Observation by Steve Knight: International Space Station

Uploaded by

Steve Knight


Steve Knight


2021 Mar 23 - 19:20


2021 Mar 23 - 21:20



  • Skywatcher 12in Dobsonian
  • 2.5x Powermate
  • ASI174MM camera
  • 642nm bandpass filter

0.559ms, gain 310, 77%



Target name



International Space Station

About this image

My quest for a clearer image of ISS continues.  Seemed to come together tonight, moon a very helpful focussing aid.  Setting a 50% region of interest helped a lot.  Suddenly went from 60fps to 265 fps.  Despite it being hand tracked I had many frames showing it and could pick the good ones.  25 frames stacked in Autostakkert and processed in Registax.

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Chris Hooker
Chris Hooker, 2021 Mar 23 - 21:46 UTC

Very nice image, Steve, with plenty of detail and the exposure is just right. You would probably do even better with a bigger image scale, i.e. by using a 3x or maybe 5x Barlow.

Well done!


Martin Lewis
Martin Lewis, 2021 Mar 23 - 23:37 UTC

Nice capture Steve,

With these CMOS cameras the max fps is dictated by the height of the ROI rather than the width so if you select an ROI keeping the full frame width but just dropping the height you will maximise the collecting area and still get the benefit of the increased frame rate.


Steve Knight
Steve Knight, 2021 Mar 24 - 17:52 UTC

Thanks guys, wish I’d known that last night Martin, a really useful tip. I thought tonight (if clear) I’d dispense with 642nm band pass filter and replace it with IR blocking only and reduce exposure.  Maybe 5x Powermate tomorrow.

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