Alignment of many images with Dynamic Alignment

[fgasdia]

Some of the images I work with need to be registered and integrated, but can't take advantage of the excellent star alignment tool. An example of this is images of a cluster of geosynchronous  satellites. If I am "tracking" on the satellites, stars will drift over a few minutes of imaging but the satellites will be roughly in the same place. Assuming I have many (100 or more) images, is there a tool (perhaps a variation on Dynamic Alignment) that would allow me to select the objects to align on in a reference frame and then automatically do a fine image registration of the other images?

I've just spent an hour manually using dynamic alignment on 120 images and I never needed to correct it's guess at where the object was in the target frame. I'd prefer not to do this manually again if I don't need to.

[msmythers]

Hi

I don't know that I can help you but I'm trying to understand what you are trying to do with say something like tracking a satellite. So the sat is in the center of the images? Are you trying to align all the images to the stars or the satellite? If to the sat then you're expecting star trails??

I did a very simple test with the Catalog Star Generator. I generated 4 star fields that changed slightly in RA and Dec. I then placed a white rectangle in the same spot in each image. I did 3 different alignments.

The first is simply adding each image to the next with PixelMath. The rectangle stays in the center. The stars would normally be trailing if I had smaller RA and Dec movements and more images.

The next was a mosaic method based on the images already being plate solved. I used Mosaic By Coordinates and Gradient Merge Mosaics to generate the image from the 4 original images. This shows the whole star field and where the rectangle traveled through the star field.

The last is using StarAlignment and aligning each image to a reference star field, 'CatalogStars'. I then used ImageIntegration to form the final image. This image shows the track of the rectangle through the reference image.

If there is another output you are looking for I'm not sure what it is. The only one of the three outputs that might require you to work with each individual original image is the the mosaic method. That would be if your images are not plate solved before bring them into PixInsight. However if your capture software does save the images in fit format and does embed the coordinate information then you might not need to plate solved(ImageSolver).


I hope I haven't muddy the waters as such.



Mike

[Alejandro Tombolini]

Hi,  Could it be done with Comet Alignment module?

[fgasdia]

Mike: Thanks for the suggestions. Yes, I'm hoping to stack on the satellite and have star trails. The problem with the simple PixelMath addition is that in my data the satellite isn't perfectly centered, it moves by a few pixels.

I realize this is a somewhat awkward task. To fully register the image would require 3 or 4 reference points and I usually only have 1 or 2. This limits the registration to only an image shift.

I might see if I can write a JScript using the Dynamic Alignment tool to do what I need.

Alejandro: I'll take a look at it, but my concern is that it's overly complex.  The goal is something that I can perform photometry on -- not something that looks good. Several images will be stacked to increase S/N,  then another several stacked again, and so on. Photometric analysis will be performed on each of these "master" lights.