Contact information

Ursa Astronomical Association
Kopernikuksentie 1
00130 Helsinki

Ursa Astronomical Association

Kaukoputkella näkyvä komeetta NEOWISE - 18.3.2021 klo 21.31 - 18.3.2021 klo 23.45 Helsinki, Maunula Observation number 96924

Visibility I / V

Jorma Ryske, Etelä-Suomen kosmol. seura

Comet C/2021 A2 (NEOWISE) is now much dimmer than I last observed it at February 16th. In this 115min exposure using 387nm narrowband filter cyanogen CN 3883Å radical gas coma diameter is 0,6'/40.000km and wide fan-shaped cyanogen gas tail length 1'/60.000km towards PA 330° is visible. Comet current distance from sun is 1,62au and from earth 1,43au. I took also R channel photometric image and although the image had poor S/N I measured comet R channel brightness as 16,3mag. CN channel brightness measurement is difficult because lack of 3883Å reference stars, not very scientific but when using B channel reference stars I measured comet CN coma roughly brightness as 15,1mag.

More similar observations
Additional information
  • Havainnon kohde
    • Komeetta
  • Kohteen nimi
    • C/2021 A2 (NEOWISE)
  • Kirkkaus magnitudeina
    • 16,3
  • Pyrstön pituus
  • 1 kaariminuuttia
  • Pään läpimitta
  • 0,6 kaariminuuttia
  • Sää
    • SQM-L 22:30 17,63 Zenit (snow on ground) -5C
  • Komeetan otsikko
    • Kaukoputkella näkyvä komeetta
Technical information

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

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