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Observation by Chris Hooker: Mercury in IR, 20th July 2021

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Chris Hooker


Chris Hooker


2021 Jul 20 - 06:40


2021 Jul 21 - 18:48



  • 254 mm Newtonian
  • 5x IR Barlow lens
  • 610 nm long-pass and 850 nm short-pass filters
  • ZWO ASI174MM mono camera

0.3 msec @ F/31


Didcot, Oxfordshire

Target name



Mercury in IR, 20th July 2021

About this image

An early session to capture Mercury in good seeing, curtailed by cloud (and the need to leave for work!). For this image I used a wider spectral region (between 610 nm and 850 nm) than for the previous sessions, in order to have more signal and use shorter exposures (300 microseconds instead of 500). Only eight video sequences were recorded before the cloud intervened; with more data I believe the image quality would be better. However, this data was good enough to process and stack entirely in software, without the need for manual frame selection.

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