Elongated stars

[Dimitris Platis]

I am revisiting this old topic cause I havent found a satisfactory answer....
I am using a Nikon 180ED and I get elongated stars especially at the edges...so I cant just fix the issue, cause there isnt any issue and the only things I cant do is fix the problem after the fact.
I would appreciate any suggestions if possible accompanied by a tutorial or any source where I can get info on the subject.

I appreciate the help

Dimitris

[Geoff]

There are many causes of elongated stars, so without a picture from you it is impossible to give advice on tackling the problem
Geoff

[Dimitris Platis]

I will post a photo soon...but the elongated stars are due to lens aberration. I am not seeking technical advice on guide, flexure etc..but rather a Pixinsight methodology (Decon, Morphological transformation) for correcting the issue.
 

[Geoff]

Hi Dimitris
I think you'll find that PI is not big on correcting hardware problems with software.  There is an interesting thread here http://pixinsight.com/forum/index.php?topic=4443.0 which may seem off topic at first, but it gets around to talking about elongated stars. Juan's comments on correcting these are particularly interesting. He is talking about tracking error, but I think his comments apply equally to your case. I have had a similar problem of elongated stars in the corners due to field curvature. There are various choices: live with it, get a field flattener, buy a better scope, use a smaller chip etc etc. Don't try to correct it with software.
Geoff

[Ignacio]

Have you tried Photoshop filter "Lens Correction"?

Ignacio

[JGMoreau]

Hi Dimitris,

Best for correcting your stars is StarTools.
And making them nice looking too. 8)

https://dl.dropboxusercontent.com/u/97102214/Abell43.jpg

Cheers,

JG Moreau
Quebec

[Dimitris Platis]

I found that the Morphological Transformation tool works great if u adjust the shape of the dotted square...!!

[Juan Conejero]

Have you tried Photoshop filter "Lens Correction"?

Best for correcting your stars is StarTools.
And making them nice looking too.

Hi guys. I'm not going to moderate your posts this time, but please realize that this is PixInsight Forum. On one hand, promoting competing products is in general not permitted. Besides that, this forum is for real image processing. There are hundreds of forums, groups and communities on the Internet were I'm sure you'll find tons of information on this kind of tricks, toys and magic recipes. This forum is definitely not the right place for these.

[JGMoreau]

My apologies for breaking the rules.
I am reading the forum for long enough to know better.
Won't happen again 

Jean Guy

[Geoff]

"tricks, toys and magic recipes" is a good summary of some of the stuff out there.
Geoff

[Theaetetus]

Hi Juan. Getting back to “real image processing”, I would be interested in your opinion on the possibility of handling aberrations such as field curvature using spatially-variant PSFs and deconvolution. There are some papers on doing this in the professional literature that I have come across. Do you think that this approach could be useful for amateur astrophotography? Thanks!

Have you tried Photoshop filter "Lens Correction"?

Best for correcting your stars is StarTools.
And making them nice looking too.

Hi guys. I'm not going to moderate your posts this time, but please realize that this is PixInsight Forum. On one hand, promoting competing products is in general not permitted. Besides that, this forum is for real image processing. There are hundreds of forums, groups and communities on the Internet were I'm sure you'll find tons of information on this kind of tricks, toys and magic recipes. This forum is definitely not the right place for these.