Photographing Earthshine

I generally try to avoid going back and tinkering with old photos because - as with any creative endeavour, whether it's writing a story, composing some music, or making a film - there comes a point where you have to say, "Enough's enough," and walk away from it. However, I was recently contacted by a production assistant at Popular Photography magazine saying they were interested in using my image "Crescent Moon with Earthshine" for a "How-to" feature in the June 2012 issue*.

The original image was composed back in April 2007 and close inspection shows quite a lot of noise and signs of oversharpening (as well as some obvious artefacts from where the two stacks were spliced together). I've learnt a lot about processing since then - and newer tools have become available - so I decided I could do a much better job if I went back to the source files and reprocessed them from scratch.

For those who are interested in the technical nitty-gritty, the images were taken using a Canon 350D (Rebel XT) DSLR connected to a Vixen SP-102 achromatic refractor (focal length 1000mm). Earthshine (which is the reflected sunlight from the earth illuminating the shadowed part of the moon) is easy enough to capture on camera, but normally results in a severely over-exposed crescent. To retain the detail on the crescent I shot 31 images at 1/60 sec, ISO 200, and to expose the earthshine I took 11 images at 0.5 sec, ISO 800. I then stacked and sharpened these images separately using the freeware tools AviStack and RegiStax, before combining them in Photoshop using a layer mask to create the finished version you see above.

This new "redux" version is a big improvement on the original, and is probably the best I could do given the quality (and quantity) of the original 350D image files. Some flaws are still apparent: the dark band between the earthshine and the crescent is a little distracting and the earthshine itself could be brighter. These are issues that could be fixed by capturing more images at a wider range of exposures - and then combining them using HDR software.

But that's a project for another day...

*And in case you're wondering, yes they did use it, and yes they did pay me.

See also:
Shooting the Moon: Lunar Photography with a DSLR and a Small Refractor
Earthshine (NASA Science)
Planetshine (Wikipedia)