-second option. So I tried using 20-second exposures for capturing the Horsehead. Image capture began successfully, but eventually stopped after running for 18 minutes. Apparently, tracking errors during 20-second exposures were too great to continue acceptable stacking. I employed the onboard light pollution filter which passes red hydrogen light. In spite of less accumulated exposure time than planned, the 18-minute result was reasonably nice.
I still have a lot to learn about image processing, however, because the previous image isn't as dramatically bright as I'd like. The red color is dull.
For the rest of the evening I reverted to the usual 10-second Seestar individual exposure times. Open star cluster M41 in Canis Major was my next target. The telescope tracked well and produced the next image after only 10 minutes of adding 10-second exposures.
Open cluster M46 in the constellation Puppis is an interesting object because planetary nebula NGC 2438 is included in the field of view. You can see the little green nebula to the left of M46 in the following image obtained by stacking 10-second exposures for 25 minutes. The planetary nebula is a foreground object lying along the line of sight to the cluster. It isn't actually part of the star cluster.
While seated comfortably inside my warm house I commanded Seestar to point to galaxy M81 in Ursa Major. This time I centered the galaxy instead of placing it on the edge of the field of view as I had done in a previous attempt. The northern celestial location of M81 diminished guiding errors during the 68-minute accumulated exposure time that produced the next image.
This evening's last target was the famous Rosette Nebula in the constellation, Monoceros. It's located to the left of Orion's bright star, Betelgeuse. This nebula, mostly glowing in red hydrogen light, surrounds a central star cluster NGC 2244. I employed Seestar's light pollution filter again and stacked 10-second exposures for 60 minutes. The camera's field of view is too small to capture the entire Rosette Nebula, so the image below only shows the right half of the full circular shaped nebula. Notice the strings of dark dust to the right of center.
Once again, I'm disappointed by how dull the red color appears. There is surely a way to correct this with image processing, but at this point, I don't know how.
During this night I learned some practical information about Seestar. Field rotation shows up as distorted areas on opposing diagonal edges of long exposure images. I've cropped these blemishes out of images displayed here. The central field of view isn't affected.
Seestar's battery inevitably ran low on this cold night with the telescope's dew heater continuously drawing power. Seestar starts complaining about low battery when the charge falls below 20 percent. The battery is good for 3 or 4 hours under these conditions. Extended operation time can be obtained by plugging Seestar into its battery charger while Seestar operates. In addition, over hours, my controlling tablet battery begins to discharge as well. The tablet can also be connected to its charger while working to extend its life.
It was well after midnight when I decided to quit. Shutting down and bringing Seestar inside took about three minutes, a wonderful advantage compared to hauling in several heavy components of my more complicated astrophotography equipment.
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