whats happened to me stars?

[blink138 (Pat)]

hello members i know i will have to get some other softwear for capture and stuff.......... however this is what dss done to my picture!
8, 15 minute exposures qhy10
tracking seemed very good and going from pic to quick in quick succession revealed no apparent movement between them
pat

[ZeroID (Brent)]

I think you have vignetting and optical train issues. Weird one for sure.
The rotational area down the bottom is really ..... weird

Can you specify your imaging train so we can get a better idea of the setup.
Has this setup worked OK before ?
Have you changed anything

[rustigsmed (Russell)]

I think that is a software stacking issue pat.

maybe try some different settings.

Rusty

[blink138 (Pat)]

thanks brent, basically still testing my newish qhy10 ccd so that is the new piece of equipment
apm 107 - 2 inch focusser - extension tube - lps p2 lps - ts 0.79 fr/ff (works great on 60da) - qhy10 ccd
pat

[blink138 (Pat)]

russell, yes maybe it does not like dss, i tried with a lower threshold in the settings but it made no difference
i will just have to bite the bullet and get nebulosity, i think i am going to need it anyhow
pat

[andyc (Andy)]

My guess (and it's not much more than that) is that it looks like DSS is misaligning the stars in the registration process. It may be mistaking hot pixels for stars, or more likely not consistently registering a good number of stars? Likely it found enough good stars in the central portion of the frame, but tried aligning on very few stars at the top and especially bottom (so the spline fit was more-or-less unconstrained by anchor points, or even constrained to the wrong points due to low density of anchors). The smoothing of the spline would feed back to introduce slightly poorer alignment near the middle of the frame. It sounds like you've already tried fiddling with the relevant parameters to get a good number of detected stars (if not, definitely fiddle with this!), so I'm not sure what else to suggest. Were the subs very noisy?

[rustigsmed (Russell)]

might be worth deleting the existing registration files as there is something amiss, raising the star threshold / trying with different setting. and going for something like intersection mode?

[LewisM]

I know this is like a broken record, but buy CCDStack - light years ahead of DSS. Yes, I know it's pricey (not that bad really), but it makes initial processing a cinch, and 99.9% of the time, faultless.

I had no end of issues with DSS, from running out of memory (on a 16gb RAM system, that was rich!), to it not finding stars (yep... couldn't find enough stars in an Eta Carinae shot or M8 shot...), to simply rancid results (besides taking forever to process a decent sized stack).

Once you go 'stack, you never go back

[kosh]

Hi Pat,
This looks strange as the registration looks pretty good for half the image, but
Then goes haywire around outside centre.
Just a guess, but I would think the spacing would be different for the FR/FF for the QHY10 and your 60D. Have you got the spacing right?

Of course I could well be wrong to me this appears an optical issue.

EDIT: What do the single subs look like? if you've given them a little stretch and they look pretty flat then it is probably DSS after all.

Goran.

[cometcatcher (Kevin)]

I've had this happen with DSS also. Can't remember how I fixed it. Played with a slider somewhere.

[Mosc_007 (Charles)]

I have also had DSS bugger up the stacking on rare occasions. When I do get one that doesnt work I just use Nebulosity to stack that one.


Charles

[blink138 (Pat)]

thanks for the replies people, i think and am hoping it is just a stacking issue and as many have mentioned try a different softwear
i am confident by just looking at the individual subs that there is no such movement present
pat