StarTools

I've just started using StarTools. I am attempting to layer RGB and Ha of NGC 6992. The RGB has been cropped, but not the Ha. Both are now saved as .tiffs.

How do I get Ha cropped to align with RGB image so I can merge the layers in StarTools?

Thanks,

DKKDWhite

Hi,

Welcome to the StarTools forum!

The correct way is to use your stacker to align the two stacks during the stacking stage.
To do this, stack the one stack (say the RGB stack) as normal, then use this stack as a reference for stacking the Ha frames.
The two stacks should now have the same dimensions, while being perfectly aligned and rotated.

There are various techniques to integrate Ha into RGB - do feel free to give use more information on the exposure times and goals.

Clear skies!

Ivo,
Thanks for the welcome and quick reply.

I was attempting to repeat what the author of the You Tube video "StarTools, layering Ha & OIII. Rosette Nebula", had done - layering two different filtered (and stacked) images. In the video, he binned and cropped the Ha and after completing the processing tweaks, he opened the OII, binned and somehow was able to crop this 2nd image to the same coordinates as the first.

I attempted this process for the Veil nebula with RGB and Ha data. I first binned and cropped the RGB and completed the development including star reduction. Then I opened the Ha and binned it. However, when I attempted to crop, there was no "automatic" alignment to crop to the previous image as was seen in the You Tube video. Consequently when I attempt to layer the images they will not align.

Any idea what I'm doing wrong?

Thanks,


Greg

The auto-cropping (remembering of settings) only works (for obvious reasons) when the image is the exact same dimension as the image you cropped previously. If it appears the Crop module is not remembering the offsets, then the image you are trying to crop must not be the same size as the image you cropped previously. Is that the case here?

Ivo,

That may be the case. I saved the original (first file) as a .tiff and closed StarTools. I loaded the original later before starting the 2nd (Ha) image. It appears the .tiff file and closing the program defeats the auto crop feature.

Thanks,


Greg

dkkdwhite wrote:Ivo,

That may be the case. I saved the original (first file) as a .tiff and closed StarTools. I loaded the original later before starting the 2nd (Ha) image. It appears the .tiff file and closing the program defeats the auto crop feature.

Thanks,


Greg

Ah, yes. The cropping info is not stored between sessions. The StarTools.log file will have recorded the parameter settings however, if you need to reference them.