Post processing in Astrophotography - comparing images

 I am a novice when it comes to driving advanced post-processing tools like Siril, which, if you are getting into astrophotography, I highly recommend.

It does have a steep learning curve, especially the post-stack processing side. Powerful, but not intuitive.

But if you want quick results from your funky new smart telescope, you do have alternatives.

So let's have a look at some solar photography and see what happens.

Here is a untouched image, and the same image with some in-camera curve adjustment. The only edit is to crop the image.

The Sun, unmodified

With in-camera curve  adjustment

Straight away, you can see more detail - the penumbras are clearer in sun spots, the granulation is more obvious. 

Now let's look at what happens when you get heavy handed with Snapseed's structure and sharpening tools, adjusting the shadows and highlights a bit more, adding a touch of HDR and tweaking the colour balance.

Heavily post processed in Snapseed

First up, the granulation is very clear now. Those speckles are not JPEG artifacts - they are structures on the solar surface. You can clearly see the umbra/penumbra components of the larger sunspots, and the paler inverse sunspot regions. 

Lastly, let's apply Google Photo's tools to the image instead. 

Heavy post in Google Photos

First off, some key features. We have lost the umbra/penumbra differentiation, and centre highlight is accentuated. As Google Photos only operates on a full image, there are many things we cannot do there. But, there are some. First off, the pop and structure tools are arguably better than Snapseed's equivalents. The colour tools are different, but we have a better HDR tool available. The end result is interesting in that it particularly highlights the pale spot regions.

All of these are, ultimately the one image:
The original uncropped.

This is from a DwarfII, 1/200s, Gain 0, no binning, and 10  frames stacked in-camera. ND1E6 filter for sun protection.


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