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Observation by Alan Snook: Comet 46P Wirtanen

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Alan Snook


Alan Snook


2018 Dec 07 - 21:00


2018 Dec 08 - 12:00


46P Wirtanen

  • 50cm f4.1 Dobsonian
  • 17mm Ethos eyepiece x 120

East Kent

Target name

Comet 46P Wirtanen


Comet 46P Wirtanen

About this image

The instant I got my first look at Wirtanen I thought “green”. The drawing shows its position at 21.00, the cross marks where it was at 20.00. This reveals it is speeding NNE at about 7 arcmins an hour. There is a lopsided teardrop-shaped halo extending EW. The size of the halo is difficult to be precise about because it is low-surface-brightness and fades away to the sky background. I estimate its long axis to be 8 or 9 arcmins. Within the halo is a broad fan-shaped coma extending E from a bright non-stellar nucleus. The fan coma is only marginally brighter than the halo, very subtle.  

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