Observation Notes:
I enjoyed a very nice view of C/2009 P1 (Garradd) tonight. It’s been too long since I’ve gotten out for a recreational observation. The coma was moderately condensed with distinct elongation to the southeast. Further scrutiny revealed a prominent tail about 10 arc seconds in length pointed to the southeast at a PA of 115°. The south edge of this tail had a more abrupt spine while the north edge was softer. At a northeast PA 67°, a shorter, more delicate tail drifted about 5 arc seconds from the central condensation. Overall, there was an impression of a diffuse hood draped across the northwest side of the coma.
At times, I thought I detected the slightest hint of green in the coma, but I wasn’t certain enough to include it in the sketch. The warmly colored, ninth magnitude glow of TYC1559-1174-1 decorated the north edge of the view. I looked for evidence of the comet’s motion 90 minutes later, and there appeared to be some slight drift to the northwest. However, I hadn’t plotted the star field with enough density close to the coma to estimate the apparently slow motion with enough accuracy.
OCT 31, 2011 UPDATE: I re-observed the comet the following night (NOV 1, 2011, 0330 UT) and noted motion of about 8 arc minutes to the west-northwest at a PA of about 287°.
Subject | C/2009 P1 (Garradd) |
Classification | Comet |
Position* | Hercules: [RA: 17 37 31.2 / Dec: 18 44 35.5] |
Size | Coma: 5 arc minute diameter Degree of Condensation: 6 Dust tail: 10 arc minute length at 115° PA Ion tail: 5 arc minute length at 67° PA |
Brightness* | 6.5 vMag |
Date/Time | OCT 30, 2011, 7:00 PM MST (OCT 31, 2011, 0200 UT) |
Observing Loc. | Flagstaff, Arizona, USA – Home |
Instrument | SkyQuest XT8 (8 inch f/5.9 Dobsonian) |
Eyepieces/Mag. | Pentax XW10 (120X) |
Conditions | Clear, calm, 1st quarter moon |
Seeing | 5/10 Pickering |
Transparency | SQM: 20.0 |
*Sources | Starry Night Pro Plus 5.8; Aerith.net |