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.