DSS vs Nebulosity vs ???

[gminder]

Ivo,

Your recent exchange with gboulton in the "getting rusty" thread was very interesting. I have DSS, Nebulosity and a trial of PixInsight. I've just about given up on DSS. I was really hit and miss with DSS until I recently got a Baader mod on my 450D. Now I can't get a good image out of DSS to save my life and I just don't have the time or patience to figure out which DSS setting(s) to tweak.

I am using Nebulosity with great success. My first modded 450D pic (Wizard Nebula) is below. Full res at http://www.astrobin.com/full/51157/?mod=none

For Nebulosity I am using the workflow at http://www.morrell.ws/index.php?option= ... &Itemid=42

I would actually prefer to use DSS if I could get good results from it. It's a lot easier than Nebulosity's multiple steps. In the previous thread you mentioned developing a guide for using DSS to get optimal results in ST. I for one would love to see that. If you use Nebulosity I would also love to know what your work flow is. And I would second gboulton's comment about a Star Tools module for pre-processing!

If you look at the Nebulosity work flow you'll see that after stacking, there are steps to neutralize the background and auto-balance colors. Based on your comments in the other thread, can I assume that you would recommend that I skip those steps if I intend to use Star Tools?

Wizard Neb PreProc with Flats & Bias_Color Cal_ST Proc_Done_Reduced for Web.jpg (239.61 KiB) Viewed 22018 times

[admin]

That's a nice image!

I would actually prefer to use DSS if I could get good results from it. It's a lot easier than Nebulosity's multiple steps. In the previous thread you mentioned developing a guide for using DSS to get optimal results in ST. I for one would love to see that.

I did manage good results in the end with 3.2.2 (still doing some tests), but it involved using the very latest version of dcraw to pre-convert the RAW files.
If anyone is interested, the following finally got me virgin, non-whitebalanced frames;

Code: Select all

dcraw -v -r 1 1 1 1 -4 -T -S 32767 -k 0 -o 0 *.CR2

If you use Nebulosity I would also love to know what your work flow is.

Maybe we could involve Craig Stark in this - I've had similar trouble with Nebulosity as well.

And I would second gboulton's comment about a Star Tools module for pre-processing!

Noted!

If you look at the Nebulosity work flow you'll see that after stacking, there are steps to neutralize the background and auto-balance colors. Based on your comments in the other thread, can I assume that you would recommend that I skip those steps if I intend to use Star Tools?

That's correct - keep the data as virgin as you possibly can.

[gboulton]

Gorgeous image, gminder!

I was really hit and miss with DSS until I recently got a Baader mod on my 450D. Now I can't get a good image out of DSS to save my life and I just don't have the time or patience to figure out which DSS setting(s) to tweak.

Wanted to pick this statement out and "second" it if you will.

When I removed the IR filter from my 450D, any ability of DSS to stack usable results went right out the window. After the first few tries, I've simply left it in its case, and gone back to using my 1100D...which is a fine camera, but I was certainly hoping for better results from the mod.

I think, now, in light of learning to integrate and calibrate with PI, I'm going to take the 450 back out and give it a couple of runs. I have renewed hope that I'll get some enjoyable results from it.

I would actually prefer to use DSS if I could get good results from it.

Indeed...but I've come to the conclusion, given the issue above and in light of my conversation with Ivo and the experimentation we've done there, that I simply no longer have room for DSS in my workflow.

There's just to many instances of data that's either virtually unusable...or that bears no resemblance to previous or future efforts. It's both inconsistent, and at times, incompetent. Bluntly...I'd fire anyone who worked for me that delivered similar results, so...I'm firing DSS.

[admin]

I've been able to produce decent result with DSS and it core stacking and registration routines seem fine and capable (for my purposes anyway...). It's the debayering stage (downright defective), post-processing (destructive when you let people save the result), logic (not respecting settings), file handling (flaky) and UI (not saving states) around it that is messing things up badly.
Using dcraw as an external tool to pre-process the data helps tremendously, making stacking and registering a matter of a few clicks. It doesn't help that new users can only download the - rather crippled - 3.2.2 version while there are apparently newer 'beta' versions out there that work a lot better than the 'stable' version.

