Visual Tracking of the ISS

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This article describes my very first attempts to visually track the International Space Station (ISS) using my MEADE ET-90 telescope. The objectives are:

  1. To succeed with autonomous tracking of the ISS
  2. To capture it on video

There are many technological challenges involved in this endeavor:

Visible passes occur shortly after sunset and it may be difficult to align the ETX-90 with adequate accuracy and precision (Good alignment requires stars). Alternatively, a morning pass just before sunrise could be tried. There is also a dilemma wrt. magnification. To see structure you want to use high magnification but the higher the magnification the more difficult tracking becomes since the field of view is reduced.
I only have cheap video and photo equipment and it may turn out to be impossible to do a proper recording. For example autofocus and thing like that may ruin the capture when the object is a fuzzy spacecraft moving in and out of the field. A potential solution could be to use the video function of my photo camera because once it doesn't adjust anything while recording.
Experiment time
Visible passes do not occur all the time and clear skies in Denmark are rare so experiment time will be very limited.

12 May 2009: First successful sighting with ETX-90

There was a good visual pass between 22:41 and 22:45 local time. It was the first time I decided to attempt tracking with ETX-90. I used the 26mm eyepiece giving 34x magnification.

Since there was no time to align the telescope, tracking was done manually. The sky was quite dark (sunset occurred at 21:05) and the ISS very bright. I managed to catch the ISS in the eyepiece and follow it for several minutes – even until it wasn't visible to the naked eye anymore. While tracking, I lost it several times but it was relatively easy to catch it again. I also attempted to track using the motor drive and it is possible to use it by selecting the proper speed.

TODO: 26mm / 34x wasn't enough to clearly see structure. I suppose I'll need at least 100x. That would be a 9mm eyeppiece FOV: ???

TODO: Required tracking speed is always less than 1° / sec (details to be specified)