I just wanted to chime in here on the mirror discussions. Maybe I am missing something, but I have taken images of 2 eclipses (2001 and 2002) with FILM SLR cameras an I never had a problem with shake from the mirror. It just did not seem to be an issue even with my long exposures to get full corona. I was using 200 speed slide film and had corona exposures up to 1/2 second long and mirror vibration was just not an issue. So, I understand wanting to discuss it and be sure you understand it, but speaking from direct experience, it was just not an issue for my eclipse photography. I have read about everything that Fred Espenak has written on eclipse photography and I just don't remember him ever making a big deal about either.
There are so many other issues to worry about with eclipse photography that I have concentrated on through time and mirror vibration was just never on the list. So I find these discussions interesting.
In 2001 I was using a reasonably good quality regular camera tripod and in 2002 I was using a portable German equatorial mount.
You can see all of my photography results in my "Demystifying" threads pinned to this forum.
Film is not capable of the kind of resolution you get with digital.
But I have done extensive tests with my equipment (AT65Q 420mm focal length, Canon 700D and Nikon D5300, Losmandy GM8 mount) and it is rock solid and I definitely see blur from 1/30th of a second to longer exposures.
I will have a more extensive post about this with examples in my astrophotography column tomorrow on my blog here: