Saturday, June 2, 2012

Venus revealed: T-3days

This morning I took a couple more images of the sun to verify exposure conditions and then thought about Venus, unseen in the glare of the Sun, racing towards her date.  But is she really unseen?  

I checked planetarium software and it shows Venus is currently about 5 degrees away from the Sun.  The field of view of my camera with 200mm and 2x telextender is about half that in the long direction so in theory the Sun should be outside the field.  Could a picture be had?

Keeping the solar filter on ... I slewed to the position of Venus and verified that no part of the Sun was visible in the frame.  Then off with the filter and took an exposure series all the way to 1/4000 which is the limit of the T2i.  Focus was kept the same as when I was imaging the Sun so if Venus was in the frame I should see it.  In the glare of daytime I couldn't see anything on the camera back but once inside I could see Venus quite clearly in the fast exposure frames. 

Three days before "new" Venus

Since we are only 3 days before transit when Venus will be directly between Earth and Sun only a slight sliver of a crescent is visible.  Pretty neat!  

Tomorrow, exactly 24hrs after this image Venus will be 3.75 degrees from the Sun.  The apparent motion is now about 1.75 deg/day (about 3.5 moon diameters).  With care it might be possible to get another picture tomorrow morning.  After that it will be too close and lost in the glare of the Sun ... at least for my gear.  Still it is pretty neat to see her one last time before she reappears against the disk of the Sun on Tuesday afternoon.

Taken in my backyard in San Jose, CA  Jun 2, 2012 10:30am PST
Canon T2i (stock), Canon EF 200mm f/2.8L + Extender EF 2X III @ f8

AP900 mount
1/2500 sec exposure @ ISO100
post-processed in Lightroom 4

1 comment:

  1. Cool! It was worth a shot and it turned out. Good thinking.