Unistellar - Simple Image Processing (in Adobe PSE)

Introduction | Image Processing in a few Steps... | Conclusions | Links

On this page, I briefly introduce how I edit astromy photos taken with the eVscope or an astronomy camera in a simple and quick way using Adobe Photoshop Elements. This page is suited to all eVscope versions (the images were taken with an original eVscope).

Note: See page Overview of the Unistellar pages for just that!

 

Introduction

On this page I present an example of how I process astronomy photos, which I took with the eVscope or an astronomy camera, with a few editing steps in Adobe Photoshop Elements. It is a process that I have "gotten into the habit" of over time, and I have always fallen back on it after trying other procedures or programs, because it yields quick results. Certainly, much better results can be achieved with more sophisticated editing methods. All in all, this is a simple "quick start" method.

         

M 13 - Jul 18, 2021

 

M 13 - Jul 18, 2021, processed

 

M 13 - Jul 18, 2021, processed and sharpened

   

M 27 - Nov 2, 2020

 

M 16 - Aug 23, 2020

 

M 51 - Mar 6, 2021

   

M 27 - Nov 2, 2020, photo on top processed

 

M 16 - Aug 23, 2020, photo on top processed

 

M 51 - Mar 6, 2021, photo on top processed

Photos: Examples of unprocessed and processed DSO (taken with Unistellar eVscope)

 

Image Processing in a few Steps...

First, I load the image (M 81, Bode Galaxy) into Adobe Photoshop Elements (PSE in the following):

In the first step, which can also be skipped, I try to reduce the contrast in the image and to reveal more details. For this, I select "Enhance > Adjust Lighting > Shadows/Highlights...":

A dialog opens, where I typically only use the "Lighten Shadows" slider. The preview is activated and demonstrates the effect of the preset value of 35%:

Since I regard this as too bright, I reduce the effect in thos example to 20% (I set the slider "according to my taste"; the preview to "on" so that you can see the effect of the "Lighten Shadows" slider):

Here, I set the preview to "off" so that you can make a before-after comparison.

In the next step (as written above, you can also leave out the first step...), I select the "Levels" tool, which displays a histogram of the color or b&w values:

Here, I also start with the preview "on". The sliders are for setting the "black point" (left), the "gamma value" (center), and the "white point" (right):

Usually, I use only the left and center sliders (the "white point" slider is said to be "forbidden" for astronomy photos...):

So, some fiddling with both sliders may be required for achieving optimum results. Anyway, adjust the image to your taste!

Now, this would be the (preliminary) end result (which is a matter of taste, of course...):

Depending on the subject, I sometimes add a sharpening step (Enhance > Unsharp Mask...). I do this typically for globular star clusters and some open star clusters.

And here is the photo of M 81 before and after processing:

    

M 81 - unprocessed

 

M 81 - processed

 

M 81 - processed without step 1 (without Highlights/Shadows)

 

M 81 - processed alternatively

For illustration purposes, I present two more edits: on the right, there is a stronger edit in the "Levels" correction, and on the left, there is one without the "Shadows/Highlights" step, but with higher values in the "Levels" correction.

 

Conclusions

This simple image processing serves only to improve the general appearance of astronomy photos in terms of brightness and contrast (and sharpness if necessary). There is no processing of colors, that is too much a matter of "taste" for me...

 

Links

 

An den Anfang   Homepage  

gerd (at) waloszek (dot) de

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20.09.2022