Tips needed for imaging the 2024 solar eclipse

[Moonstruck]

Hi Robin,

I would like to image the 2024 solar eclipse (in the US) on April 8, and need to learn how to do that using Sharpcap. I have never imaged an eclipse before and could really use some guidance! I will have a Skywatcher Esprit 100 scope and a ZWO asi 294 color camera. At first I thought it would be relatively simple, but the more I read about it the more complicated it is getting... for one thing I learned I will need to take off the solar filter during totality to see the "diamond ring," which requires some good timing. Also someone on cloudy nights was talking about using an automation program to automatically change the exposures to get the full dynamic range of the disk and its corona (i.e, an autoexposure program). Does Sharpcap have that, and if so, how do I use it? Is it really needed?

Also- would I take still frames (FIT) or video (SER) and stack afterwards? What is the recommended gain and exposure? If you have an eclipse tutorial already prepared specific for Sharpcap with instructions on settings, etc that would be great. I am looking for a relatively simple process that will give good results. Ideally I would like to just set it up and let it run on its own through the eclipse so I can enjoy the event with family, but since I have to time removal of the solar filter at totality it looks like I need to have some involvement during capture... if you have any info/ideas would you please let me know?

[oopfan]

I've photographed two eclipses in my lifetime: 1973 in Africa and 1991 in Mexico. If you are in the path of totality be prepared for a stunning experience that no words can express. Place a white sheet on the ground and watch what happens at the moment of totality.

I used Kodachrome slide film (a slow emulsion.) The shutter speed of my best shots ranged from 1/25 sec to 2 sec. I did go down to 1/250 sec but I'd recommend sticking with the longer exposures. This was with a 75mm f/16 refractor at prime focus (48 inches). With SharpCap you'll have the benefit of the histogram. I had a fully manual Leica camera, so I can't really help you with your settings. Just use the histogram. However, I would suggest writing scripts to automatically run through a range of exposures. Perhaps 10 frames @ 1/25 sec, 10 frames @ 1/8 sec, 10 frames @ 1/2 sec, 10 frames @ 1 sec, 10 frames @ 2 sec. With regards to Live Stacking, I don't see a need. Things change very rapidly so Live Stacking may just end up harming you. One more thing, make sure you have plenty of battery power on hand to run your mount and laptop. Since it is daylight when you set up your scope you aren't going to get accurate polar alignment, so be prepared to make corrections to recenter the image.

Brian

[admin]

Hi,

I'm afraid I can't claim to be an expert on this at all - I've never seen a total eclipse, let alone tried to image one, and anything learned from partial eclipses really isn't going to be helpful...

I expect that the advice you are picking up from Cloudy Nights is based far more in experience than anything I could suggest. What I would suggest is thinking of ways that you can test your configuration in advance (for instance you could use a cardboard mask with a number of relatively small holes to cut out most of the light to see how camera autoexposure reacts to a rapid dimming if you are taking that approach). In particular, if you are going to go for automation using the sequencer or similar then lots of pre-testing is important because it's harder for you to take over and fix things if they go wrong.

cheers,

Robin

[turfpit]

John

A search on Astrobin for 'solar eclipse' gives many pages of images. Searching through these will give you some ideas for capture. Look for the ones that are 'Image of The Day', 'Top Picks' or have many 'Likes'.

https://www.astrobin.com/search/?q=solar+eclipse

Dave

[oopfan]

You are on your own with what exposure to choose for the second-contact Diamond Ring. Like a lot of things it comes with experience with what works and what doesn't.

However, once you get past second-contact when the Diamond Ring subsides, in my opinion it is a simple matter of experimenting to find the minimum exposure and maximum exposure that pleases you and your kit. That should take no more than 15 seconds to complete. Then I suggest running a script that you will write that takes four arguments: minimum exposure, maximum exposure, number of frames each, f/stop increment.

For example, min: 10ms, max: 1000ms, frames: 10, increment: 1
yields:
10 frames @ 10ms
10 frames @ 20ms
10 frames @ 40ms
10 frames @ 80ms
10 frames @ 160ms
10 frames @ 320ms
10 frames @ 640ms
10 frames @ 1000ms
Done.

Practice, practice, and practice some more. Use the Moon or a distant terrestrial object.

Brian

EDIT: Here is a good website to visualize the path of totality. Where are you planning on setting up?
https://www.greatamericaneclipse.com/april-8-2024

[Moonstruck]

Thanks Dave and Brian.

Brian- how do I write a script in Sharpcap? With the sequencer? How exactly do I do that? I haven't ever used the sequencer before.

I saw a CN post from someone who automates Sharpcap to take 5 exposures (0.4, 4, 40,400 and 4000 milliseconds) in 5.6 seconds, and loops that routine during totality. How would I do that?? No idea what commands to use or how to program it.

[Moonstruck]

Brian- to answer your question - I plan to set up in Stowe, VT. An expensive trip for me (from CT). Hotels are outrageously expensive in that area during the eclipse, but I figure it's worth it. This may be a once in a lifetime thing. I just hope it isn't cloudy!

[oopfan]

I'm also from the Northeast. The NE is not the greatest choice for clear skies. I was hoping you would say Texas. See if you can find a website that can give you the probability of cloud-free skies in Stowe on that date, then compare it to say Waco, Texas.

Brian

[oopfan]

Since you are new to scripting, I'd suggest not trying to script it until you become more familiar with it. Instead, use SC's "Start Capture" tool to capture 4 minutes of fixed-exposure frames. What exposure? It's the minimum exposure that pulls the light energy away from the left-hand-side of the histogram. We can talk more about that later. Dave (turfpit) is expert at using the histogram. His advice is sage. Once you start the capture, you can sit back with family and enjoy. However, check SC every so often to ensure that the Sun is still centered in the frame. Make manual corrections as needed.

Once you return home then you can start the process of stacking two or more frames to synthesize longer exposures which will bring out the outer corona. Lots of people here to guide you through that. By the way, what is your field-of-view? If you don't know we can give you a website to help figure that out. Ideally you want your field to fit three Suns in a frame.

Brian

[oopfan]

I ran a calculation on your field-of-view given the specs of your scope and camera that you provided in your post. Your FOV looks great but like I said keep an eye on it. Don't let it drift too far out of center:

Screenshot 2023-12-10 at 2.46.46 PM.png (183.9 KiB) Viewed 10281 times

My last concern is for you to make sure that you won't have trees blocking your view at totality. Here is what my calculator came up with:

Screenshot 2023-12-10 at 2.46.05 PM.png (127.4 KiB) Viewed 10281 times

So, the Sun will be 40 degrees above the horizon in the direction of west-southwest (WSW). I was concerned it would be lower than that.

Finally, you're not on the totality centerline, so I estimate you will have 3 minutes of totality, maximum.

Brian