Comet 17P/Holmes - 31 Oct 07


Finally also this comet start to develop a (small) tail, now mainly of gas (as can be found from the blue color). The main tail component is at PA 210° and a secondary tail is at PA 245°, extending from the optocenter respectively about 32' and 26'. Many other filaments seems to be present, as can be evidenced with a highly overprocessed blue frame (see below). The dust coma is 10' diameter and the gas coma is about 33'.



A GIF animation of 3.5 hours time interval that show internal structures evolutions and expansion. Larson Sekanina 10°.


A logarithmic photometric profile in the sunward direction show the real dimensions in arcminutes.


Wide field view from my observatory, with the Schmidt camera observing comet Holmes. 31 oct 2007, 23.33 UT. Tech details: 8 mm f/3.5 objective, Canon EOS 350D, 60 s exposure, ISO 100.

Technical Data
Optics Schmidt camera 400/300/615 (Zen optics)
Focal Lenght 615 mm
Focal Ratio f/2,0
Exposure Time Total 90 min. in frames of 30 s (R,G) and 120 s (B) each.
CCD A camera with Kaf-6303e
Sensor Kaf-6303e class 1
Filters RGB Astronomik
Chip emperature
 -30°C
Location Tradate (VA, in Pianura Padana, Italy) at 300m height
Date and time of exposure start 31 october 2007, RGB 19.03 - 19.57 - 20.55 UT
Mount Astrosystems fork mount
Tracking -
Temperature and humidity T=6°C, RH=98%
Notes Internal coma elaboration with Larson-Sekanina. Stars color alignment to compensate comet motion.

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