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Dwarf Planet Eris (1st attempt)

Posted: 26 October 2013

Clouds came in on Wednesday, 23 October 2013. No observing. Skies dawned clear on Thursday, 24 October, but clouds returned mid-morning and lingered into the night. No observing. The sky was clear on Friday, 25 October and the observatory was opened at 1815 MST, 77°F. Viewed Venus, 83X, at 1821 MST. At 1832 MST, slewed to the Helix Nebula and began waiting for astronomical twilight to end (at 1903 MST). Switched to a 40mm eyepiece (50X). At 1835 MST, the northeast neighbor turned on his floodlight (which he had said was for his dog). At 1849 MST, the Helix Nebula (in the southeast) was visble. While observing the nebula, a satellite passed through the field-of-view.

At 1854 MST, I began observing the following at 50X: M16 (Eagle Nebula), M17 (Swan Nebula), M20 (Trifid Nebula), M8 (Lagoon Nebula), M27 (Dumbbell Nebula), M57 (Ring Nebula), NGC6888 (Crescent Nebula), and Helix Nebula. All were good views at this low magnification. I then did some filter tests on these same objects:

Light Pollution Reduction (LPR): Really improved the view of M8, M16, M27, and M57. There was no change on M17 and Helix. It hampered the view of M20. Some NGC6888 nebulosity was barely visible (slightly better than no filter).

Oxygen III (O-III): Really improved the view of M8 and NGC6888, but hampered the view on M16, M17, M20, M27, M57, and Helix.

Hydrogen Beta (H-β): View slightly improved of M8, but hampered the view on M16, M17, M20, M27, M57, NGC6888, and Helix.

Northeast neighbor turned off the floodlight at 1943 MST. (Thanks.) But then the new neighbor to the south turned on a bright floodlight near the top of his house and essentially blinded me as I was looking towards the south at the time. Fortunately, it was on less than a minute, but I had to take some time to dark adapt my eyes again. Once I got dark-adapted again, I was able to resume the filter tests (including above).

At 1956 MST, viewed M31 (Andromeda Galaxy) and its companion galaxies M32 and M110, 50X. Lovely view at this low magnification. M31 spiral arms were visible quite a distance from the galaxy nucleus. At 2005 MST, viewed M45 (the Pleiades), 50X. It was too low in the sky to see any nebulosity but the stars of the Pleiades were nice at this low magnification. I then switched back the 2" 24mm UWA eyepiece (83X).

At 2014 MST, slewed the 8" LX200-ACF to the Dwarf Planet Eris, which was at opposition on 15 October 2013. Currently Eris is at magnitude +18.7, which is fainter than my previously determined photographic limiting magnitude of +17.48. But I would try to image it later this night anyway. It will take at least two nights of imaging to show movement.

While waiting for Eris to rise higher in the sky I did some terrestrial and sky viewing using my 2X nightscope. I also prepared the D7000 DSLR and ShutterBoss remote shutter release. At 2143 MST, slewed to Fomalhaut and did a focus test image using a Bahtinov Mask. I then powered on the GC Wi-Fi Adapter and used SkySafari Pro on the iPhone 5s to GOTO Eris. I had to slew around a lot to locate a guidestar in the illuminated recticle eyepiece on the off-axis guider. So I may have moved Eris out of the camera's field-of-view.

This image is a 10 minute, guided, ISO 6400 exposure. I briefly tried identifying stars in the image but was unsuccessful. North is at the top in this correct view.


I plan to take a second image on 26 October to hopefully show some movement in an object. Of course, since the Dwarf Planet is so faint, I will probably not be able to capture it.

The observatory was closed at 2246 MST, 57°F.

Comments are welcome; use the Comments section below, or you can Email Me. Thanks.

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