It’s strange how you get ideas for an AP target. I was scrolling through my Twitter astro feed and i saw a tweet saying an ISS pass would happen at about 8.45pm that evening for me. Before seeing it I’d been musing on whether the night would provide an opportunity to capture the meeting of Venus with the Pleiades. I’d read about in Astronomy Now magazine, but whilst the M45 and Venus would be closest on the 2nd and 3rd March, the weather forecast looked bad. Could it be possible to get a decent shot on that night while the skies were clear? And better than that, would the ISS pass be anywhere nearby to make an even better shot?
Stellarium, my favourite planetarium app, was the way to find out. I knew that the best chance would occur if i fitted the 0.8x reducer to my GT81 scope, so I dialled up the coming evening and placed a red viewing frame to show the field of view with GT81, reducer and Canon 700D. Setting the app to show the ISS’s track revealed that a close encounter was, in theory at least, achievable with the EOS’s view.
One of the things I have learned about getting successful captures of transient events like ISS passes is that preparation is key. The scope went outside an hour ahead of time as the sun was just touching the horizon, and its life-support of cabling was laid out running from my back door onto a small patio area. The spot is where our recycling and rubbish bins live; who says astro is not glamorous! So, batteries charged, tick. Laptop recycle bin emptied, tick. DSLR memory cleared, tick. As Venus was already clearly visible 40 degrees up it was time to see if the field of view predicted by Stellarium panned out in reality.
Using the HEQ5‘s handset, I placed the blazing planet in the lower right of the frame. I could just see an inkling of a star from M45 on the laptop’s Liveview screen. A few adjustments to rotate the DSLR left me with my best guess of matching the path of the ISS, if it turned up cue. Finally I reminded myself how to start and stop a video capture on the DSLR – not a button I use often – and checked that I could download the file to the laptop.
The family showed an interest at this point, less because they were interested in me forcing an ISS viewing for the nth time, but instead because they saw an opportunity to shout something out during my recording. The kids thought the idea hilarious and for a second I sensed my opportunity slipping. Strong encouragement was given and they retired indoors.
Before I knew it transit time had arrived. A fainter than normal ISS started approaching from the west, low in the thicker air and with a yellow tint. I started the DSLR video (banana skin number 23 averted), grabbed my iPhone and started a handheld capture as it progressed higher and left towards Venus.
For a moment it looked like the ISS was going to sail to the left of the goalpost, but miraculously (or perhaps via the laws of physics) the station cruised straight into my GT81 and DSLR’s frame, exactly like Stellarium had predicted!
I felt a rush of satisfaction. Everything had come together and now all I had to do was post it all together into an amazing YouTube video for my channel! It would go viral and I would become rich! Please click the link to see how it worked out. Spoiler: I’m not rich yet but that’s just fine.
What was left to do? Well I used the PIPP tool to extract each file from the video, and then used the Startrails freeware to make an image of the ISS’ path.
It had been an exciting few hours of astro!
Key lessons:
Don’t miss a good viewing opportunity even if the event is forecast to be at it’s best in a day or two.
Prepare your kit and practice in advance.
Think through which combination of scope and camera will provide the best capture, and check the fields in a planetarium app.
