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Ursa Astronomical Association

Telescopic comet PANSTARRS - 14.9.2021 at 22.00 - 15.9.2021 at 00.20 Orimattila, Artjärvi, Viestikallio Observation number 101321

Visibility II / V

Jorma Ryske, Etelä-Suomen kosmol. seura

Comet C/2017 K2 (PanSTARRS) is quite far away 5.4au from both Earth and Sun. However, comet's nucleus is big, several tens of kilometers and that's why it's quite bright already, m1 around mag 12.5.

Image 1) 15x60s bin2, Baader Clear filter, star stacked, no flats
Image 2) 15x60s bin2, Baader Clear filter, comet optocenter stacked, no flats
Image 3) 12*300s bin2, Semrock 387nm/15nm filter, tracking and stacked to comet optocenter, no flats
Image 4) 3x15x60s bin2, Astrodon RGB, comet optocenter stacked, no flats

Image1 and image2 showing comet through L/Clear filter. 5' tail to PA 11° is visible. Measured m2 brightness 15.0 with aperture radius 6" with filter G/V.
Image3 is showing faint comet coma in near UV 387nm light, negative or minor observation of CN 3883Å gas.
Image4 RGB color image showing comets bluish coma indicating sublimation of carbon monoxide (CO)

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Additional information
  • Observation target
    • Comet
  • Title for the comet
    • Telescopic comet
  • Name of the observation target
    • C/2017 K2 (PANSTARRS)
  • Brightness in magnitudes
    • 12,5
  • Tail length
  • 5 arc minutes
  • Coma diameter
  • 1 kaariminuuttia
  • Weather
    • 7C=>4C, occasional thin clouds passing during L & R
Technical information

TS 305/1200mm Newton, TS KomakorrF4, QSI690, filters Baader Clear, Astrodon RGB, Semrock CN 387nm/15nm, mount CEM60. FoV 25' x 20'. North up, east left.

Comments: 3 pcs
Tapio Lahtinen - 19.9.2021 at 11.54 Report this

Interesting comet and quite long tail already.
Inclination 87 degrees so that is also pretty unususual.
Must start monitoring this now.

Hopefully it will be near naked eye limit a year from now.

Jorma Ryske - 19.9.2021 at 22.41 Report this

It will be nice mag10 morning comet from end of December until April. Unfortunately when it starts to be much brighter it will be summertime in Finland and it's also moving quite fast to lower declinations. It seems to be great object for observatories in southern Spain during summer :-)

Veikko Mäkelä - 20.9.2021 at 12.42 Report this

C/2017 K2 (PANSTARSS) kuuluu ns. ulomman Oortin pilven komeettoihin, joilla on tosi pitkä periodi ja apheli kaukana.  Viittasin tähän ja muihin samankaltasiiin komeettoihin verkko-Cygnuksen esitelmässäni (kohdasta 24:50 eteenpäin).

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