Jim Hammond's ISS

14 October 2019

You can do this!

I've seen few photos of the Space Station taken with affordable gear before. This one is fantastic.

Jim Hammond took this shot from his driveway in Oregon in the USA (yeah, I rarely post photos from outside of Oz).

Jim's rig is a Sky-Watcher 102mm Maksutov on an EQ2 mount (www.opticscentral.com.au/skywatcher-102mm-eq-maksutov-cassegrain-telescope.html). The Mak has a mylar sun filter (like www.opticscentral.com.au/skywatcher-127mm-solar-filter-for-maksutov-cassegrain-telescopes.html), and on the back was a Nikon DSLR.

Everything else was technique.

Jim knew the exact moment the ISS was going to pass in front of the sun from transit-finder.com, given his location. On the day, Jim used a watch synchronised to the Internet. For Iridium flares, I've used my GPS.

Jim needed a really fast shot or the image would blur. Experience suggested 1/1000s at ISO 400, but that depends on your scope.

On continuous shooting, Jim's camera takes about five frames per second. People can use video mode on their DSLRs, but this takes extra practice as you don't have the same control over the exposure time.

Finding the sun isn't easy with a scope. I look at the shape of the shadow of the scope on the ground. Jim uses his red-dot finder as a sight. When it's close, he slews around until he sees the sun in the camera's live view.

Next, focus is critical to the success of the shot. Jim used live view and took a series of test shots before the transit.

If you're using a go-to mount, or even (like Jim does) a simple equatorial mount with a drive, set it to track the sun. In the final moments you don't want to be slewing!

All preparation finished, it was game on. Three seconds before the transit, he pressed the button and shot until the pass was safely over - about five seconds. Looking at the shots, he'd nailed four exposures.

It's a fantastic shot, reward for careful preparation, and proof again that you don't need high end kit to get a great shot. Well done Jim!