Visual Tracking of the ISS
This article describes my very first attempts to visually track the International Space Station (ISS) using my MEADE ET-90 telescope. The objectives are:
- To succeed with autonomous tracking of the ISS
- 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)