Make Stars Smaller

[astronomynut]

I am back at trying to figure out how to use Star Tools. Though I am very bad at it right now, I have improved a little since I last posted.

My latest edition to my photography collection is the Horsehead Nebula, and surrounding area. During my photo session I took 25 400 second subs, but only managed 15 of them as passable to my standards. But even with the reduced data, the bright star Almitak and several others in that area took center stage by being so bloated.

I was wondering if there is any way, with Star Tools, to reduce the size of stars that are bloated. It would be nice to see them not so prominent, so that the eye takes in the Nebula, instead of the radiant, bloated stars. If someone could point me to the procedure on how to achieve this, if it is possible with this software, I surely would appreciate it. Caley

[Rowland]

Caley. "Decon" Select generate mask automatically. To get you started.

[admin]

Note that decon will have a hard time with 'fat' stars (e.g. stars with overexposed/white cores). If decon isn't appropriate or doesn't work properly for you (it's highly dependent on the data), you can use the Magic module (choose the Shrink or Tighten algorithm). A star mask (that tells the Magic module where exactly the stars are that you want to shrink) is required.

If you have a very busy star field with lots of small stars, the Life module's Isolate preset (without a mask) is another nice way of bringing nebulosity to the fore.

[astronomynut]

Thanks so much for the tips. I got a comment on my photo, not to shrink the one big star, as it looks great. This came from someone who is an experienced photographer. Kind of makes me feel I am starting to get the hang of this software, at least the basics of it. Caley

[admin]

Thanks so much for the tips. I got a comment on my photo, not to shrink the one big star, as it looks great. This came from someone who is an experienced photographer. Kind of makes me feel I am starting to get the hang of this software, at least the basics of it. Caley

Fantastic to hear Caley!
And yes, Alnitak is such a bright star/blob that it should just be embraced. With some judicious stretching (which in StarTools is simply using the AutoDev module), the halo can be kept under control and Alnitak B can sometimes be seen as separate from the halo, despite Alnitak A's brightness. That's of course if you have a high enough resolution, had good seeing and you care about these things in the first place.