Jeezz, ask and you shall be answered. Really appreciate the info being provided.
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Originally Posted by dcalleja
Jase
It looks like a Hubble image, really sharp detail in the head and surrounds. I use CCDStack but really am a novice at it so I bought the DVD from Adam Block and I dip into it when I get stuck (often). I get frustrated with the tool though as it runs out of RAM frequently even on a 4GB laptop - unlike some other tools it stores all the images in memory and can really slow down. If you haven;t already done so you can take the memory warning off in SETTINGS - I find it really annoying to have my workflow disrupted every few minutes.
I;ve not done too much so far with deconvolution so good luck
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Cheers Dan! I guess like all new things, it takes time to get use to it. CCDStack is no exception. Yes, I've heard of the memory issues, however I've not experienced this...I am running it on a high end vista64 workstation would helps. I may get hold of Adam's DVD to accelerate the process. Thanks again for your comments.
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Originally Posted by Martin Pugh
Hey Jase....great shot and great processing. I would love to have a 20" RC at my command one day!
Without checking, did the FOV of the 20"/STL limit the field? It would have made for an exceptional shot to have included NGC 2023....Adam Block's APOD of IC434/NGC 2023 was taken with a 20" RC I believe (albeit from Mount Lemmon)...and that is truly spectacular.
CCDSTACK - I never use more than 30 iterations when deconvolving and after many, many tries and experimentation, I can fairly safely conclude that the RGB creation/result is below my critical standards.....so I dont use it for that purpose...in fact, even with the new CCDIS plug-in, alignment often fails....and I mean often....you have to zoom and blink to see it, but it remains inferior to something like Maxim.
CCDStack will chew up memory and bog down any normal PC....I stopped using it, fed up with constant VM problems and dreadfully slow processing.....however, I now have a 64bit Vista PC with 8GB of RAM, and its operation is awesome. I can now have 20+ 41Mb images open, and it doesnt care, and I often run two deconvolution routines simultaneously, each with different settings to compare results.
Well done mate
cheers
Martin
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Thanks Martin.
The FOV of the 20"/STL is what is presented (be it reduced in size (but it only slightly cropped). Its rather narrow. Indeed, capturing NGC2023 would have perhaps completed the overall scene, but Alvin decided to frame it differently to accentuate the long curtain type Ha structure behind the HH. Adam's image was taken with a 24" RC. Its a really nice image of the area. I've actually got the raw data and processing tutorial of this image which I picked up at AIC. Pretty cool to play around with. The data actually has a massive reflection going straight through the HH in which he did a remarkable job of resolving.
Thanks for the information on CCDStack. Interesting experience with the new plug-in. I can't say I've had any issues to date, but it is still limited if you trying to match data at vastly different focal lengths. Registar is still a cut above for this type of work. You've got me thinking whether I should go back to MaximDL for certain functions i.e. colour combine etc. Will do some investigation. I'm still in envy of your tight stars...something which can be difficult to deal with due to seeing or general use of broadband filters. Ha always delivers tight stars, so it great to simply use them in the blend process. Thanks again for the info. Seasons greetings!
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Originally Posted by gregbradley
Love it. Superb processing as usual.
As Martin mentioned it would have been nice to capture that beautiful little blue neb with the bits of pink streamers in it.
As far as CCDstack I use it and have for some time. I like the way it follows the work flow of processing an image. Martin is correct its memory programming is crapola deluxe and Stan would do well to get a copy of Images Plus and see how it handles memory so well.
With regards to normalising the RGB before combining, my experience is it depends on which brand filters you are using.
When I used Astrodons I didn't use it and using it seem to worsen results.
When I use Astronomik or Baader filters I sometimes use it when I get an odd/off colour combine and it corrects it. So for me it depends on the result of the colour combine if I get odd results or if it looks fine.
I have normally used 1:1:1 combines and that worked fine. Again Marcus probably is being more hi-tech than me and it would depend on the camera and the filters on how close they are to a 1:1:1 combine. Astrodon and Baader market on the basis that they are 1:1:1 and they seem to work out that way on a practical basis. Any slight difference is picked up when doing your Photoshoping anyway.
I always normalise luminance (not renormalise if there is such a thing - normalise means to make the bright and dimmer areas into a similar range so sometimes it can make say a dim green sub too bright if you got less exposure time with one colour due to clouds). I don't know if it really is that important though. Probably more so if the subs varied a lot in quality due to clouds or dawn or some such otherwise if they are much the same I wouldn't expect it really does virtually anything.
I don't use deconvolution too much as it oftens gives a vey harsh result. I suppose it is a tool to use lightly and not get too caried away with it. Certainly not the 100 iterations it seems to be set for as default. Perhaps more like 10? Not sure which one works better and under what conditions - the 2 types of deconvolution in the program.
That new align tool in CCDstack though is absolutely a gem. It does such an incredible job and seems to not be slow like Martin points out it has been in the past (plus the standard program's auto align virtually never works except on really small files).
As far as saturation in CCDstack I tend not to use it as I feel there is more control in Photoshop but occassionally I have increased it if the image looked a bit pale.
More importantly save your final image as a TIFF and RAW not scaled. Scaling will cause you to lose some control. Far better result to save as a RAW and then use curves/levels to bring up your image moving the black point as needed to reduce the noise and get your bell shaped histogram.
Also watch CCDstack DDP it seems defaulted to slightly black clip. It may pay to be selective when using it and not use the auto button too much.You'll end up with a histogram not bell shaped and too hard to the left.
Cheers,
Greg.
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Thanks Greg. Excellent information. Renormalise is simply running the normalise function again. Some believed it could or should only be ran once, but this isn't technically correct. As you indicate, it doesn't alter the data, but the weights for each sub compared to each other in the stack. I'm still playing with deconvolution. I do both heavy and light reditions and blend them in giving you greater control over where you want the details. Thanks for the info on DDP black clipping. Never used it for a permanent data altering function as yet, only screen stretches. I like MaximDL's DDP functionality and use to it so will stick with what I know there. Thanks again and seasons greetings!
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Thanks all. Have a good one!
