July 14th, 2022, 9:48 p.m. local time
What's better than two nights of tracking the International Space Station? How about three! Well, actually this was my fourth in a row - I did not publish anything from the first night's observation.
On this evening the ISS approached Zenith (top of the sky), past the handle of The Big Dipper. I set up my DSLR camera on tripod, pointed nearly straight upwards, in the direction of Ursa Major.
For another twist this evening, I leveraged nova.astrometry.net to mark the constellations in my photograph. What is this site? From its front page:
If you have astronomical imaging of the sky with celestial coordinates you do not know—or do not trust—then Astrometry.net is for you. Input an image and we'll give you back astrometric calibration meta-data, plus lists of known objects falling inside the field of view.
So you can upload any sky picture, and the website will attempt to map the constellations, Northern or Southern Hemispheres. I used it once before, to frame the location of the meteor I captured during the Perseid Meteor Shower of 2020.
I wondered if this would really work, especially since there are significant star trails in the photo due to the nearly ninety-second exposure. The stars look like little pegs, easier to see in this larger non-annotated image:
The final annotated image was spot-on identifying the sky location, despite the star trails and despite the ISS's flight line cutting through the top of the picture. The ISS flew right between Bootes and Ursa Major, then cutting through the highest point (from my vantage) of the constellation Draco. Again on this night, the ISS was very bright, brighter than any star, possibly except Sirius, which is not visible in our Summer sky.
As a final consideration, I tweaked my camera settings a little from my prior night's DSLR ISS capture. Notable is that I used a much higher ISO, 800 instead of 100, to try to bring in more light and specifically highlight the bright ISS orbit line.
- Canon EOS Rebel SL3 on tripod
- Sigma wide field lens, 17mm focal length
- 88 sec exposure
- ISO 800
- Minor touchups in PaintShop Pro and AfterShot Pro