Dwarf Planet Eris (2nd attempt), M1
Posted: 28 October 2013
Clouds came in mid-day on Saturday, 26 October 2013. No observing. Clouds continued on Sunday, 27 October, but the sky cleared after sunset. The observatory was opened at 2047 MST, 66°F. There were some clouds low in the northwest, with a slight breeze blowing. The main goal for the night was a second attempt at imaging the dwarf planet Eris (magnitude +18.7). At 2055 MST, viewed the planet Neptune, followed by the planet Uranus, 83X.
At 2105 MST, slewed to the star Fomalhaut and began making some preparations for imaging. By 2126 MST, the clouds in the northwest were getting higher in the sky. I decided to monitor them to see if they would become a problem for imaging to the southeast (where Eris was). As it turned out, the clouds were not a factor. Mounted the D7000 DSLR at prime focus of the 8" LX200-ACF using an off-axis guider. At 2200 MST, did a focus test using Fomalhaut with a Bahtinov Mask. I then used SkySafari Pro on the iPhone 5s, connected to the telescope via the GC Wi-Fi Adapter, to GOTO Eris. As on the previous session, I had to slew a lot to get to a good guide star.
Began imaging at 2212 MST. Did a 10 minute, guided, ISO 6400 exposure, which I hoped would show movement assuming that Eris was not too faint for my equipment. I had previously determined that my photographic limiting magnitude was +17.48, so Eris might be invisible. Prior to opening the observatory for this imaging session, I received an email from Tom Wall of Tucson. He believed he had identified the location of Eris in my image from 25 October using Stellarium. Thanks, Tom. Using his location, I cropped the images from 25 October and 27 October to make this GIF animation:
Other than some digital noise, no object movement is evident. I will try again on my next session in the observatory.
I decided to also image M1 (Crab Nebula) this night. After letting it rise higher in the eastern sky, I did some framing test exposures while searching for a good guide star. I finally found a good star and did this guided 10 minute, ISO 6400, exposure (cropped from the full-frame image):
I completed imaging at 2340 MST. I viewed M1, 83X, at 2348 MST. Next, I viewed Jupiter, 83X. Only two moons were visible. I then began closing up for the night.
The observatory was closed at 0000 MST, 60°F.
I use an AppleScript to change the observatory status on my web site when the observatory is opened and closed, and to automatically tweet the status change. As I tweeted Friday evening, after running my script I discovered that my code broke with Mac OS X 10.9 Mavericks. However, using the technique and scripting library from this AppleScript site, I was quickly able to restore this capability and used it successfully when the observatory was opened and closed Sunday night.
Comments are welcome; use the Comments section below, or you can Email Me. Thanks.
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