C/2009 P1 (Garradd) – OCT 31-NOV 1, 2011

Sketch of comet C/2009 P1 (Garradd)

Sketch of comet C/2009 P1 (Garradd)

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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

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