Newbie to LRGB and Hubble Pallette Photography

Questions and answers about processing in StarTools and how to accomplish certain tasks.

Newbie to LRGB and Hubble Pallette Photography

Postby astronomynut » Sun Nov 27, 2016 11:16 pm

I haven't quite gotten the bugs out of my system yet when it comes to the software working with the hardware, but I eventually hope to start imaging with my new camera, a ZWO ASI 1600MM Cooled.

That tells you that I haven't gotten to processing yet> The problem is I haven't found anything that will get me a road map of how to take the various FITS files I will have to take, combine them in DSS, then import them into Star Tools.

Does anyone know of an online source that takes the beginner from basically taking all the required subs (lights, flats, bias and darks), then processing the bulk data with DSS. I would need to know the settings in DSS before it processes that data.

Then how you upload the processed DSS data into Star Tools, and get the LRGB or the HSO, or combination of all seven to create one piece of data that can be processed.

What is the best way to start? Should I just take say HA photos for a while to learn how to process that?

Needless to say, I am lost, as I have only imaged with DSLR's for about three years, and not done all that well when it comes to processing. At least that is my own opinion of my work.

But any help pointing me to where I can read or watch a video would be helpful. Videos that speed through the processing, and don't explain what is going on, are virtually useless to me. I need something that is virtually step-by-step in order to understand what is going on.

Caley Ann
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Re: Newbie to LRGB and Hubble Pallette Photography

Postby admin » Fri Dec 23, 2016 5:40 am

astronomynut wrote:I haven't quite gotten the bugs out of my system yet when it comes to the software working with the hardware, but I eventually hope to start imaging with my new camera, a ZWO ASI 1600MM Cooled.

That tells you that I haven't gotten to processing yet> The problem is I haven't found anything that will get me a road map of how to take the various FITS files I will have to take, combine them in DSS, then import them into Star Tools.

Does anyone know of an online source that takes the beginner from basically taking all the required subs (lights, flats, bias and darks), then processing the bulk data with DSS. I would need to know the settings in DSS before it processes that data.

Then how you upload the processed DSS data into Star Tools, and get the LRGB or the HSO, or combination of all seven to create one piece of data that can be processed.

What is the best way to start? Should I just take say HA photos for a while to learn how to process that?

Needless to say, I am lost, as I have only imaged with DSLR's for about three years, and not done all that well when it comes to processing. At least that is my own opinion of my work.

But any help pointing me to where I can read or watch a video would be helpful. Videos that speed through the processing, and don't explain what is going on, are virtually useless to me. I need something that is virtually step-by-step in order to understand what is going on.

Caley Ann


Hi Caley Ann,

Narrowband imaging is a broad topic, but you already make a good point; try Hydrogen Alpha first.
This will give you an idea on how to proceed with your specific setup. HA is a good way to get into narrowband as a lot of objects emit it in abundance (less so for S II, O III or N II). You will quickly figure out what works and what doesn't.

I would stick with DSLR or HA imaging for a while, if you're not yet comfortable with acquiring and appying flat frames, until you are, before trying to do the same for multiple bands.

Good data acquisition skills are the cornerstone of a good image. Good data will make your live infinitely easier when doing the post-processing.

Best of luck!
Ivo Jager
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Re: Newbie to LRGB and Hubble Pallette Photography

Postby astronomynut » Sat Jan 07, 2017 7:42 pm

Thanks for your reply. I apologise for not answering sooner. I am still working the bugs out of my setup. I finally got everything except auto focus set up, though I am still trying to learn all the ins and outs of SGP.

That said, I finally acquired my data on NGC 1893. I have all the lights, darks, flats and bias for the LRGB. I am assuming that I need to load each data set and process it through DSS. That will give me one FIT for each colour (LRGB). Didn't do Ha. I haven't had good enough skies to get that. Took me a month just to get this one object

Once I do have those four FITS files, just how do I go about running them through Star Tools. I notice up at the top of the start, that there is a box LRGB. I am assuming that you press that, and it prompts you to upload a file, or all the files. I haven't tried yet. I am kind of hesitant because I haven't found any information on how to process these four files into one file, and then create a photo. Is there a reference online that I can look at to get me started? Caley Ann
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Re: Newbie to LRGB and Hubble Pallette Photography

Postby ChrisLX200 » Sat Jan 07, 2017 10:08 pm

astronomynut wrote:Thanks for your reply. I apologise for not answering sooner. I am still working the bugs out of my setup. I finally got everything except auto focus set up, though I am still trying to learn all the ins and outs of SGP.

