Sunday, July 23, 2017

Round Two - The Eclipse

My plan has evolved to since the first beta I did a couple of weeks ago (Beta test).

After trying several different mounts, including Celestron's Heavy Duty Tripod, I have settled on a mount that I already have, the Explore Scientific Twilight I.  I was trying to use a lighter duty mount as I am flying to the location but I could not find one that has the fine adjustment that this one has.  It breaks down to about 29.5 inches which is only 4 inches longer than my camera tripod.

Main EquipmentBackyard EOS (BYE)
Orion ST80 80mm Refractor
Canon T3i/600D
Explore Scientific Twilight I
Mylar Solar Filter
Adapter - T-adapter for Canon cameras to telescopes
Computer - HP Envy
Computer Shade - LapDome

I also tested the time it took to complete a six frame capture plan and a four frame capture plan with my equipment.

Results are as follows:

6 frames download to the computer
- exposure 1/2000, 1/200, 1/20, 1/8, 1/4, 1
- 46 sec to complete the circuit and download to the computer

6 frames download to the camera
- exposure 1/2000, 1/200, 1/20, 1/8, 1/4, 1
- 28 sec to complete the circuit

4 frames download to the camera
- exposure 1/2000, 1/200, 1/20, 1/2
- 18 sec to complete the circuit

Based on the results, I will use the four frame capture plan and download to the camera only since it is the faster than downloading to the computer.  It is possible to get much faster frame capture (up to 3 frames per second) using a serial cable in addition to the USB cable with certain eclipse capture software as described by Jerry Lodriguss (Catching the Light).  I actually purchased one of these cables from Hap Griffin (Imaginginfinity), however, I don't want to pay for and learn a new program at this point and my computer does not have a serial port anyway (although I probably could use an adapter).

Using BYE I will set the 4-frame exposure plan to loop (repeat) a couple of minutes prior to totality and continue until after totality.  Since I am using a fixed frame, I decided to cut out the 1 second exposure which would have been affected most by Earth's rotation.  If I were using a lower focal length lens/telescope the rotation problem would be less.

We are going to Bowling Green, KY or Nashville, TN to witness this event so we will have at least 1 minute of totality.  Using my capture plan I will have a minimum of 5 frames per exposure during totality.  I hope some the just before and just after frames pick up something cool.  Also, it is very important to have a quick release filter for your lens or telescope.

Also, Fred Espenak, aka Mr. Eclipse, has great advice on how to take pictures of the eclipse, How to Photograph an Eclipse.

Most Important
I plan to watch the eclipse which is why I am doing all this to automate the imaging.  It is going to either work or not.  I will set all this all up press the button to start the sequence, check finder scope once or twice to make sure the sun is in the center of the FOV, and that is it.  If a don't get anything, oh well, if I do, it is icing on the cake!

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