Observation by David Arditti: Pelican Nebula IC 5070

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David Arditti


David Arditti


2018 Sep 03 - 02:34


2018 Sep 03 - 20:49



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Field centre

RA: 20h51m
Dec: +44°08'
Position angle: +2°42'

Field size

1°20' × 0°59'

  • 81mm William Optics triplet refractor
  • 0.8x focal reducer
  • CLS and 6nm H alpha filters
  • Artemis 285 mono CCD camera
  • Astro-Physics 1200GTO mount unguided

32x2 mins CLS, 12x5 mins H alpha


Edgware, Middlesex, UK

Target name

IC 5070


Pelican Nebula IC 5070

About this image

This is not a true-colour image, but a combination of frames taken through a greenish light-pollution filter and a red Hydrogen alpha filter (6nm bandpass) on the nights of 2018 September 1/2 and 2/3. Total exposure was  2 hours 4 min. The CLS was used as luminosity on a red H alpha image. I may add some more data taken through other filters on future nights.

Conditions were poor, with moonlight, and high cloud in addition on the 3rd. It's interesting how effective the 6nm filter is in countering even these conditions, in which the naked-eye limiting magnitude was perhaps  3.0. The CLS filter is probably of little effect now against the local light pollution, which is primarily white. I may do tests comparing results to that of an L filter. A problem I found was that the filters, from different manufacturers, have quite different focus points. Of course one can re-focus, but that also changes the image scale slightly, because of the focal reducer. This means much adjustment is needed in processing.

The camera is an Artemis 285 mono camera that I've had for 12 years. I have to keep a Windows XP computer to run it, as it doesn't work with more recent Windows versions.

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