Removing glare from eclpse photos

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Removing glare from eclpse photos

Postby tim.tlz » Wed Aug 10, 2016 5:39 pm

Hi Everyone

I am hoping to go to the USA next year to see the solar eclipse and I would be very grateful for some advice with photographing it.

It seems that the great majority of eclipse photos on the Internet have a lot of glare in the area of the corona nearest to the Sun which pretty much obliterates any detail in the corona. However, the famous eclipse photos by Miloslav Druckmüller have almost no obstructive glare in them at all, allowing you to see all of the fine detail in the corona right next to the sun. Does anyone on this forum know of the best combination of filter and F-Stop in order to get rid of the glare and allow the detail of the corona near the sun to be seen?

Please note that I plan to use stacking software in order to produce my final results so I will probably be using very short exposures for each individual image.

Thank you very much.

Kind regards

Tim
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Re: Removing glare from eclpse photos

Postby Gfamily2 » Wed Aug 10, 2016 11:24 pm

tim.tlz wrote:Hi Everyone

I am hoping to go to the USA next year to see the solar eclipse and I would be very grateful for some advice with photographing it.

It seems that the great majority of eclipse photos on the Internet have a lot of glare in the area of the corona nearest to the Sun which pretty much obliterates any detail in the corona. However, the famous eclipse photos by Miloslav Druckmüller have almost no obstructive glare in them at all, allowing you to see all of the fine detail in the corona right next to the sun. Does anyone on this forum know of the best combination of filter and F-Stop in order to get rid of the glare and allow the detail of the corona near the sun to be seen?

Please note that I plan to use stacking software in order to produce my final results so I will probably be using very short exposures for each individual image.

Thank you very much.

Kind regards

Tim

The intensity of light of the corona is likely to fall off as the inverse square of the distance from the surface, so I would suggest that the only way to get that level of detail across the width of the corona would be to use a graduated circular filter that you centre on the Sun.
The alternative would be to create a HDR image, whether by using in-camera processing (I would recommend against this) or by taking sequences of bracketed images and using them to generate your own HDR images after the event in software

The images by Miloslav Druckmüller, do (to me at least) look as though they have been generated through a HDR process.
The reason I would not recommend using any in-camera HDR processing is that it simply takes too much time - it may mean you can only take a handful of images during the period of totality, whereas you could take several bursts of multiple images across a wide range of exposures so that you can combine 3 or 5 sets of images to build your HDR image.

ETA - looking at Druckmüller's webpage, it's clear that he uses multiple images and software to generate his photos - 25 images in this example, with exposures from 8 seconds down to 1/4000s
http://www.zam.fme.vutbr.cz/~druck/Ecli ... 0-info.htm
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Re: Removing glare from eclpse photos

Postby tim.tlz » Wed Aug 10, 2016 11:41 pm

Hi Gfamily

Thank you very much for your detailed reply.

Unfortunately, Miloslav Druckmüller's website does not seem to make clear what F-Stops he uses or whether he uses any filters. Do you have any idea about this?

Thank you very much.

Kind regards

Tim
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Re: Removing glare from eclpse photos

Postby Gfamily2 » Thu Aug 11, 2016 12:27 am

tim.tlz wrote:Hi Gfamily

Thank you very much for your detailed reply.

Unfortunately, Miloslav Druckmüller's website does not seem to make clear what F-Stops he uses or whether he uses any filters. Do you have any idea about this?

Thank you very much.

Kind regards

Tim

From the image details provided, he's using a 105mm f5.9 APO scope, but it's hard to tell what the effective f/ratio is, as he's got the FFC in the image train before reaching the DSLR sensor.

His website for Solar Eclipse imaging has the following instruction set from 2009, presumably he had a team working with him. There's no indication he expects any filters to be used.
http://www.zam.fme.vutbr.cz/~druck/Ecli ... ctions.pdf

I think I would be surprised if the software he uses is available to the general public, but I guess there's no reason why you shouldn't send him an email and see if you get a response back.

Good luck, and clear skies.
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Re: Removing glare from eclpse photos

Postby Gfamily2 » Thu Aug 11, 2016 12:36 am

Gfamily2 wrote:From the image details provided, he's using a 105mm f5.9 APO scope, but it's hard to tell what the effective f/ratio is, as he's got the FFC in the image train before reaching the DSLR sensor.

Just in case you're a photographer rather than an astronomer :), this means that it's the aperture that's 105mm, if this was a 'camera' lens it would be sold as a 620mm f/5.9 lens (for a 35mm full frame camera)
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
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Re: Removing glare from eclpse photos

Postby tim.tlz » Thu Aug 11, 2016 12:41 am

Hi Gfamily2

Thank you very much indeed for your further detailed replies.

Kind regards

Tim
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Re: Removing glare from eclpse photos

Postby The Man with the Corrugated Iron Roof » Tue Sep 27, 2016 7:52 pm

You can download GIMP, to process the photos, from here:

http://www.philippughastronomer.com/Downloads.html

The Curves function removes glare.
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