|
Hi Peter
Thanks – there is a lot to learn indeed!
The task of establishing the “perfect” system configuration (‘scope/camera) and the ideal exposure is made more difficult when you shoot at different times of the day and under varying seeing conditions. The event will span 8:15am to 2:44pm (ish), approximately a 6 ½ hour period.
Today, I had the Vixen 4” f9 refractor and the Canon 7D at prime focus even at that focal length, 918mm, there were significant variations between frames depending on the state of the seeing at the time of the exposure. I was using a full aperture Baader astro solar filter (ND38) which saw me shooting at 1/5000 sec, ISO100 and I think the blue channel might have been clipped, so I’ll experiment with 1/6400 or maybe 1/8000.
I then fitted the Canon Extender x1.4 but got an Err message – I think that I need to tape some pins on the extender as it is trying to report on a non-existent lens.
I then tried the Tak x1.6 extender but had to remove the JMI motor focus to obtain sufficient in-focus. At the end of all that, it seems that the way to go for full disc shots for me could be the Vixen ED102S, JMI motor focus, Canon extender x1.4 and Canon 7D with the Baader ND38 full aperture solar filter. There is significant light fall off at the limb.
I ran a 30 sec Canon movie and have yet to convert it to an AVI for processing in AVIStack, although it seems too much work to grab small movie segments from which to produce single stills to then combine into an overall movie.
I’ll probably just stick to taking single shots at timed intervals and try to make a movie from these and just tolerate the frame to frame variations arising from the variable seeing conditions.
I think a motorised focuser will be very useful over the long session so that focus can be periodically checked without having to touch the ‘scope. Remote Live View on the PC at x10 mag is really helpful here.
However, all this presupposes decent weather and the Sun clearing the tree tops from my back garden set up location, before 8:15am on Wed 6th June!
Cheers
Dennis
|