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ISS 25th July 2019


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About this observation
Chris Hooker
Time of observation
25/07/2019 - 22:47
International Space Station
Observing location
Didcot, Oxfordshire
254 mm Newtonian
2x Barlow lens
Celestron Skyris 445m camera
Baader IR-cut filter
0.36 msec @ F/9.6
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This stack of 50 frames from the midpoint of the ISS pass on July 25th is the best image from all of the recent series of passes that I was able to capture. The ISS was almost overhead, at a distance of 420 km, and the seeing was relatively good. The heat-rejection panels on one side are overexposed, and the shadow of the main axis of the station is being cast on the other set of panels on the left-hand side. For space geeks I have included an annotated copy of the image with some of the modules identified. To get an idea of scale, note that the Bigelow module is about 3.3 by 4 metres.

At the time of this image, the SpaceX Dragon had just been launched from Cape Canaveral. In the montage images from the 28th, in the previous posting, the bright spot of the Dragon can be seen at its berth between the Columbus and Kibo modules.


Fossil Light's picture

Wonderful sharp detail Chris- very well done. Do you boost gamma in the processing to bring out the fainter details that otherwise are swamped by the very bright areas?

Chris Hooker's picture

Thanks, Martin. I'm actually very pleased with that image, although I am still aiming to do better!

To answer your question, yes, one of the things I do is play with the gamma curve in Registax to slightly enhance the fainter areas such as the solar arrays. I also use wavelets, and a slight clip of the histogram to reduce background noise. I don't have a specific recipe because every image is different, but I have a fair idea of how much of which controls to apply.

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