As for filtered frames, there should be no reason why DSS cannot handle them. What sort of results did you guys get?
Correctly white balancing filtered data is impossible though, however there exists a workaround (see this thread on CN).

[AndyBooth]

I did manage good results in the end with 3.2.2 (still doing some tests), but it involved using the very latest version of dcraw to pre-convert the RAW files.
If anyone is interested, the following finally got me virgin, non-whitebalanced frames;
CODE: SELECT ALL
dcraw -v -r 1 1 1 1 -4 -T -S 32767 -k 0 -o 0 *.CR2

Ivo, this is very interesting, I immediately got better results using this pre procress.
How do you handle calibration using this?
do you pre-process all the flats darks etc and use dss on the resulting tif's? as normal?

Regards,
Andy

[admin]

I did manage good results in the end with 3.2.2 (still doing some tests), but it involved using the very latest version of dcraw to pre-convert the RAW files.
If anyone is interested, the following finally got me virgin, non-whitebalanced frames;
CODE: SELECT ALL
dcraw -v -r 1 1 1 1 -4 -T -S 32767 -k 0 -o 0 *.CR2

Ivo, this is very interesting, I immediately got better results using this pre procress.
How do you handle calibration using this?
do you pre-process all the flats darks etc and use dss on the resulting tif's? as normal?

Regards,
Andy

Great to hear this is working for you Andy!
Yes,you're spot-on! Just process all your flats/darks/bias/etc. CR2s in the same way.
If all is well DSS will produce a nicely calibrated (and non whitebalanced) stack for you to import into StarTools.

[JMorris]

When I enter dcraw -v -r 1 1 1 1 -4 -T -S 32767 -k 0 -o 0 *.CR2 in the command prompt of my Windows 8.1 machine all I ever get back is:

*.CR2: Invalid argument

The conversion works fine if I write out the very lengthy filenames but I don't relish having to do that for all the lights, flats, dark flats, darks and bias frames. I could probably write a python script to automate the process but I'm thinking there must be an easier way. Is there? (I'm somewhat computer savvy, but the things I don't know far exceed the things I do.

By the way, the converted files come out vertical (portrait mode) when they started horizontal (landscape mode). Is that normal?

Jim

[admin]

When I enter dcraw -v -r 1 1 1 1 -4 -T -S 32767 -k 0 -o 0 *.CR2 in the command prompt of my Windows 8.1 machine all I ever get back is:

*.CR2: Invalid argument

The conversion works fine if I write out the very lengthy filenames but I don't relish having to do that for all the lights, flats, dark flats, darks and bias frames. I could probably write a python script to automate the process but I'm thinking there must be an easier way. Is there? (I'm somewhat computer savvy, but the things I don't know far exceed the things I do.

Hmmm.... that's odd. Are you using a recent version of dcraw? I can compile one for you if needed...

By the way, the converted files come out vertical (portrait mode) when they started horizontal (landscape mode). Is that normal?

Make sure that the resolution of the output is actually correct. Some older versions of dcraw have a bug where the data is incorrectly converted and the image gets 'squashed' in horizontal direction (in addition to other problems).

[JMorris]

Hmmm.... that's odd. Are you using a recent version of dcraw? I can compile one for you if needed...

I think the version I'm using is the most recent: version 9.20. Thanks for the offer though.

Make sure that the resolution of the output is actually correct. Some older versions of dcraw have a bug where the data is incorrectly converted and the image gets 'squashed' in horizontal direction (in addition to other problems).

Yes, the output resolution is the same, the photos are just rotated 90 degrees, but not, as it turns out, on all of the pictures. Judging from the pictures that get rotated, I think it might be using the in-camera orientation feature, though I turned that off to make my astrophoto work easier.

I can't do it right now but I'll have to try dcraw on my Windows 7 machine to see if the *.CR2 works there. I wouldn't be surprised to learn this was just a quirk of Windows 8 (or 8.1)

I did write a quick and dirty little script to do the batch conversions for me though.

Thanks for your speedy response!

Jim

[admin]

Ok, cool. I'm having best results with 9.17 - a later version introduced a bug (can't remember the issue exactly... ).
Very odd about the wildcards not working...
Does the option '-t 0' (flip image = none) help with the auto rotate?