[ATMoB-discuss] Images of last night's ISS/Shuttle pass...

[John Boudreau]

Here's a few images from my webcam video from last night's ISS/STS-117 pass. The top row is the ISS and  from L to R, at 3 stages in it's pass ranging from about 40° altitude to near the zenith. The single image of Atlantis below is from two frames taken shortly after passing near the zenith:

http://home.comcast.net/~jeboud/satellites.htm

Throughout most of the video, most of the time the ISS was brighter than the Shuttle. As both neared their maximum altitude and headed towards the SW, I was tracking on the Shuttle and couldn't put the scope back on the ISS when it was at it's brightest due to interference from the RA motor of my G11 mount. So the shuttle was recorded at or near max magnitude, but the ISS was not.

I used a TEC 140 refractor at 980mm focal length (f/7) and a Philips ToUcam 840 webcam. I hand guided the scope using a Telrad as the 'gun sight'. I simply moved the scope in jumps a bit ahead of the spacecraft, and stopped momentarily as each traveled through the center of the Telrad 'bulls eye'--- and (hopefully) FOV of the camera. With this method, orbital motion blur was held to a minimum by the 1/1000 second exposure setting I was using.

As for the Heaven's Above satellite website claim that the Shuttle was in the lead:
My NW was pretty clear, and I had been watching for one of the craft to appear rising out of the trees... first object I saw, I started the video and put the scope on it repeatedly (it couldn't be held steady--- I had to use the 'jumping' method described above). As the object was about 45 or 50° up, I noticed a fainter companion behind it and then targeted that for a few moments--- then back to the brighter leading object. I went back and forth between objects for a few times, and after being on the latter object for a bit again, went to try to center the leader once more--- but ran into RA motor clearance problems with my Losmandy G11 and couldn't follow  either target anymore. In the video, the first object shown for quite a while is the ISS, then the Shuttle appears about halfway through---- then they alternate appearances, finishing with the Shuttle. With all the hectic goings-on I was dealing with following the objects with a 980mm focal length *by hand* and between clouds, I can't I can't claim 100%  **for sure** that I didn't get mixed up: but watching the video moments after the live event, the sequence of ISS... then Shuttle was consistent with my originally targeting the brighter lead... then the somewhat fainter trailing object. I can't see how I could have confused the two, but I suppose anything's possible.

At least they're easily identifiable on the video ;o)

---John