Tuesday, December 21, 2010

Total Eclipse of the Moon

Last night (December 20, 2010 in Colorado), there was a total eclipse of the moon.  I was watching the weather with trepidation - it had been mostly cloudy all day - and as night fell, I was pretty pessimistic about the chances for seeing anything.  But I dutifully put the telescope outside to cool, and got the camera equipment ready, just in case things cleared up:


Wonder of wonders, the sky cleared up during the eclipse.   There were clouds coming and going all evening, but nothing that diminished the enjoyment of the event.   Here is a shot of the fully eclipsed moon north of Orion, with Taurus and the Pleiades in the shot (and some tree branches in the foreground).  A cloud, illuminated by Fort Collins city lights, drifts in front of Orion.  This was taken with at 18mm focal length on a Canon EOS 40D (1.6x crop factor):


Switching lenses, here is a shot at 100mm focal length on the same camera:



But the real exciting shots were taken through the telescope  a Meade LX90-ACF 8", with 2000mm focal length at f/10 - with my Canon 5D Mk II.  Here is a shot at totality showing how nicely the moon fills the field on this setup:


I diligently took pictures through the telescope every 15 minutes or so, and assembled the results into a collage.  Some of the technical details include:
  • Since the Meade is on an alt-azimuth mount, pictures suffer from field rotation.  So, at the end of the 3 or so hours, the moon had rotated by just over 90 degrees in the camera.
  • This means each image had to be rotated by a small amount more than the previous one to be oriented in the proper direction.  I used the EXIF data from the camera to find the exact time of each shot, so I could calculate the rotation.
  • The collage was assembled in Adobe Illustrator, which allowed good control of orientation and position
  • Each shot is taken with a somewhat different ISO rating (between 100 and 6400) and shutter speed (between 1/50 second and 2 or so seconds) but I kept brightness adjustments to a minimum in the collage
  • The moon was obscured by haze during the partial phases - both entering and exiting - but the telescope cuts through that pretty nicely.  The sky was pretty clear during totality
Without further ado - the full products of my labor:


And now, time for some more coffee...

3 comments:

Brian said...

Very nice. Clouds cut us off just before totality here in San Antonio TX so I'm delighted to see the whole event.

Any chance of a "Wall Paper" sized image for my desktop?

Thanks,

Brian

Ross Cunniff said...

Thanks! You can download a higher-res version at flickr.com

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