Alignment options

Posted by 7170 on Dec 16, 2020; 9:09pm
URL: http://astroimagej.170.s1.nabble.com/Alignment-options-tp1471.html

Hi, I'm confused about which alignment option is best to use for different scenarios.

I can see the following ways of doing an alignment:

(1) Align stack using WCS
(2) Align stack using apertures
(3) Align stack using image stabilizer

I do two types of work (a) double stars and measuring PA and distance between pairs, and (b) photometry on variable stars (plotting light curves over time).

For double stars I have always aligned the stack using option (2) and then combined them into a single image using average. And for variables I used to align using (2) and then plot the light curve using apertures. But more recently have note done an alignment but used "Use RA/Dec to locate aperture positions" instead.

I am however wondering if this is an optimal approach for both types of work or not - what do people recommend? One thing I have noticed is that option two does warp the image slightly - namely the x and y pixel scale is usually slightly different after plate solving, yet that is not the case with (1).

Thanks in advance.