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Observation Notes:
It’s hard to believe that it’s been a month since I last sketched this comet. It has truly become monstrous. To the naked eye, it is a large soft patch glowing in Perseus, and is still an incredible thing through binoculars. I no longer see any color in it–just a pale gray. It still possesses that trilobite appearance, but is much softer now. There is no visible pseudonucleus, and the central fan has become a soft spine. It looks to me like the southwest half of the coma is brighter.
Using the astrometric eyepiece for measurements has been out of the question for some time now. Based on my sketch and comparison to the star field in Starry Nights Pro, I made some rough estimates:
- Central Fan: 12 x 60 arc minutes
- Coma: 60 x 75 arc minutes
| Subject | 17P / Holmes |
| Classification | Comet |
| Position* | 04:00 UT – Perseus: [RA: 03:06:57.2 / Dec: +48:13:53] |
| Size | Central Fan: 12 x 60 arc minutes Coma: 60 x 75 arc minutes |
| Brightness* | ~ 3.0 vMag |
| Date/Time | December 6, 2007, 9:30 PM (December 7, 2007, 04:30 UT) |
| Observing Loc. | Flagstaff, AZ – Home |
| Instrument | 15 x 70 Oberwerk Binoculars |
| Eyepieces/Mag. | – |
| Conditions | Clear, breezy |
| Seeing | 4/10 Pickering |
| Transparency | Mag 6.0 NELM |
| *Sources | Aerith.net; Starry Night Pro Plus 5 |
*Based on published data.