From: Bluuuue Rajah Bluuuuue@Rajah.
The average person would use Photoshop for that,

Does the *average* person even *have* Photoshop in the first place?
It's my understanding that it doesn't come with any of the popular
operating systems, and is rather expensive to purchase, and illegal
to download without purchase. Is that correct? If so, I would guess
that a very small fraction of people with computers have Photoshop.
I don't know anyone around here who has Photoshop, and I'm pretty
sure none of the public computer labs around here have it. There's
just one person I knew in late 2000 who did a lot of editing of
photos and probably had it, but she lives 1.5 hours from here and
hasn't answered any of my e-mail for several years so I don't think
I can ask her to let me use her copy even if she has it.

but did you stop to think that there will then be a big black
disk on the picture of the galaxy?

I seriously doubt that would be the result. When I look at an image
of the Andromeda galaxy, I see some continous texture such as
spiral arms and hydrogen-alpha regions and the central bulge, and I
see several point sources, which I don't know whether they are
super-bright objects in the Andromeda galaxy or medium-bright
foreground stars in our own galaxy. If every last one of those
bright point sources are in fact blurred out, there wouldn't be
what you claim.

There is a programming language associated with Photoshop,

I've never even *seen* Photoshop, much less used it, so that's news
to me, good news if true. So it may be possible to use an external
program to automatically scour Sloan and/or Hipparcos databases to
produce a list of locations of foreground stars in the field of
view, and write out their approximate pixel coordinates. Then have
a Photoshop program import that data and match the given
coordinates with point-like bright spots in the actual image and do
least-squares fit between predicted pixel coordinates and actual
image bright-spot coordinates, and thereby produce *true*
foreground-bright-spot pixel coordinates. Then for each spot
calculate a peak brightness and radius of diffraction/blur based on
picture data, then do a least-squares fit of that info across all
the image to learn the effective diffraction size and blur function
as they vary across the image and to learn the response function
that relates true apparent magnitude with the brightness in this
image, in each of the color channels separately. Then use that
result to do the actual blurring wherever the predicted total
brightness-addition due to blurred diffracted star image is greater
than some threshold.

but if you want to do it yourself, you'd have to write a program
to edit the image file.

I've been looking for software libraries in any of the various
common programming languages that are able to process JPEG files,
for a different purpose but applicable for this task too, and
posted a query to comp.lang.lisp a few days ago, but nobody
responded yet with info I can use easily, according to Google
Groups which might not be working properly so I can't really be
sure nobody responded. Checked just now, found the thread again:
http://groups.google.com/group/comp....ex/browse_frm/
thread/85ee2ccfc158a0f5/d36d76676bfc469e?hl=en&_done=%2Fgroup%2
Fcomp.lang.lisp%2Fbrowse_frm%2Fthread%2F85ee2ccfc1 58a0f5%2Fd36d
76676bfc469e%3Fhl%3Den%26tvc%3D1%26q%3Dinsubject%2 53Ajpeg%2Baut
hor%253Auh3t%26&hl=en&tvc=1&q=insubject%3Ajpeg+aut hor%3Auh3t
= http://tinyurl.com/6oaur6
It has one reply I hadn't seen yet, but it isn't of much further
help, so I'm still lacking anything I can readily use.

It should be simple enough to just set the various pixels within
a specific range to black,

Ug! I'd rather blur than blacken. Ideally I'd have the ability to
create a flashing image, which flashes back and forth between
original and blurred, or back and forth between smooth-blurred and
checkerboard-dither-blurred, so that I can easily see which places
to ignore where I'm not seeing the true data in those regions.

Still, blackening the vicinity of foreground stars might be a quick
first step just to see if that's good enough so that I don't need
to do what I currently think I want to do.

but different photos would have different exposures and
contrasts, and I have no idea how you'd handle that.

Also different diffraction limit, quad or bi or hex diffraction
spikes depending on telescope design, different blurring due to
seeing conditions combined with exposure time, different function
change over whole image due to different coma correction or
astigmatism or spherical abheration or local displacement due to
variation of refraction from average seeing conditions due to
too-short exposure etc.

http://shell.rawbw.com/~rem/WAP/projectIdeas.html
I have no idea how to find anyone interested in working with me on
any of those projects, and I have no idea how to write up any of
them as a formal proposal that anyone would pay serious attention
to.
I have a friend with a company that does precisely this, but he
charges real money.

I have no real money whatsoever. It'll take me until I'm 80 years
old before I have credit cards paid off, if I live that long,
before I might possibly have income not already owed to credit
cards that I would be free to spend on anything for myself.

See if your phone book has listings for either "business plans"
or "business consultants."

If they pay money to get listed in the Yellow Pages, then
presumably the expect to charge me money I don't have to reimburse
them for their investment in Yellow Pages advertising.