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How to make stack same dimensions as subs?


(@brendanc)
Main Sequence Star Customer
Joined: 2 years ago
Posts: 33
Topic starter  

Hi,

I've come up against a problem (for me, at least).

When I used DSS, it would always produce a stack that was the same size as the subs. This was really convenient, because I could pull them into my post-processing software (StarTools) and be confident that whatever I binned, would bin to the same dimensions, and work together in whatever other package I also used eg Photoshop.

APP however, produces differently sized stacks, because it includes all the edges of all the subs. They're always larger than the subs, and not consistently the same size. This is really inconvenient.

So, is there any way to get APP to produce a stack that has the same dimensions as the subs used to create it? Or, at least, the sub that is used for registration?

Thanks, Brendan


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(@col)
Red Giant Customer
Joined: 1 year ago
Posts: 111
 

@brendanc

APP can of course do this if a cropping step is inconvenient. Choose crop instead of full to mimic the scenario of overlapped areas only in dss, or choose reference if you want the stack to match the reference frame. This second option might include regions as part of dither variations, but crop option drop down in the integrate tab will give you what you want. 


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(@brendanc)
Main Sequence Star Customer
Joined: 2 years ago
Posts: 33
Topic starter  

Ah, got it - under Composition, right? Thanks!

Now, if only APP offered a means of saving the defaults so I didn't have to select this every time...


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(@mabula-admin)
Quasar Admin
Joined: 5 years ago
Posts: 3099
 

Hi @brendanc & @cwm2col,

Indeed, you can control this behaviour with the composition mode in 6) Integrate. If you want to have the dimensions in the stack the same as the reference, choose reference for composition.

I think however that you will lose data that way ? Why is it important not to have the full field of view of all your data like APP does with the default full composition mode? I never use reference mode, always full or crop, crop is really usefull if you need to test drizzle setting in a small object in te field of view.

Finally, If you have a batch of results in APP that are all registered to each other, you can always use the Batch Crop tool to get the data that you want to preserve in the end. The Batch Crop tool ensures that all data then keeps equal dimensions and stays registered.

Mabula


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4690
 
Posted by: @brendanc

Now, if only APP offered a means of saving the defaults so I didn't have to select this every time...

This should be addressed in the upcoming version


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(@brendanc)
Main Sequence Star Customer
Joined: 2 years ago
Posts: 33
Topic starter  

Hi Mabula,

Thanks for this. The main reason is that I use StarTools for post-processing. When I import an image, the workflow is dev, then bin, then crop. This makes sense - the dev enables me to see what I'm doing as a temporary stretch, and if I crop before binning, I'll have differently sized images.

If my images are the same size to begin with, it's all very easy. If not, then it's very difficult! Binning differently sized input gives differently sized output, which is then a nightmare to work with generally.

I accept that by using 'reference', I'll lose some data, but I'd lose it anyway if I'm only selecting the overlapping data. 

It's academic anyway: I get an error message when trying to use reference, see attached file. I'm trying to use just one sub from another session, to align Ha data from my latest session. They are very similar FOV, except rotation 180 degrees or thereabouts, so I'm surprised this doesn't work. It works fine with 'full' selected.

So, I'm not sure where I go from here! I may just have to crop in StarTools instead.

Thanks, Brendan

apperror

 


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(@col)
Red Giant Customer
Joined: 1 year ago
Posts: 111
 

@brendanc

Hi Brendan, 

APP offers a very good crop tool, manual positioning or definition of exact pixel location on the bottom of the tool. Once cropped with the screen stretch, you can then transfer that process to startools. 

If your ha is 180 degrees to your other stack, little can be done re orientation, but their integration should work. Were the ha and the stack star analyzed and registered with each other before using the rgb combine tool to merge them? That registration is required (I cannot see your error message on my phone). That merged imaged can be cropped for startools then.

If instead your are adding ha raw subs to your other raw subs and processing from scratch all of them together, maybe choose flip xy descriptors in registration tab to deal with large FoV orientation differences. One ha data is registered with other data, by either full integration,  either full or crop should work.

The rgb combine tool likes equal dimensions as far as I recall (maybe someone can correct me if wrong), so integration of all raw data together with flip xy descriptors checked might be the easiest, with crop option chosen in the integration tab giving you the overlapping area to work with.

I dont know the detail of stacks or subs, hope I am not giving misleading suggestion for this particular case. 


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(@col)
Red Giant Customer
Joined: 1 year ago
Posts: 111
 

And one other thing I forgot. The batch crop tool also allows you to crop a bundle of separate stacks to identical dimensions, or at least the largest overlapping similar dimension for images with bif FoV orientation differences. That will help with the stack and ha data combination in rgb combine, as on optiptionkn, the off to startools or whatever else.

 

Edit: I see @mabula-admin mentioned this above


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(@brendanc)
Main Sequence Star Customer
Joined: 2 years ago
Posts: 33
Topic starter  

Outstanding. Thank you both! 🙂


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