this week-end widefields

[multiweb (Marc)]

Some shots I took this week-end with my Pentax *istD. Seem to have so problems bringing up the colours. Shot in raws (PEF) at ISO800/1600/3200 1min exposure through ED80 at prime focus - G11 - PHD guiding . Processed in CCD Stack. Bayer converted in one shot colour. Anyone have any idea what I might be doing wrong?
When I shoot inf TIFF colours are ok.

[gregbradley]

Hi Marc,

Specific cameras need to be programmed into software to handle the RAWs. I doubt CCDstack is programmed for any DSLR but it might be for a couple of Canon models. CCDstack isn't ideal for DSLRs, Images Plus is the one.
CCDstack seems to have poor memory management and colour images become unwieldy to handle, they become huge files and the computer starts going really slow. Images Plus does not do that.

So check Images Plus to see if it supports Pentax Ist D or shoot in Tiff if it doesn't. I am pretty sure Images Plus supports Pentax 1st D.

Take 30 x 1minutes and have noise reduction on or take some darks at the same temperature and subtract them in Images Plus.

A couple of other points - 1 minute is too short an exposure as you have a lot of noise and horizontal banding in the images. Try 5 minutes or even 10 minutes.

Also you seem to have some vignetting going on. Is there something obstructing the view of the scope/camera?

You need to also learn to do flats as you have dust donuts showing as well. Flats will get rid of these and most of the vignetting.
Simply put a white T-shirt over the end of your scope and take a few images with short exposures at dusk or dawn.

Greg.

[glenc (Glen)]

cluster-03 is M4 and cluster-01 is NGC 3293.

[TrevorW]

I've a Pentax K100d and I've had although limited good results with Deepsky Stacker brings out the colours (no need to do in RAW mode)

[TrevorW]

Also I'd take longer exposures and drop your ISO
IMO

[multiweb (Marc)]

Originally Posted by gregbradley

Hi Marc,

Specific cameras need to be programmed into software to handle the RAWs. I doubt CCDstack is programmed for any DSLR but it might be for a couple of Canon models. CCDstack isn't ideal for DSLRs, Images Plus is the one.
CCDstack seems to have poor memory management and colour images become unwieldy to handle, they become huge files and the computer starts going really slow. Images Plus does not do that.

So check Images Plus to see if it supports Pentax Ist D or shoot in Tiff if it doesn't. I am pretty sure Images Plus supports Pentax 1st D.

Take 30 x 1minutes and have noise reduction on or take some darks at the same temperature and subtract them in Images Plus.

A couple of other points - 1 minute is too short an exposure as you have a lot of noise and horizontal banding in the images. Try 5 minutes or even 10 minutes.

Also you seem to have some vignetting going on. Is there something obstructing the view of the scope/camera?

You need to also learn to do flats as you have dust donuts showing as well. Flats will get rid of these and most of the vignetting.
Simply put a white T-shirt over the end of your scope and take a few images with short exposures at dusk or dawn.

Greg.

Hi Greg thanks for the feedback. You're right. I use a beta version of CCD stack which has a profile for my Pentax *istD. The first thing I do with the raws is debayer using the canon matrix:
RG
GB

Then normalise, register & stack. This way I seem to get some colour but it's less than ideal. I also tried to stack first then debayer. That didn't work too well for me [The shots attached were processed this way].

CCD stack's a great program for CCD cameras (SBIG and the like). It is memory hungry but it's easy to work around this and it does a great job at calibrating using flat/dark/offsets which as you pointed out I didn't bother doing Just testing trying to get some colors at this point.

My feeling though is that the DSLR way might be a dead end and money's best spend in a dedicated CCD camera. Definitely less noise and less stuffing around.