Below is the text of an email from my friend that explains much of what he is planning. The new collar has removed the vibration issue:
"I am using a very sophisticated piece of OS X shareware called “Solar Eclipse Maestro” to control the cameras:
http://xjubier.free.fr/en/site_pages/solar_eclipses/Solar_Eclipse_Maestro_Photography_Software.htmlThis software, which Xavier Jubier has been working on since the OS 9 days, is pretty much the defacto tool for eclipse photography, especially with Nikon cameras.
The software supports direct camera control via scripts, and the scripts are referenced to notable eclipse times (like “C2”, when the moon first fully eclipses the sun). Since these events are strongly influenced by your location, the software gets accurate time and location information from Bluetooth or USB GPSs. This way, you can write scripts to do the imaging without having to worry too much about where you will be viewing the eclipse from.
In my case, I will be scripting 3 cameras:
1) The D5100, which will be used as a time-lapse movie camera. I need the script to ramp both the exposure and the FPS rate as totality approaches.
2) The D7200, which will be my primary camera for taking solar close-ups. The script will take exposures every few minutes before totality, to capture the partial phases, and then take big bursts of images at a huge range of exposures from right before totality to right after, and then go back to taking partial phase iamges
3) The D800E, which will be used as a landscape camera, taking images every few minutes and then multiple images at totality at different exposures.
I also have another D800E, which will have a 35mm lens on it, and I am going to shoot that manually, for backup and panoramas.
Since we finally had a clear night, I tested the new camera mount tonight. I think it is working about as well as I could expect.
Here is a 1/8 second at f/8 moon shot:
I don’t think there is any vibration-induced blur at all. Any residual unsharpness is unavoidable atmospheric distortion, lens unsharpness, and diffraction.
The camera and lens are supported in 3 places. I had to shim the front lens mount and the camera mount to get everything in line.
Note the chunk of steel glued to the front for balance."
In a later post he says:
"Yes, SEM is quite an impressive program. There are lots of features I won’t be using, which are used by professional astronomers.
I worked on the tracker a bit more today. I thought of a way to take some of the error out of the alignment, and I am testing it now. So far, I’ve been able to keep the sun in the frame for around 2 hours, which is good enough for me. I’m also testing the focus drift with temperature. Seems OK, but I need to do it again in the morning, so I can get more heating.
USB camera control is pretty much an afterthought on most DSLRs. The D5100 is particularly bad - the interface won’t accept another command until the first one is processed, including being written to SD.
You can do long bursts, because that is considered one command, but there is a limit to how many frames (100). If the burst was unlimited, I would use it. But, I don’t want to take 100-shot bursts, and then have to wait and take another 100-shot burst. That gap would be annoying. "
