NGC7789 - Caroline's Rose: First guided collection, Michele Vonci

NGC7789 - Caroline's Rose: First guided collection

NGC7789 - Caroline's Rose: First guided collection, Michele Vonci

NGC7789 - Caroline's Rose: First guided collection

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Description

First guided experiment! I managed to take 17x5 minutes subs imaging the beautiful open cluster NGC7789, also known as Caroline's Rose.

I'm quite sure 5 minutes exposure are too much for my camera and as a consequence I saturated all the stars. Luckily, stars are just bright points of light and are relatively easy to fix....I actually found a long discussion on Cloudy Nights about how to reconstruct a Gaussian profile in a saturated star. After a good deal of fiddling and tweaking with Photoshop filters I managed to get something decent...but I'm not totally happy yet...I'll might come up with a new version!

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Revisions

  • NGC7789 - Caroline's Rose: First guided collection, Michele Vonci
    Original
  • NGC7789 - Caroline's Rose: First guided collection, Michele Vonci
    B
  • NGC7789 - Caroline's Rose: First guided collection, Michele Vonci
    C
  • NGC7789 - Caroline's Rose: First guided collection, Michele Vonci
    F
  • Final
    NGC7789 - Caroline's Rose: First guided collection, Michele Vonci
    G

B

Description: Alternative version. I did not reduced the size to 50% in this case

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C

Description: I keep experimenting the various solutions for overexposed stars I found on this thread on CN: https://www.cloudynights.com/topic/497669-a-fix-for-overexposed-stars.


This time I have used the method proposed by the user spokeshave:
"There is a relatively simple technique I use in Photoshop that works fairly well. First, you need to select the starts. To do this, make a copy of the background layer, and then apply the dust and scratches filter to the copy by pulling the radius up until the stars just disappear. Then blend the copy with the background layer using difference. This should make only the stars visible. Don't worry if some small remnants of your target are visible. You can then select the stars using the "color range" option in the select menu. Once you have the stars selected, you can delete the background copy layer. You'll also need to expand the selection by using the "modify-->expand" option in the select menu. I usually expand by between 5 and 10 pixels, but that will depend on pixel size and image scale. You just want to make sure that the "marching ants" have just a tiny bit of space around the stars. Next, you want to feather the selection using the "modify-->feather" option in the select menu. I usually feather by about half the number of pixels that I expand the selection. Finally, select "other-->minimize" from the filter menu. Click the preview box over a prominent star and select the radius that shrinks the stars by the amount that pleases you. Make sure that you select "preserve roundness" from the minimize screen. This process does a nice job of restoring a relatively Gaussian profile to the stars and you can just about make them as small as you want."

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Histogram

NGC7789 - Caroline's Rose: First guided collection, Michele Vonci

In these collections

Open Clusters