Tuesday 3 May 2016

International Space Station transiting our Sun

I have been planning this for some time now, but somehow did not have any luck with Sun and ISS these days. Today the predicted transit was about to happen at 12:35:28 from Wimbledon, United Kingdom.


The weather was splendid till about noon, when suddenly clouds began roll in, luckily scattered ones so looked like a good 50-50% success-fail ratio. Well just about 20 seconds after the transit, thin clouds obscured the Sun, but I was already very very happy by then :)

Prediction and details

I have used ISS Transit Prediction app, but wasn't 100% accurate (again), it gives an amazing estimate but to be fully sure about the exact path through the disk of Sun, I would recommend to use CalSky. Here is what the website said:

Centerline for the transit

CalSky shows the actual sunspots too, which helps to identify where ISS will enter and exit the disk of Sun


The usual Skywatcher 127/1500 maksutov was my main tool to capture the transit of ISS (with a Zwo ASI 120 MC color camera), but for the second time the 0.5x focal reducer was a huge help, I could squeeze a 50-60% the disk of Sun in my FOV. The only mistake I made is that I didn't check CalSky, only the ISS Transit Prediction app and the expected path through Sun was slightly off from my expectations. 

According to the app and my basic calculations, ISS should have gone through sunspot region 2536 and 2535, but ISS entered the disk above 2536 so missed a few frames sadly.
Conclusion: Always check CalSky.....

Final result

Animation of the 15 frames containing ISS

Photo in original:

1 comment:

  1. Always check CalSky ... and consider being a supporter! I use CalSky all the time. They have an option to send some money on a regular basis, and giving my frequency of use, I decided to subscribe. Even got my name on the "local supporter" screen!