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Observation by David Davies: The Siamese Twins

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David Davies


David Davies


2018 May 07 - 23:51


2021 May 04 - 11:59



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Field centre

RA: 12h36m
Dec: +11°13'
Position angle: +0°26'

Field size

0°22' × 0°16'

  • 8-inch Ritchey-Chretien telescope
  • QSI 583 camera
  • SX Lodestar guide camera
  • Skywatcher EQ6 mount

20 x 10-minutes Luminance, 10 X 10-minutes each RGB


Cambridge, UK

Target name

The Siamese Twins


The Siamese Twins

About this image

At the beginning of May 2018, I spent several evenings gathering data on the Siamese Twins, NGC 4567 and 4568. Realising how faint the objects were, I opted for 10-minute exposures which, unfortunately, challenged the tracking performance of my, then EQ6 mount, and virtually guaranteed that I had a satellite trail on every sub. After calibrating the data, I decided not to process them since I considered that they just weren't good enough. I then ran out of dark skies and forgot about this unfinished project. 

I was reminded of the Twins by Callum Potter's recent BAA Deep Sky Notes and went back to revisit the data that I gathered in 2018. By applying some new image processing techniques, I've been able to use the data I gathered, complete with satellite trails, though I confess they have challenged my cloning skills. 

This is a crop from the original image, which presents the Twins better but at the expense of losing NGC 4564 from the top of the image.  The galaxy at the bottom of the image is an edge-on spiral galaxy IC 3578 at mag 15. Between it and NGC 4568 is the very faint (mag 18.2) PGC042075. There are many other faint galaxies in this image.

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