That said, I finally acquired my data on NGC 1893. I have all the lights, darks, flats and bias for the LRGB. I am assuming that I need to load each data set and process it through DSS. That will give me one FIT for each colour (LRGB). Didn't do Ha. I haven't had good enough skies to get that. Took me a month just to get this one object

Once I do have those four FITS files, just how do I go about running them through Star Tools. I notice up at the top of the start, that there is a box LRGB. I am assuming that you press that, and it prompts you to upload a file, or all the files. I haven't tried yet. I am kind of hesitant because I haven't found any information on how to process these four files into one file, and then create a photo. Is there a reference online that I can look at to get me started? Caley Ann


The LRGB option in StarTools is indeed the tool used to combine the individual channels into a colour image, however before you get to that stage you need to have done some pre-processing of the data. Each set of subs needs to be callibrated and stacked together into a single master file and these aligned ('registered') with each other. StarTools does not have the capability to do that - but DSS does. In DSS you need to select just one file from one group (usually the Luminance group) and, after loading all the Lum subs into DSS, right-click on that file and choose 'Use as Reference Frame'. Load all the calibration files too - flats, bias, darks..(just drag and drop from Windows Explorer into the DSS window and DSS will ask you what type of files they are) then click Register (and optionally, also stack them in a single operation). All the subs will be aligned to that one reference frame and the lights stacked together to produce the master Luminance - and automatically saved as 'Autosave.fit'. I suggest you rename that at this stage (Lum.fit would be good :-) ).

Now - the trick - for the next channel (say, the Blue channel) - close DSS and then open it again afresh, then load all the Blue lights and the relevant flats for that channel (and darks and bias of course). Also, load the single Luminance sub you had chosen as the Reference frame (so you needed to remember which one that was!). You will have a list in DSS of all your Blue lights and the single Luminance sub - check by right-clicking on it that the Luminance sub is still set as the Reference frame. Now choose Register from the box to the left in DSS - but ensure the Stack option is not enabled at this stage. DSS will align all the Blue subs with that single Luminance Reference frame. Now un-tick (deselect) the Lum Reference frame and then choose 'Stack Selected Frames' in DSS. This will ignore the un-ticked Reference frame and stack just the Blue subs thus creating a master Blue channel which have all been aligned with the master Luminance sub, and save that (also named Autosave.fit unfortunately - you have to remember to rename them!).

You repeat this process for Red and Green channels (and any other narrow-band channels you have) and when finished all the master stacks are already registered with each other and nothing further needs be done in that regard. Had you NOT done it this way, and just stacked each individual channel without using the single Reference frame, you would need to register the master channels with each other as a separate task, easy enough if you have another processing program capable of doing that (PixInsight, AstroArt etc.,) but not so easy if you don't.

At this stage you could go right ahead and combine the files in StarTools using the LRGB tool to select each master channel, they will all be aligned and will give you some sort of result which you can continue to process in StarTools. In reality it would have been better to perform some other pre-processing before you do this - normalise the background levels between each of the RGB channels for example, and perhaps adjust star sizes so they're approximately similar if one of the channels (often Blue) shows evidence of 'bloat'. If you have a Luminance channel then this is good because that channel will be providing all the detail information for the final image. This channel you can process on its own using StarTools prior to combining with the others. It's an optional step, but you can use all the tools StarTools offers - sharpening, deconvolution, noise reduction and so on on this channel first. There are of course many ways you can approach this task, with just RGB channels (i.e., no Luminance channel) I do a minimum amount of processing prior to combining into a colour image and then post-process as a colour image. For LRGB I process all four channels and then combine, final tweaks being applied to the final colour image. For narrow band I always process each channel independantly and the final steps are channel combination and colour balancing. There is no fixed methodology - use the strategy you find works best for you.

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Re: Newbie to LRGB and Hubble Pallette Photography

Postby astronomynut » Sun Jan 08, 2017 2:54 am

Chris, Wow!, that's quite a bit to chew on. Thanks for taking the time to talk about the process. I will try to follow the steps you put forth. I am still pretty flaky with my processing of DSLR photos. I did process the "L" part of the LRGB data I got, and I post the result here. Was my first, so it is probably pretty bad. The object is NGC 1893. It's only a 10x120 seconds photo. I am still tryiing to get all my software and equipment to cooperate with each other. Caley Ann
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Re: Newbie to LRGB and Hubble Pallette Photography

Postby astronomynut » Mon Jan 09, 2017 12:47 am

Today I used DSS to align my LRGB data as given by Chris. Doing all the work in DSS, while time consuming, was fairly easy.

