Embedded Files
Capturing the
Space Station
It's a star? it's a planet?
It's a star? it's a planet?
No! it's the ISS!
No! it's the ISS!
I consider it my good fortune that I got to spend most of my pre-employment life in small towns. Be it my hometown or my University in Trichy, the clear night sky was always accessible, barring the monsoon season. We had a big terrace on our apartment building, my parents would often take me and my brother to the terrace for a walk, or just to sit and stargaze. We were told: If it doesn’t move with respect to other stars, it’s a star. If it moves slowly, while other stars are stationary, it’s a planet and if it shoots across the sky very quickly, there is a good chance that you are looking at the sunlight reflecting from the solar panel array of a satellite.
We would often sit there and try to spot a satellite, the one who spotted the most "moving lights" would win. And we didn’t have an airport in our town, so the finding a plane flying over was a rarity. I always wondered, if I were to get a big enough telescope, would it be possible for me to photograph a satellite? Will I be able to tell which country it belonged to?
As I grew up, space and astronomy went on the back burner. But then I came across a YouTuber, SmarterEveryday, who were trying to photograph ISS transit in front of the sun, during a solar eclipse. And so I my interest grew.
I was on the lookout for a nearest transit, but I it to align it with my off-days schedule, so it was a bit more challenging than usual. Unlike Dustin in this video, I was aiming for a solar eclipse day, because those odds would be "Astronomical" :)
Spotting the ISS at night is easy, there is an app which will send you a notification every time the station is about to pass over your head.
The real challenge is seeing it in the daylight. Because then, one of the only ways to see a small dot in the bight sky is when it passes right in front of the sun.
But if one has the right equipment, what are the odds? Well let's see: I am currently in Mumbai, lets check for the ISS Sun transits in the 200 kilometer radius, for the entire month of December. The Red bands are the only places where one can see the transit.!
And above are the details of my closest transit:
Angular size, 47.95" and duration 0.77s !!
Check out: Transit-Finder
All ISS Sun transit for December. Circle Radius: 200 kms. Location: Mumbai.
After months of checking for the transit, it was 4th March 2020, when I finally found a very close transit prediction.5th Mar 2020, just 10kms away from my home in Mumbai. And so we got into action. Moreover 5th was my day off!
I would be lying if I said it was an easy task. I didn’t have any solar filter. So pointing the camera directly at the sun, waiting for the transit and recording a video or burst shooting photos would be like using a magnifying glass to burn a hole in the camera sensor. Another challenge was the transit duration. It was 0.65 seconds! There is no way we could even see the ISS if it was not directly in front of the sun, so all we had was a fraction of a second.
Step-1 : Setting up the camera
I slapped on all the ND Filters I had, and tried to check of it was even possible to photograph the sun safely. Moreover, my Canon Lens was an entry level model, so it had no focus distance window. Setting it on infinity was a task! I tried on a distant building and then used a pencil to mark the infinity setting on the focus ring and lens body.
(ND Filters or Neutral Density Filters are just dark filters that inhibit all light frequencies, and are useful for long exposure shots. They come in different darkness levels).
Step-2 : Risk-benefit analysis.
How long can we possibly expose the senor before it starts burning?
Every above-entry level camera has a indentation mark on the body to indicate the plane of the sensor. I set the lens at infinity and then measured the distance from the lens front to the indentation.
I then removed the lens and tried putting my hand instead of the camera, and see how many seconds it takes before my palm starts feeling the heat. With all the ND filters, this was about 8 seconds. So we had to keep the total lens-cap-open to lens-cap-close time below 8 seconds.
Step-3 : Syncing the clock!
We could not afford to have our clocks off by more than a couple of seconds. And so instead of trusting the network synced time on my phone, I went to check NIST's time server at time.nist.gov. and used the time from there.
Step-4 : Travel and Camp
With the gear ready, and while trying to find excuses I can later give myself if I destroy the camera sensor, we went to the transit site. The best spot we could find was a empty patch of land near a busy highway. We could not simply set up the camera and wait for the time to come, because the sun, moves! and it might end up going outside the frame, so it had to be checked every 2-3 minutes. Lens cap to the rescue.
That's my brother Abhang Mehendale in the frame.
Step 5 : Burst mode ON, straight for 7 seconds. 250mm, f/32, Shutter 1/3200, ISO-200.
Photos taken - 110
Photos with ISS - 2 (see if you can spot it!)
Report abuse