7 replies to this topic

[avarakin]

This is my 2nd TSE, the 1st one was 2017.

I will have 2 rigs taking images - WO GT81 with Canon RP and Esprit 100 with Canon SL3.

I know what I will be doing with the 1st rig - it will be bracketed intervalometer with exposures from 1/4000 to 1s.

Can't decide what to do with 2nd rig - I can also run bracketed intervalomoter or I can run 4K video with it.

This camera shoots cropped 4K video without downsampling. Nice thing about video is that I will be able to catch all BBs and I should also be able to stack many exposures, so I am leaning towards this option.

Any thoughts?

 

Alex

[dcaponeii]

I for one will be taking video with two different cooled astro-cameras using Firecapture for acquisition.  I will then split the videos into segments using AS!4's expand feature and/or limit feature to isolate specific shorter segments from the 4 min 30 sec video centered on totality.  I've got my 12" at f/5 which captures the full disk on my Orion G26 camera and a 200mm SLR lens that captures about several degrees of sky centered on the Sun.  I'll be planning to crop that for capture to a 2000 x 1500 pixel ROI with the Sun at the center.  It works out to about 4 x 3 degrees of sky but if the corona requires it then during totality I'll use the full chip of the Orion G10 camera imaging through that lens and then crop after stacking.

 

Leading up to and following totality I'm using Firecapture's auto-capture feature to take 60s videos at 10 minute intervals (20s video at 10 minute intervals for the 200 mm lens) that will become animations of the movement of the Moon's disk across the Sun.  Both yield about 1000 frames to stack for each capture time.   Weather permitting of course.

[N-1]

I captured a 4k video of the last TSE and it's now one of my greatest data treasures. It's hypnotic to watch. Single frames extracted from it are also decent. But, the dynamic range isn't great (I used a Lumix GH5), and stacking doesn't seem to add much. I did do traditional bracketed exposure series using another rig as well, so that was covered too. Glad I took the vid.

Edited by N-1, 06 April 2024 - 06:47 PM.

[dcaponeii]

I captured a 4k video of the last TSE and it's now one of my greatest data treasures. It's hypnotic to watch. Single frames extracted from it are also decent. But, the dynamic range isn't great (I used a Lumix GH5), and stacking doesn't seem to add much. I did do traditional bracketed exposure series using another rig as well, so that was covered too. Glad I took the vid.

Stacking with astro-cameras really improves the SNR.  The trick is to not use the best % of, for example, all 1000 frames, but you use the quality graph that AS!4 generates to isolate a segment of the video with good data and then use the Limit feature to isolate the stacking to within just THAT segment of the video.  Otherwise, you're getting frames spread across the entire, for example, minute of video instead of just a few seconds of video.  It take a bit of time but not a horrendous amount and even 10 frames in the stack will greatly improve your SNR.  I've used the same technique of ISS imaging and even 6 frames is far superior to a single frame.
 

[avarakin]

Thank you, dcaponeii and N-1!

What would be the recommended exposure and ISO at F5.5 for the video capture?

I am thinking about 1/4000, according to calculator for BBs.

[dcaponeii]

Thank you, dcaponeii and N-1!
What would be the recommended exposure and ISO at F5.5 for the video capture?
I am thinking about 1/4000, according to calculator for BBs.

My test captures with my G26 have been at GAIN = 200 and around 3ms exposure time.

[N-1]

I'd set it to expose for the inner corona/prominences rather than the beads. You'll still get some of the BBs, though maybe not as detailed, but there will still be a nice amount of detail during totality proper when there are no BBs, which is the much longer part. There may be some info available on what ISO gives the maximum dynamic range for your camera, and I'd stick with that.

[avarakin]

Thank you, dcaponeii and N-1!

I will probably run it on auto exposure even at the risk of not perfect exposure, given that I want to watch eclipse too.