TECH QUESTION FOR SOLAR PHOTOGRAPHY EXPERTS

I am not a solar expert but my guess from what little I know, is that the longer exposure to needed for the prominences also picks up the fainter part of limp, slightly extending it outward. I see this in a lot of solar Ha images and I suspect it has something to do with how narrow the filter band is. No idea what the processing fix is. I’m hoping the solar guys here will jump in on this thread.

Thank you

The astrobin user GreatAttractor is the guy who makes the program. I’m not going to bug him with that. I’ve already asked him for feature requests (that he says he may implement.)

I have SolarToolbox too, I use it only for orange coloring with one click. When I do processing with it, the Sun always seems “overbaked.” I guess I should work with the settings more than the little I have.

But I know this is an issue with imPPG settings, I just don’t know what to change. I think imPPG is the way to approach it, since it’s the classic main program used for this.

Good reply though.

dan baldwin · Jun 7, 2026, 03:01 PM

Not an expert by any means but I have been doing daily solar Ha for about a month and this is what I do:

1) set up an lucky imaging sequence with normal exposure so that none of the plage regions are blown out.

2)After stacking this in AutoStakkert4

3) I sharpen and brighten (if needed) resulting stack in IMPPG.

4) Bring the sharpened image into Photoshop and duplicate it,

5) copy one of the images into the other so that there are two layers.

6) Name one layer Surf and the other Prom. I put Surf on top and Prom on the bottom.

7) draw a tight circular selection around the solar disk of Surf with a feather appropriate to your image scale ( for my Player One Saturn SQR with 1.25x Barlow its 5 pixels), then make the selection a mask.

8) Now a curves adjustment layer can be used to brighten the prominences without affecting Surf.

If you dont have PS, other photo processors (GIMP) have same layer and masking capabilities

I used to take two separate exposures, one normal and one exposed for proms, but realized that a normal exposure still contains enough prom data that that they can be resurrected by using curves. Its been my experience that the limb looks more natural using one exposure than dealing with minor differences that are inherent in two separates.

Fascinating and I’m going to try it. Thanks!

Did you do that on all 3 still images of the Sun of yours on here? The rest are animations, I’m guessing you didn’t do it on there?

If not all 3, can you tell me which of your images on here you did with this technique?

Someone else suggested also shooting at a lower gain. I’m at 75 percent histogram, maybe I should try 70 or even 65.

dan baldwin · Jun 7, 2026, 03:36 PM

The astrobin user GreatAttractor

Yes.

The AstroBin user GreatAttractor is the developer of imPPG.

Check out his DIY 10” solar Newt:

https://solarchatforum.com/viewtopic.php?t=49359

(Has an un-coated primary mirror, like most / all Newts that are made to not catch their cameras on fire. lol)

Michael W. Dean · Jun 7, 2026 at 03:10 PM

dan baldwin · Jun 7, 2026, 03:01 PM

Not an expert by any means but I have been doing daily solar Ha for about a month and this is what I do:

1) set up an lucky imaging sequence with normal exposure so that none of the plage regions are blown out.

2)After stacking this in AutoStakkert4

3) I sharpen and brighten (if needed) resulting stack in IMPPG.

4) Bring the sharpened image into Photoshop and duplicate it,

5) copy one of the images into the other so that there are two layers.

6) Name one layer Surf and the other Prom. I put Surf on top and Prom on the bottom.

7) draw a tight circular selection around the solar disk of Surf with a feather appropriate to your image scale ( for my Player One Saturn SQR with 1.25x Barlow its 5 pixels), then make the selection a mask.

8) Now a curves adjustment layer can be used to brighten the prominences without affecting Surf.

If you dont have PS, other photo processors (GIMP) have same layer and masking capabilities

I used to take two separate exposures, one normal and one exposed for proms, but realized that a normal exposure still contains enough prom data that that they can be resurrected by using curves. Its been my experience that the limb looks more natural using one exposure than dealing with minor differences that are inherent in two separates.

Fascinating and I’m going to try it. Thanks!

Did you do that on all 3 still images of the Sun of yours on here? The rest are animations, I’m guessing you didn’t do it on there?

If not all 3, can you tell me which of your images on here you did with this technique?

Someone else suggested also shooting at a lower gain. I’m at 75 percent histogram, maybe I should try 70 or even 65.

I definitely used it on 6/3 and 6/6 I can’t recall if I used that on 6/1 but I think so. @BYoesle on cloudy nights suggested to me that two exposures are not necessary.

For the animations I have been doing a similar process on the completed animations, but using the free version of Davici Resolve. It took me a while to figure out how to do it, but it seems to work OK.

I love doing the animations but they take a lot of effort.. setting up the guiding and tweaking the focus every 15m as the temps shoot up. I’m very much a beginner and if you (or anyone) has any suggestions for improvements I would really appreciate it.

As for the gain, I’m uncertain, I’ve been setting it to below 100 or even at 0 for the FD stacks, but raising it over 100 for the animations to keep the exposures below 10ms. For FD images I’m experimenting with using a composite of two frames using the ASI585MM with no Barlow as opposed to one frame with the SQR + 1.25x Barlow. The FDs that I’ve posted here have all been one frame with the SQR + 1.25x