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Ursa Astronomical Association
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00130 Helsinki

Ursa Astronomical Association

Binocular comet Wirtanen - 11.1.2019 at 17.50 - 12.1.2019 at 05.00 Helsinki, Maunula Observation number 80336

Visibility III / V

Jorma Ryske, Etelä-Suomen kosmol. seura

46P/Wirtanen is still actively emitting CN cyanogen radical gas jets and it's distance from Earth is about 0,18AU. Here in first image Wirtanen is exposed 3 hours at near UV 387nm narrowband wavelength, where about 30' diameter coma is visible. In the second image Wirtanen is exposed with R filter, where short dust tail of length 3' toward PA 210° is visible.

I made also almost all night long exposures with CN 387nm cyanogen filter, totalling of more than 10 hours of 5 minute exposures during 11 hour of observing time. Few clouds was passing over during evening and meridian flip must also be done, so the animation is not exactly continuous. Third image/animation is the result of these 10 separate one hour stacked exposures showing corkscrew / pinwheel effect. 

Animation 1) Exposures with CN Semrock 387/15nm
- CometCIEF processed
- 10 frames each 12x300s=1h, totalling 10 hours in 11 hours observing time, starting 2019-01-11 16:10 UTC and ending 2019-01-12 03:10 UTC

Image 2) Exposures with CN Semrock 387/15nm
- 38x300s=190min bin2x2 1,68"/px
- Starting 2019-01-11 23:55 UTC 

Image 3) Exposures with Astrodon R
- 25x30s bin2x2 1,68"/px
- Starting 2019-01-11 15:35 UTC 


More similar observations
Additional information
  • Observation target
    • Comet
  • Name of the observation target
    • 46P/Wirtanen
    • Keskitaso
  • Tail length
  • 3 arc minutes
  • Coma diameter
  • 30 kaariminuuttia
  • Weather
    • 0C
  • Title for the comet
    • Binocular comet
Technical information

305mm/1200mm F4 Newton - TS2Korrr 0,75x F2.9 coma corrector/reducer => 906mm focal length. QSI690wsg ccd camera (Sony ICX814). Semrock 387nm/15nm filter. Astrodon G2 E-series RGB Filters. Hutech IDAS LPS-P2, Light pollution / Continuum filter. iOptron CEM60 mount. FoV 47'x 38'.

Comments: 2 pcs
Rauno Päivinen - 15.1.2019 at 06.05 Report this

Erittäin hieno lopputulos, animaatiosta näkee hyvin tuon komeetan pyörimisen ja spiraalimaisen rakenteen ytimen ympärillä

Jorma Ryske - 20.1.2019 at 19.59 Report this

Kiitos Rauno. Tuo kaasuspiraalin koostumus onkin mielenkiintoinen, se koostuu CN syaaniradikaalikaasusta, joka on peräisin komeetan jäisen pinnan HCN vetysyanidimolekyyleistä, jotka auringon lämpösäteily on siitä ensin sublimoinut ja sitten UV-säteily ionisoinut. Tai joku tuontapainen lämpö- ja valokemiallinen reaktio siinä on tutkijoiden mukaan taustalla.

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