Black strips? cause?

[Torazz]

Hi,

Could someone please tell me what is causing these black strips are at the edge of my final integrated image?

The image is comprised of a stack of 90 images and the first and last images are exactly the same so the strips are not edge artifacts caused by stacking.

Skywatcher ED100-PRO with field flattener on EQ6-R PRO mount. Imaged with Nikon D7200

Thanks in advance for any advice.

 

[Droogie 2001]

Are you using flats? Looks some sort of vignetting.

[happy-kat]

Did you take any flats?

Looks like vignetting.

[Droogie 2001]

LOL Happy-Kat. What was that a minute between posts? 

[Torazz]

Surely vignetting affects the corners, not straight black edges along the length?

[Droogie 2001]

Just now, Torazz said:

Surely vignetting affects the corners, not straight black edges along the length?

Depends on you imaging / chip size. Did you take flats?

[Torazz]

no no flats taken, should i use flats or just crop the edge away? because to be honest my D7200 doesnt really need darks i've found, so maybe flats and bias?

[happy-kat]

I'm seeing vignetting further in than just the edges.

[Torazz]

tbh i'm a bit confused because the ED100PRO with field flattener is reviewed as having no vignetting unless using a full sized sensor which i'm not.

[happy-kat]

Flats also help with dust bunnies which you may get at any time. I can't comment on whether your equipment should or shouldn't show vignetting.

Edit: now looking at it full screen I can see three dust bunnies.

[LightBucket]

It maybe the spacing between camera and flattener, if it is too much it may cause vignetting, and it is definitely vignetting..   

[Torazz]

thks happy-kat

[davew]

That looks like mirror box shading to me. Some seem to be affected by it and others not.

Flats may reduce the effect.

Cropping the worst of the dark shading could be the best bet and if there were edge stacking artefacts you'd do it anyway.

Dave

[vlaiv]

Yes, try flats, it is not vignetting as such, but rather sensitivity of pixels to angle of incident light, coupled with maybe less sensitive pixels on edges due to manufacturing process.

[happy-kat]

On my monitor I am seeing a obvious darker area that extends into the image much further than the edge dark strips and is much stronger on the right hand side.

[vlaiv]

10 minutes ago, happy-kat said:

On my monitor I am seeing a obvious darker area that extends into the image much further than the edge dark strips and is much stronger on the right hand side.

I agree, there is certainly vignetting but black strips are also there, and flats would probably fix both.

[LightBucket]

Gradient Xterminator plugin for PS will sort that out, or Astroflat Pro, also a PS plugin...then no need to flats.. 

[happy-kat]

I didn't think gradient exterminator sorted out the dust bunnies?

[LightBucket]

Just now, happy-kat said:

I didn't think gradient exterminator sorted out the dust bunnies?

Lol, no it doesn’t was just talking about the gradient...it is just to get the OP going before worrying about flats,....assuming he is new to all this

[Jessun]

I see this effect with my OIII filter in particular. I have to deal with it separately in processing. I almost think it's a CCD cover glass artefact, just because no other part of the imaging train is rectangular.

It looks like you may want to experiment with different flats too for vignetting.

/Jesper