ISS sightings (trails)

2016-07-28

Yesterday evening I was looking out of the window, at about 22:45. I saw a bright light flying slowly from south to north. Must be an airplane, was my first thought. But no, it wasn’t blinking. Being too bright for a regular satellite, it might be the ISS1 then. I even tried to take a snapshot, but it passed too fast and disappeared behind the horizon.

Maybe it would reappear later and I could photograph it then, I thought. Knowing that the ISS takes roughly 90 minutes for one revolution around the earth, I knew I had some time to research and prepare.

So, I checked on calsky.com’s daily astronomy calendar2 and yes the ISS should be visible this night, even five times.

The times were enlisted there but I also wanted to know where it would appear.

A quick Google search for “iss fotografieren” lead me to an article3 about the topic, which in turn lead me to heavens-above.com4 website.

Visible transits can be nicely plotted there for the current time and entered location. To get a better orientation I compared the trajectory with constellations in stellarium5. To my surprise the next transit, at 1:19am followed a somewhat different trajectory. Instead of SW-NE it went more WNW-ENE, also staying lower on the horizon.

I also decided that a trail photo was the only meaningful thing to try with my given equipment.

ISS partial trail
ISS partial trail
Info Button
Foto Information (EXIF)
Exposure: 60.0s
Aperture: f/3.5
ISO: ISO 160
Focal length: 14mm
Date/Time: 2016:07:28 00:28:46
Make: OLYMPUS IMAGING CORP.
Model: E-P1
Software: Rawstudio 2.1-20160428-983bda1

Well, I forgot how hard it is to focus infinity at night with this AF objective that has no mechanical end stop. And so I almost missed it and only got a rushed half of the trajectory.

The ISS was travelling from left to right on this image.

Afterwards, I checked the manual and camera menu and found an entry that let the cam focus on infinity after turning on. It was actually enabled. Camera: Olympus PEN E-P1.

ISS partial trail, increased contrast and exposure
ISS partial trail, increased contrast and exposure
Info Button
Foto Information (EXIF)
Exposure: 60.0s
Aperture: f/3.5
ISO: ISO 160
Focal length: 14mm
Date/Time: 2016:07:28 00:28:46
Make: OLYMPUS IMAGING CORP.
Model: E-P1
Software: Rawstudio 2.1-20160428-983bda1

Always surprised how many stars are visible despite the city light pollution.

The trail is crossing the constellation of Perseus and above is Cassiopeia.

ISS trail 2 w/ moon and into the tree...
ISS trail 2 w/ moon and into the tree...
Info Button
Foto Information (EXIF)
Exposure: 60.0s
Aperture: f/3.5
ISO: ISO 400
Focal length: 14mm
Date/Time: 2016:07:28 02:05:26
Make: OLYMPUS IMAGING CORP.
Model: E-P1
Software: Rawstudio 2.1-20160428-983bda1

Third transit of this night, at 2:56. I misestimated the trajectory.

While the results are not that great, it was still fun and I’ll try that again.

Later I found that I actually had satellites (I think it’s a plug-in) in stellarium and could visualize the trajectories there directly. That should help for next time.


  1. The International Space Station: https://en.wikipedia.org/wiki/International_Space_Station

  2. https://www.calsky.com/ (german)

  3. http://www.heise.de/foto/meldung/Die-ISS-scharf-fotografieren-1560271.html (german)

  4. http://www.heavens-above.com

  5. Great planetarium software: http://www.stellarium.org/

Tags / Keywords: astronomy, photography
Copyright 2015, 2016 Cem Aydin