6. Editing the astro photos  

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    When DSS has processed your pictures, it opens up the result, a often "milky white" diffuse picture. First time reaction, "What the ....". Well, it's adjustable, look below the picture. 
    Here we have three tabs, "RGB/X Levels", "Luminance" and "Saturation". These is the controls we need. Below the tabs is a small window with either three colored slides and spikes or six slide controls, depending on if we in the "RGB" or "Luminosity" tab. 
    If running under Windows, we will in the "RGB" window also have a S-formed luminosity curve. My experience running DSS under Wine (Linux), this will become a strait line. Anyway, time to adjust. If you have the S-curve, move the "RGB" color slides so all three spikes is completely overlapping each other and placed on top at the initial lower left flank of the rising S-curve. Also adjust "Saturation" to around 18 (move slide to see value). 
    Then press the "Apply" button under the "RGB" slides and see how the picture transforms to a viewable picture. Quality depends on number of pictures, exposure time and quality of our "flats". Since I regularly use my camera's max remote time, 30 sec, for my AltAz telescope mount, I usually get something :-). But now we can enhance the picture? Normally by moving the "RGB" controls some in each direction, but where the spikes should cover each other at most times. 
    Also go to the Luminosity tab, here the "Mid-tone" slides seem to be the one giving best effects. The lower of the two middle slides often needs a value between 32.7->34.5, while for the upper I use a value of 2-7. The top control, the "Darkness", I set at 0 for the top one and 98.2 for the one below. The bottom control, "Highlight", there the upper also is set to 0, while I have the lower between 45-69. 
    All this is both camera as telescope tube dependent, so you need to test for best options.   When have a satisfying (or best option) resulting picture, we save it with the "Save picture to file" option, a bit down on the left. However, we're not ready, we need to open the saved picture in a photo editor, the one of your choice. 
    Me? I use GIMP since years back. Tried PS10, but never liked it, to complex. Then, when going Linux for a time, PS10 also became a non-option.  What I do in GIMP is the following:  

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      - Load the picture (press OK to the Tiff and 8-bit warnings) 
      - Go to Colors -> Auto -> Stretch Contrast. 
        Look at the picture, if the picture improves, I continue with 
      - Color -> Auto -> Normalize .... 

 

    Usually the colors is still a bit dull, so I normally go a tour around Colors -> Hue/Saturation and plays with the slides to improve color and if not helping, to Colors -> Color Balance. All this is a lot of feeling and experimenting; me being partial color blind, I am therefore not the best person to advice on this. 
    As a last step, when satisfied, I found that a lot of my pictures win on me, doing one or two Filters -> Enhance -> Unsharp Mask (2) or, if installed, Wavelet sharpen (0.4). Usually brings forward a 3D effect in the pictures. But use it with care, the in the Gallery section included Orion Nebula did not like that trick a bit, it went very coarse and grainy. 
    You should now have your first astro photo, hopefully with a lot of stars, maybe a galaxy or nebula. After stacking your pictures in DSS and edited them in GIMP/PS or some other photo editor, your still a newbie, but also an astro photographer.