Problems with preprocessing of spectral images

[Forum_2017]

Hello,

for quite a while I've tried invain to stack my spectral images correctly. I hoped, that the situation had been improved with AA6, but it did not. When stacking my images via Preprocessing -> Align -> Auto Alignment -> Spectrum, some times several images out of a measuring set are stacked correctly, while the others "jump" over many pixels or produce "error" messages. It doesn'nt matter if the spectra are faint or have a high S/N ratio, nor if the selected region is large or small. The only alternative is to stack manually, which is not very comfortable (sometimes over 100 images!) and of course lacks the precision of sub-pixel stacking.

Any help is highly appreciated...

[Forum_2017]

Hello,
the selection of the absorption line and the size of the rectangle search is critical, the only solution may be to send me 4-5 images to evaluate the problem. I suggest: the first image, a correct align, then 2-3 images which are not aligned.
Fabio.

[Forum_2017]

<name?> I've been using AA for many years, and for the past ten years have been using it for my spectroscopy.
It does all my light/ dark/ flat pre-processing and stacking. Fabio has been very responsive to our needs....
I can only assume your images are grating slit-less images (??) stacking a 100 subs seems excessive....
If you can supply some samples of the good and bad subs (kenm(dot)harrison(at)gmail(dot)com ) I can certainly have a good look at them and hopefully make some recommendations.

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