Below are some of the most common image stacking software applications available in the field. I have included my opinions on the ones I prefer and why!
I started out using DSS but now use APP for most of my stacking. It is simply the easiest and quickest to use. APP is also brilliant at mosaics and very useful when stacking the multitude of stacked images produced by different scopes from the BAT. However I also use Pixinsight to stack OSC data (aka colour data) because Gary Palmer told me that Pixinsight handles colour data with all its annoying bayer patterns better than both APP and DSS. Apparently Sequator handles colour data very well too but looses out over DSS in terms of sharpness. Pixinsight is extremely powerful but very geeky. I find it is essential for more complicated projects. I’ve used Sequator for some of my widefield milky way shots and timelapses.
For planetary and lunar and solar stacking I use Autostakkert. Tis basically great but data that isn’t great can be quite hard to stack. You might need to clean up your movie through PIPP if autostakkert isn’t working and then try autostakkert again.
I’ve never used SIRIL.