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Observation by James Weightman: Spectral Comet NEOWISE (improved version...

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James Weightman


James Weightman


2020 Jul 26 - 07:21


2020 Jul 26 - 07:21

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Ursa Major

Field centre

RA: 11h49m
Dec: +38°08'
Position angle: +76°05'

Field size

4°52' × 2°26'

  • Canon 100D DSLR +100mm lens
  • Star Analyser 100 grating
  • 1.3 degree prism
  • Various stepping rings
  • Fixed tripod + tracker

20 x 20secs ISO1600


Cirencester, Glos UK

Target name

Comet C/2020 F3 NEOWISE


Spectral Comet NEOWISE (improved version)

About this image

Crude spectrum obtained by placing grating and prism in front of camera lens. (The main purpose of the prism was to centre the spectrum and thus making finding them much easier!) This image show the main components of the spectrum of the comet's head especially the bright green C2 band which often causes the greenish tinge in images. As bonus the banded spectrum of a M type star can be made out top right, later identified as SAO 62754 Mag6.5, Spec M3III.

Files associated with this observation
Like this image
Derek Robson
Derek Robson, 2021 Mar 17 - 12:36 UTC

Fantastic job.  Was the 100mm lens, the FL or dia? (i.e. what I mean is, 100 mm camera lens or 100 mm refractor?)

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