Shooting through bad glass

[jjjnettie]

Sigma 70-300mm f4.5 lens @ 200mm
2 hours and 40 min of 10min subs.

What's that saying???
"Life's too short to be shooting through bad glass".

At least I have a heap of 10min darks to add to my library. :P

Just look at the left side of the image. ewww

[leon]

Na JJJ the saying is "Life is to short to look through bad glass" ;) and that saying is mine JJJ, :lol: :lol: yep see the signature. :D, but it is OK you can use it.

However not that bad of a shot, a bit overly bright but pretty good.

Leon :thumbsup:

[jjjnettie]

LOL there is only about 1/5th of the image that is actually sharp and without coma.
And I did use some poetic license with your quote. :D

[mswhin63]

Ouch, Had the same problem last night.

[gbeal]

Not too flash, I have to admit. More so on one side though, why?
Similar result for me as well, tinkering with a shot or two between the showers and the TV reducer didn't like being 60mm from the chip, I got warp factor 4 in each corner. Back to the drawing board. Nice doodad though.
Gary

[h0ughy]

jjj i think it is the stacking function - try a different setting

[jjjnettie]

Here's a single image. Not even the Distort-Lens Correction function can help with this one. :)

[h0ughy]

wow thats huge in distortion. its like the focal plane is not falling on the chip. i did stacking once before and had a result like yours but now i see it is the lens

[jjjnettie]

I have 5hrs of Rho Oph. that did that too.
Tried to combine 2 nights work. Separately they're fine, but they just won't stack up together.
Did you ever fix the problem?

[DavidU]

May be a lens element is tilted.

[h0ughy]

yeah i use pixinsight for combining different sessions

[irwjager]

Hi JJJ,

Maybe there's a better lens distortion correction plug-in for PS available? It sounds like the one that comes with PS is only for subtle distortions...
I was able to do quick correction that looks semi-ok with ST (probably good enough for stacking), so there may be hope for this data set yet!

Ivo

[multiweb]

Yeah that's what I thought too. Something nasty going on in there. The right side of the field shows some uneven reflection/illumination as well. Shame coz it's a nice shot.

[renormalised]

Either as Dave said, something's out of kilter, or that lens is a shocker.

[jjjnettie]

LOL That lens is a shocker. yep yep yep
But I had to give it a chance before relegating it to the bottom of the camera bag.

[erick]

It's got nothing on the $5 CCTV lens I bought off Ebay for my Gstar. :scared: But that wasn't bad glass, it was bad plastic :D (Got a much better Japanese KOWA lens now. Looking forward to when I get the first chance to point that at the sky.)