Sunday, July 23, 2017

International Space Station


Another local overflight of the International Space Station (ISS) gave me the opportunity to refine the exposure for the photoshoot following last year’s attempt.  The photos were taken handheld on a Canon 70D at 600mm (960mm equivalent) with a 1/800, f/7.1 exposure at ISO 1600.  I experimented a bit with exposure but quickly returned to the planned exposure.  

More important than the camera’s technical settings is a comfortable chair in which one can lie back with at least one elbow supported on an arm rest while panning the quickly moving station.  My chair was the low-slung collapsible kind one sees at lawn concerts. 

The other main trick of the trade includes focusing at infinity.  For this I arrived a half hour before the appointed appearance of the ISS, placed the camera on a tripod and focused upon Jupiter, making it as crisp as possible.  The image of Jupiter below is a 100% crop from the Lightroom loupe, zoomed to 11:1.  Obviously, I did not see this in the camera’s LCD panel, I only saw a small disk which I made as small as possible with the focusing ring.  To ensure that the zoom and focusing rings did not “drift” during the shoot, I taped them down with painter’s tape which does not leave an adhesive residue upon removal. 



The panning was done with Raw files – I did not follow my own guidelines, I should have used JPEGs to increase the camera’s burst rate.  Well... that’s life.  Between bursts I tried keeping the ISS in the viewfinder so I wouldn’t have to spend precious seconds re-aiming the camera.  When near the horizon, approaching or receding from the camera, the ISS image is faint, increasing the difficulty of aiming the camera.  After the shoot came post-production: selecting the best of 300 shots, cropping, resizing and arranging them in the gallery. 

The image below has been resized, eliminating the view of pixels as seen In the Jupiter image and smoothing the color gradation from pixel to pixel.  The original ISS image is about 40 pixels wide; for comparison, the image of Jupiter above is about 30 pixels across. 

Enjoy!