The goal of image registration is to re-map each image on the same grid. The reference system, or common grid is usually one of the image. The output of this procedure will be a FITS image interpolated on the reference grid.
This procedure involve 2 steps:
- Getting the astrometric transform, X=f(x_ref,y_ref )
- Making image interpolation (Bicubic Splines)
This is the main program, and the core of the new method presented in the 2 papers. Before you run the code, you need to make a good reference image by stacking some of your best images. Then you can use the image subtraction code to adjust the reference image to the seeing of each individual image (which have been previously registered and interpolated).
The image subtraction code can process the whole frame by small pieces, it is especially useful in case of large images which can be processed with limited memory ressources.
The code has 2 level of rejection
for variable objects:
- Checking that each individual star does not show flux variations
- Checking the chi-square for each individual star
The final output of the code will a subtracted image of the flux variation beween the individualimage and the reference frame.