With the PST etalon acting as an internal module, the sweat spot issue becomes more serious.
On processing some of the newly acquired shots, I found that the images simply cannot be stitched together, and part of the reason i found is that, the image quality on one side is different than the other side, one side is contrasty, and one side is blurred.
Seems like this should be taken care in order to make mosaic. The simplest way is to allow more overlapping between frames, and cut off the blurred part.
Let's see how to move on. Any new equipments, despite they could make you more powerful, have a learnng curve with it. Once overcome, the true power can be unleashed!