Today marked another opportunity to capture a transit, and this time, we had clear skies and I kept the timing straight in my head and everything. The target was the Tiangong space station, China’s own entry into low-Earth-orbit experiments and observations, and the waning crescent moon. I checked everything, was on location (several kilometers south of Walkabout Estates Plus,) did my focusing and exposure tests, and was ready to go with the high-speed shutter setting when the time came.
And it did indeed work:
My timing was actually bang on, since I caught the space station on approach and completely past, as this animated gif (pronounced, “em-pee-FOR”) shows clearly.
What? You didn’t see a damn thing? But it’s right there! I even made sure to travel to the location where it would pass right across the center of the moon!
All right, sheesh. Here’s an annotated version – look to the left of the yellow pointers:
Yeah, we see the problem here, that the 600mm wasn’t anywhere near the magnification necessary to show anything but a speck, especially when aiming only 34° off the horizon, meaning Tiangong was much more distant than overhead and allowing even more of the humid air between my location and the station. So it was successful, but not at all in a way that I wanted. At least I have an inkling what to attempt next time, which will likely reveal even more refinements that should have been done.
By the way, if you look at the moon you can see that it appears to travel downwards, which it is; the frames represent just over a second of actual time elapsed, and that’s how far it moved. More or less, anyway – you can also see some lateral twitching, which is either due to atmospheric distortion or twitching of the tripod, or both. The shutter speed was 1/1250 second, so fast enough to stop all but the most egregious of camera shake, but that doesn’t mean that between those frames there wasn’t a little vibration coming into play.
Still, the 2X teleconverter is probably warranted, if I don’t actually opt for the telescope instead, but I’m still working out how to get the clearest shots from that, much less have the tracking motor working properly. Still chasing this goal and not particularly close to it, is what I’m saying.
Other attempts can be found here (except for the Falcon one – I’m just linking to those posts tagged with “transit”) and the site I’m using to plot these is Transit-finder.com, which has been working well after that first attempt.