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Observation by Robin Leadbeater: Comet 29P – a low resolution spect...

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Robin Leadbeater


Robin Leadbeater


2021 Oct 15 - 02:42


2021 Oct 17 - 14:59


29P Schwassmann-Wachmann

  • ALPY 200 spectrograph
  • ATK 314 camera
  • Celestron C11 SCT 280mm aperture f5.5

3000s (5x600s)


Wigton Cumbria

Target name

Comet 29P/Schwassmann-Wachmann


Comet 29P – a low resolution spectrum

About this image

This very low resolution (R~130) spectrum was taken ~20 days after an outburst which saw the brightness increase by ~ 6 magnitudes to an integrated brightness of ~11R

By the time of this observation the original relatively condensed coma had expanded dramatically and the corresponding reduction in surface brightness reduced the available light passing through the spectrograph slit. I therefore used my very low resolution faint object ALPY200 spectrograph. 

The spectrum is that of reflected sunlight from dust with no evidence of emission features, compared with this observation of  C/2020 R4 for example, though this colour image in the comet section archive taken five days earlier does show a hint of blue green Swan band emission.

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Like this image
Nick James
Nick James, 2021 Oct 17 - 21:58 UTC

Very impressive to get a spectrum of something this faint.

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