Tuesday, August 8, 2017

Testing Exposures and Lenses for the Solar Eclipse 2017

or... How to Fake a Solar Eclipse!

Hi, everyone!

Yesterday I got this crazy idea of how to practice for DSLR imaging (in addition to the primary imaging with the CATE Experiment).

With my Canon T3i, I wanted to practice with the HDR and intervalometer functions so that imaging would be fairly automatic during the eclipse as well as test my lenses to see what the image size of the Sun/Moon would be.

My crazy idea:
Wait until dark, place a flashlight behind a soccer ball propped up on a concrete block.
Set up the camera in the HDR/Intervalometer/P mode on a tripod so that the flashlight is "eclipsed" by the soccer ball. Then I would toss some dust up in the air between the flashlight and the soccer ball to help simulate a corona.
Then by experimenting with + or - overrides and setting the ISO to 800, I would run the camera and see what would result. By the way, I used a 2012 version of MagicLantern firmware with the camera to be able to control the HDR/Intervalometer functions and settings.

I found that it may well provide the various bracketing exposures during totality with very little attention!

Then since the Moon was full (and the skies thick with smoke from forest fires all around and a thin cloud layer) I tested the settings on it as well. It also provided with with a way to test with my zoom lens set to 250mm as well as used a 5" Celestron f/5.6 telephoto to determine the image size of the Sun/Moon since last night was a full Moon.

Telephoto Zoom set at 250 mm (tripod mounted)

Celestron 5" 750mm f/5.6 telephoto scope (tripod mounted)

So the result is that I am quite comfortable with the possibilities of good exposures!

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