Dealing with a really hazy Sun in Photoshop

[Bizibilder]

Today's Solar image was taken through a really hazy sky that seemed to eliminate just about all detail when viewed on my laptop screen.  I used my regular setup of ED120mm APO and Canon 1100D, ISO 100 and 1/1250 sec exposure.  The frames were stacked in Registax5 and a stack of 76/200 frames made.  My normal processing workflow is described here:  http://stargazerslounge.com/topic/153712-simple-white-light-solar-imaging/?hl=%2Bsolar+%2Bimaging+%2Bbizibilder#entry1569413

There was no way this was going to produce an acceptable image so, after quite a bit of playing around I found that I could extract a reasonable image using Photoshop on the stacked image.  This is the method used:

Open the stack and you will see this:

Open the Levels window and you will see two huge peaks, the right hand one is the image of the Sun and the left hand one is the haze surrounding the Sun:

Do an "Auto Colour" to balance the RGB channels (This is what I do as part of my normal processing):

You can claerly see the huge halo of haze around the Solar disc - this is what we are trying to eliminate.

Move the black point slider to the edge of the left hand peak:

Close levels and reopen it, then move the black point slider to completely remove the left hand peak:

This has removed the halo and left you with a much cleaner image:

- at this point I resumed my regular processing workflow.  I hope this helps for those all to often occurring "hazy skies"!!

[David Smith]

Good info Roger, thanks. Do you know if the PS Autocolour function is equivalent to the RGB Balance in R5.1?

The rest I can do in GIMP2.6 but not sure about this part.

[Bizibilder]

I suspected they may be similar but I have just done an RGB align in R5 and the result is quite different to an Autocolour in PS.

[JB80]

Top tip Roger, thank you for sharing that info and doing that write up.

I will definately remember that one.

[Steve Ward]

I just use the Histogram and Contrast adjustments in Wavelets to achieve the same thing.

I sort the overall 'look' of the disc before any sharpening is applied so I have a consistent starting point.

Any minor tweaks I do in Gimp after cropping ( which I do in LivePhotoGallery as It has a convenient 'Square' setting ) these are usually a just combination of GBlur and USMask.