stacking two fits images in Siril

[bottletopburly]

Can i stack and align two fit files in siril if so how ,can someone tell me step by step i usually use scripts in siril and find the manual process in siril complicated .

[speckofdust]

I am not an expert, but when I used it recently, it gave me very good results for the same process that ended up with hot pixel trails in deep sky stacker.

This is the process I follow:

You need to put all your images ( light frames, darks and flats in separate sub folders named "Lights", "Darks" "Flats"- the names should be exactly those, otherwise it wouldnt work) in one single folder . 

Then head over to siril, use each of the tabs in sequence--File conversion, sequence, pre-processing etc..

While in file conversion, select the "change directory" button and select your "Lights" subfolder. Then click on "Add" with the plus sign that is to the right of the source box and add the files. If you have colour Light frames, add them all in one go and give a sequence name eg: light and then click convert. If you have separate R, G and B subframes, only add the individual channel frames and convert them under separate sequence names. Also do the same for your darks and flats. Once this step is complete, move onto the next tab- Sequence. You select all of the sequences generated in the previous process one by one and give a name and click "export sequence". before you do that you can reject the frames that you dont like by viewing them individually in the viewing window that would appear.

next move onto Pre-processing tab. here you can choose your master dark and flat files and pre-process your sub-frames

then move onto registration- fairly straigtforward process.

Then plot- here you will see how your frames are differing in quality from the median line. Keep the median quality number in mind

Then move onto stacking- you can either stack all your subframes or a smaller set. You can use the + or - symbol next to the "stack this set of images" to choose the number you want to get as close to the "median quality number " from the previous "Plot"tab. and then click start stacking which will give you the final stacked images for R, G, B etc

There will be a number of options to choose within each of the tabs, but the good thing is that if you hover your mouse cursor over the options, there will be very clear explanation to guide you, so with some trial and error it should work.

Having said all that I did not get good results when I pre-processed with dark and flat images- absolutely no idea why that happened, so I stacked without the darks and flats and got way better result than with DSS ( with dark and flat). May be I will figure it out one day or someone here can help.

 

Edited October 25, 2020 by speckofdust

[speckofdust]

Obviously you already have the subframes as fits files, so you can omit the file conversion step.

[bottletopburly]

1 hour ago, speckofdust said:

Obviously you already have the subframes as fits files, so you can omit the file conversion step.

Thanks all I need to do is align two fit files one is ha and one red I want to merge into one file if possible to create a new red file containing ha data .

[speckofdust]

1 hour ago, bottletopburly said:

Thanks all I need to do is align two fit files one is ha and one red I want to merge into one file if possible to create a new red file containing ha data .

oh ok, afaik,  those files will have different pixel content, hence I dont think you can stack them. You can however use an image processing software such as adobe PS or GIMP to overlay them.