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Ursa Astronomical Association
Kopernikuksentie 1
00130 Helsinki

Ursa Astronomical Association

Kiikarikomeetta ATLAS - 30.3.2020 klo 22.28 - 31.3.2020 klo 01.07 Helsinki, Maunula Observation number 89526

Visibility III / V

Jorma Ryske, Etelä-Suomen kosmol. seura

Comet C/2019 Y4 (ATLAS) is now 1,05au from earth and 1,50au from sun and brightening all the time.


Image 1) Astrodon G filter showing 8' diameter coma and 5' tail towards PA 120°, exposure time 10 minutes.

Image 2) Astrodon R filter showing 2' diameter coma and 4' dust tail towards PA 120°, exposure time 15 minutes.

Image 3) Astrodon B filter showing 4' diameter coma and 8' tail towards PA 120°, exposure time 10 minutes.

Image 4) Semrock CN 387nm narrowband filter showing cyanogen 3883Å gas coma about 18' diameter and dim tail towards PA 120°. Exposure time 60 minutes. Cyanogen gas coma visible here is almost ~800.000 km in diameter.

Image 5) Image 4 processed with CometCIEF showing tail 4' towards PA 120° which is scattered sun light from dust tail particles visible in R filter image. Towards PA 20°-40° is some cyanogen morphology visible but SN is too low. (CometCIEF Samarasinha, N. H., Martin, M. P., Larson, S. M, 2013. Cometary Coma Image Enhancement Facility, )

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Additional information
  • Havainnon kohde
    • Komeetta
  • Kohteen nimi
    • C/2019 Y4 (ATLAS)
  • Kirkkaus magnitudeina
    • 8
  • Pyrstön pituus
  • 8 kaariminuuttia
  • Pään läpimitta
  • 18 kaariminuuttia
  • Sää
    • -4C
  • Komeetan otsikko
    • Kiikarikomeetta
Technical information

TS 305/1200mm Newton, TS KomakorrF4, QSI690, Astrodon G, R, B, Semrock CN 387nm/15nm, CEM60. FoV 36' x 29'. North up, east left.

Comments: 2 pcs
Tapio Lahtinen - 1.4.2020 klo 14.49 Report this

Unusual that blue filter shows longest tail.

Jorma Ryske - 1.4.2020 klo 19.36 Report this

Blue filter image showing quite strong tail compared to other wavelengths might indicate that tail contains also CO+ ion gas which has several emission lines between 400nm and 430nm. Interesting, this must be observed more.

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