Next I loaded the "L" autosave fts into Star Tools. I then tried to load the "R" autosave fts data, but Star Tools said the size was not compatible, but a different size. The fact is that all four of my files have the same dimensions, so some other problem is entering the picture. I am wondering if it is possible that the artifacts on the edge of each of the LRGB photos is causing problems.

I remember someone telling me that this can happen, and the only way to cure Star Tools from rejecting the photo is to crop all of them to the exact same size. Does anyone know how to crop a fts file so that all four have the exact same dimensions? I am guessing you need to choose a bright reference star, and map out just where you want to crop. I don't know of any program that will do that for you.

So for now, I am stuck with this data which I cannot put together because Star Tools is seeing each of the LRGB photos as different dimensions, even though they came from the same camera. I did not do any binning. All the data is 1x1.

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Re: Newbie to LRGB and Hubble Pallette Photography

Postby astronomynut » Mon Jan 09, 2017 4:26 am

I used Star Tools to do my preprocessing.

I uploaded my RGB, and discovered that my camera had rotated about 10 degrees. This apparently created an over sized image. My "L" frame was fine, which was the first thing I took in the data accumulation.

I figured I might be able to rotate and crop all of my data to one size with the tools in Star Tools. But I discovered that in order to do this, I had to "Autodev" in order to see what I was doing. Rotating went fine, and after some trial and error, discovering how the crop actually works, got all my data cropped to the same dimensions.

I saved the files, but they were saved as TIFF. I then loaded the files into the LRGB section at the start, only to discover that something strange had happened to my data when they were stacked together with Star Tools. I got what you would get if you fixed your camera on Polaris, and took an extended exposure. But the stars were stacked properly. It was something else that created this circle effect.

So I think I will have to just trash the RGB data that I have, and be happy with the Lum data. I will try another experiment on another object and see if I can get all the data oriented one way. Hopefully Star Tools won't be picky if there is a tiny bit of rotation.

Another problem I think might have caused problems was the fact that I didn't know how to change the filter manually in SGP while getting this data. Consequently, I was focusing with the Lum filter each night, then upon initiating the sequence, the filter was changed to the filter I wanted. It looks like my focus was soft in the RGB data, even though I got a sharp focus with the lum filter.

So I am back to step one. I will come back for help if the new data gives me problems. Caley Ann
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Re: Newbie to LRGB and Hubble Pallette Photography

Postby Notty » Tue Jan 24, 2017 11:04 am

I'm in exactly the same boat as you, just moving up from DSLR to the amazing 1600MM with full set of LRGB and NB. I'm starting a thread with my own issues I've come up against, like you I'm fighting on two fronts with the capture and the processing, but I'm enjoying the learning curve. I'll follow your progress!
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Re: Newbie to LRGB and Hubble Pallette Photography

Postby astronomynut » Fri Jan 27, 2017 11:54 pm

Notty, Good luck with your photographic endeavours. I've looked at photos taken with the ASI 1600MM camera, and am awed by the quality it provides.

I took a set on one object, but it seems my camera rotated between the sessions, causing the size of the photos to not be compatible. I tried cropping, which was a real chore, eventually getting all four sets the same size. Unfortunately something else was wrong with the data, and nothing came out when I tried to enter the raw TIFF's into Star Tools.

Someone, somewhere, which I can't seem to remember, said that he takes each data set, and processes them separately. Then he stacks the results together, and does a final processing. I still have yet to figure out how to do that.

Onto another subject. Is there a way to crop the FITS data for each data set (LRGB), and still keep them as FITS data. Or are you stuck with the conversion that Star Tools burps out, TIFF?

I have a favour to ask of someone who reads this thread; someone who does LRGB or narrow band photography. Is it possible that you could post your work flow for a data set so that I can try it out, just to start getting used to how things are done. After I get used to that, I can then start branching out, experimenting as I go, just as I have with my DSLR data.

Fore now I am out of the photography mode until I get back to a bit better health. So, right now I have been revisiting my DSLR data, and improving on the results. I hope to possibly obtain data somewhere, where I can practice with someone else's LRGB or narrow band data to get some practise for when I finally get back to data gathering.

Thanks in advance

Caley Ann
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Re: Newbie to LRGB and Hubble Pallette Photography

Postby Guy » Tue Jan 31, 2017 4:52 pm

When you were doing the stacking in DSS - what mode did you select in the 'Result' tab of the Stacking Parameters?
Choosing 'Standard Mode' will ensure the stacking process is framed by the reference light frame you chose.
If you didn't choose this mode I think the results may be variable - so it may be worth a try restacking using this setting.

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