Apr 13

ISS near Venus flyby (low magnification experiment)



I have noticed a few weeks earlier that around this time there will be a few favourable International Space Station close flyby passes to planet Venus. The fact that Venus just past greatest elongation (when it is at the greatest separation from Sun from our point of view) and the Space Station crosses the sky from my location during daytime offers a possibility to capture this rare event again.

(So far I only had one good opportunity for ISS near Venus flyby in September 2017, more information here)

Due to the covid-19 situation I do not go away from home, despite these events are very tempting. Ideally if possible I would travel to a favourable location to be on the centerline, but not these days. So this time I used my small refractor to get wide enough field of view to squeeze in the whole event.



As always for the most accurate flyby forecast I visited Calsky, on which a forecast looks like this. It shows all the important details I need to know for the appropriate preparations.


My near pass was forecasted at 15:25 BST/14:25UT in the afternoon. Interestingly yesterday 2 hours earlier I had an almost identical flyby visible from home, sadly clouds ruined the fun. Not today, sky nicely cleared, although it remained windy after what happened yesterday, it felt inappropriate to complain for some wind (lol).  The small refractor telescope performed excellently, despite its small size it over punches over its weight constantly. Love it!

Usually when sky is nice and clear, I can find Venus by naked eye, it only takes patience. But today I had some clouds still lingering around, so instead of naked eye I used solar filters (for scope and for finder scope too) to find Sun first. Once that was done, checked the Sky Safari app how far apart Venus was from Sun in degrees and by using the mount’s setting circles I simply moved the scope with the hand controller. When I could spot Venus in the finder scope, the rest of the task became much easier.




Skywatcher 72/420 ED Apo refractor telescope
Zwo ASI174MM colour camera
Skywatcher Allview mount
Baader IR-Pass filter



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