Wednesday, June 6, 2012

Transit of Venus

Transit of Venus
©JP Parmley


I was not able to get set up for this event, but Steve was ready to go...waiting for the clouds to break long enough to get a few shots.  Below is how he got the shots and time lapse video.

First, TransitofVenus.org describes the event as "When Venus passes directly between earth and the sun, we see the distant planet as a small dot gliding slowly across the face of the sun.  Historically, this rare alignment is how we measured the size of our solar system.  The view is like a front row seat to the transit method, by which we now find planets around distant stars."   

The next time this event occurs is December 2117.  Needless to say, this is my last blog and his last pictures on this subject.

Just as in the previous post, careful attention had to be taken to ensure that neither eyes or equipment was damaged.  The set up was virtually the same except the lens was changed to a 70-200 2.8L IS. The effective 448mm set up from camera to lens was:

Zacuto Z-Finder
Canon 7D w/ remote shutter release
Tamron-F AF Tele-Converter 1.4x
Canon EF 70-200mm 1:2.8 L IS USM
Promaster UV filter 77mm
Vivitar Series 1 HD Pro NDX Variable Neutral Density Filter 77mm
Vivitar Series 1 HD Pro NDX Variable Neutral Density Filter 82mm
(The ND filters each step up the diameter of the threads (77 to 82, and 82 to 86) which make them nice for stacking and avoiding vignetting)

Pictures around 6-7pm were taken at ISO 100, f 32, 1/1000s, 200mm with both ND filters set to about 90% of maximum (~7-8 stops each).

As the sun set, the light was greatly reduced so the settings were adjusted to ISO 100, f 32, 1/50s, 200mm while both ND filters set to about 10% of maximum (~2 stops each). 

The 7D's live mode and digital zooming focus feature made the fine focusing adjustments at infinity very easy and quick.


Special thanks to Brian Davis, Chief Meteorologist, of WDTN Storm Team 2 for continuing to show our pictures on their weather segments.

There was some spare time as the sun set so Steve captured 3 minutes of video with the same setup at 1024 (30fps) and then was cropped, time compressed it to 15 seconds and then rendered it in Final Cut Pro for a NTSC format.  After the second time I watched it, I noticed something strange......do you notice it?

You can see the video here.   

Enjoy,

JP






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