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Ursa Astronomical Association
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Ursa Astronomical Association

Binocular comet ASASSN - 21.10.2017 at 22.51 - 21.10.2017 at 23.10 Orimattila, Artjärvi, Tähtikallio Observation number 68274

Visibility IV / V

C / 2017 O1 (ASASSN) Filmed on the second night of the October work. We photographed this comet a month earlier in the data, . 1Picture. summary image according to the stars, the movement is clearly visible.
2Picture. first picture, measured 19: 51: 02UT 04h48m26.74s + 58d48'50.4 "coma 13.6mag, Horizon 19: 51UT 04h48m26.85s + 58d48'48.8" 12.54 / 15.72mag.
3Picture. last picture in the series, measured 20: 09: 56UT 04h48m27.49s + 58d49'42.6 "13.6mag, Horizon 20: 10UT 04h48m27.53s + 58d49'41.1" 12.54 / 15.72mag. TYC 3745-788-1 v.11.64mag stars used for brightness calibration.
The total brightness observation could not be performed because the tail covered too many bright stars. Koma's measurement was also well above the upper edge compared to Horizon's estimate of 15.7mag => measured 13.6mag. , the problem is probably the size of the measuring circle. When does a coma turn into a tail? Needs a different measurement tool well to succeed.

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Additional information
  • Observation target
    • Comet
  • Name of the observation target
    • C/2017 O1 (ASASSN)
    • Näyttävä
  • Weather
    • Puolipilvisyyden seljettyä osaan taivasta hyvä säätila.
  • Title for the comet
    • Binocular comet
Technical information

Alluna RC16, C415 / 3320, SBIG 1001E, filter L, 10 x 120s

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