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Observation by Martin Lewis: Mercury 17th July 2021

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Martin Lewis


Martin Lewis


2021 Jul 17 - 11:21


2021 Jul 20 - 22:40



  • 222mm Dobsonian
  • ASI290MM
  • 685nm Longpass filter (Baader)

St Albans, UK

Target name



Mercury 17th July 2021

About this image

My first Mercury for a while in the late morning heat last Saturday morning, when Mercury was at an altitude of 61Ā°. IR image using 685nm longpass filter.

Best 5% of the best 12 one minute videos from the session were selected using PIPP peak intensity algorithm (best 25%) then AS3 in surface rather than planet mode. Spun blurred radial mask was used to remove diffraction related edge-rind effect and reveal lots of nice limb detail. Messenger data alongside for comparison.


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