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Naked Eye M33 Galaxy, Dwarf Planet Eris (3rd imaging attempt)

Posted: 31 October 2013

Monday, 28 October 2013, was cloudy and windy, both of which continued on Tuesday. Missed two good ISS passes. Wednesday, 30 October 2013, had clear skies and no wind. The observatory was opened at 1813 MST, 63°F. The neighbor to the northeast had his bright floodlight on (which he had said was for his dog). At 1823 MST, viewed Venus, 83X. A nice half-phase was visible.

At 1833 MST, I added a focal reducer to the 8" LX200-ACF and switched to a 1.25" 40mm eyepiece (31X). Then viewed M22 (globular cluster). At 1835 MST, slewed to the Helix Nebula, which was faintly visible a few minutes before the end of astronomical twilight. Had a nice view of the Helix Nebula at 1851 MST using the low magnification. Next was M31 (Andromeda Galaxy) and its companion galaxies M32 and M110. All three were well within the low magnification field-of-view (FOV). Then viewed the Double Cluster, 31X. Both open star clusters were well inside the FOV.

Slewed to M33 (Triangulum Galaxy) at 1900 MST and viewed it at 31X. It wasn't quite high enough for good viewing through the telescope. At 1906 MST, viewed M33 using 7x50 binoculars. And at 1912 MST, I detected M33 (Magnitude +5.72) using my naked eyes. At a distance of 2.8 million lightyears, M33 is the most distant object visible to the eye without using optical aid. I also viewed M33 using the 2X nightscope. At 1931 MST, I returned to the 8" telescope and viewed M33 using 31X. Some spiral structure was visible.

Slewed to NGC6888 (Crescent Nebula) and viewed it at 31X. Some nebulosity was faintly visible. Added the Oxygen-III filter; the nebulosity was easier to see. I then switched back to the 2" 24mm UWA eyepiece (without the filter); the nebula actually looked better through this eyepiece with the focal reducer. Removed the focal reducer.

At 2008 MST, took a last look at M33. I then did a tour of DSOs in Aquarius, 83X: M72 (globular cluster), M73 (open cluster), NGC7009 (Saturn Nebula, planetary nebula), M2 (globular cluster), and NGC7293 (Helix Nebula). I slewed to the star Fomalhaut and SYNCed the AutoStar in preparation for my upcoming dwarf planet Eris imaging attempt.

At 2027 MST, slewed to Eris (Magnitude +18.7). I prepared the D7000 DSLR for prime focus imaging. At 2039 MST, with the temperature now at 48°F, I decided to take a short "warm up" break. I put the telescope to sleep and closed the observatory dome. At 2135 MST, I returned to the observatory and opened the dome. The temperature was 47°F. The neighbor had turned off his floodlight. (Thanks)

Mounted the D7000 DSLR at prime focus using the off-axis guider and did a focus test with the Bahtinov Mask using Fomalhaut. I used SkySafari Pro on my iPhone 5s and the GC Wi-Fi Adapter to GOTO Eris. When I looked in the illuminated reticle eyepiece, a good guide star was in the FOV (unlike on the previous two imaging attempts). At 2151 MST, I began a 10 minute, guided, ISO 6400 exposure. As I noted on my previous report, Tom Wall of Tucson had determined where Eris was located on my image of 25 October. No obvious movement was detected on a "blink comparison" of images made on 25 and 27 October. This image is Tom's area where Eris should be, "blinked" on 27 October and 30 October:


This next image, minimally cropped from the full frame images, shows a blink comparison on 27 and 30 October:


In both images, other than some "digital noise", no object movement is detected. Consequently, it appears that Eris is too faint at Magnitude +18.7 to be imaged with my equipment. I had previously determined that my photographic limiting magnitude is +17.48, so that still stands.

The observatory was closed at 2221 MST, 46°F.

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

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