DSS, Registax and Rot n' Stack, why won't they align & more problems

[EA2007]

Hey kids,

For some reason whenever I use Deep Sky Stacker (DSS) after going through all the processes, I am left with an image which is:

a) black and white

very noisy and blocky

c) NEVER aligned!

I have to say, as a widefield imager (using a tripod and dSLR, don't yet have a decnet EQ setup for scope imaging) that sometimes my frames are out of alignment i.e. the target will switch position lsightly in between shots........but surely the program can account for changes in position, especialy given that it has the ability of 'standard and mosaic' alignments.......for some reason my results always show trails as if the program has stacked without aligning, also the final image is pretty crud.

the same goes for Registax, if I use the 'single-point' alignment method it aligns around 1 star, thuis meaning those further away show field rotation and star trails, yet if I choose 'mulitple-point' aligning then it always comes up with a random error and only uses 1 frame to stack.....do you have to go through every frame and choose multiple targets or just choose multiple targets on the first frame and the program does the others automatically ? plus I can never seem to get the final frame using the slider bar

can anyone help!! its not difficult is it, I mean every imager on here can do it, why not me!!

[jgs001]

The lack of colour, is down to the DSS stretching, boost the saturation by 25% in the DSS sarutation tab. You need to adjust the curve position, and the luminousity values (on the second tab), to balance out the grain and detail. Or, save with the enhancement's embedded, instead of applied, and adjust it by hand.

[Psychobilly]

Its also possible to shoot too wide for DSS to be able to cope with... the lens distortion in toduced couple with the rotation between shots can often cause DSS to fail...i tend not to shoot wider then 28mm now when i want to stack in DSS...

AS John Pointed out you need to tweak saturation and lumionosity in DSS...

Billy...

[jgs001]

I've had DSS work fine with shots from the kit lens at 18mm, and that's got quite a lot of Barrel Distortion.

[Psychobilly]

Hmmmm....thats Interesteting John,

DO you do anythign speciific with the alignment of the cam...

I couldn't get it to Stack images from a 10-20 till i cropped the images down considerably... When I just aligned along the Milkway rateher level with the horizon...

When i tried to manually do it in CS then it was possible to get alignment around the center but the edges we way out ... in the end I "flattened" the images in CS before stacking ...

I'll revist the data with Registar (not Registrax) becasue according to the blurb it will correct the image gemoetry as well...now where did i put those old files....

Billy...

[jgs001]

Hmmm. Nope. I setup the camera on the tripod at 18mm, fired a sequence of 10 with some darks, and threw them all into DSS. I've done this with even more when I was using my Z2.

Here's an example from the 450d

[Psychobilly]

ah you have much tighter stars in that image around the edges than i got with the 10-20 which is probably whats confusing DSS in my case...

Heres the best i could get out of it....

(click to enlarge)

Cheers John...

[jgs001]

I guess it's something to do with the lens :shrug:...

Anyway we digress. I've not had a problem with alignment in DSS even when capturing 30s shots at 18mm over a period of an hour. What I've found is that as the duration gets up beyond probably 10 minutes, the more the upper right and lower left corners appear to smear after the stack. I can only think that this is the effects of the field rotation (over time, rather then between images) creeping in.

[Psychobilly]

Agreed we are digressing its probably a case of suck it an see with the paricular steup that your using and over a period of time you'll establish a sweet spot ... in terms of Focal length max exposure times etc...

If only we had enough clear nights so that we didn't feel pressured in getting useable data every time we went out...and feel so miserable when we go to process waht we captured only to find it isn't what we were hoping to achieve....

Billy...

[EA2007]

I'll give you all some visual examples when I have some spare time............pinching my mothers lappy at the mo.