For a long time I wondered about the benefits of using a prism along with the Star Analyzer. I decided to set up an experiment in my basement.
I have a 50ft dark basement. At one end, I place a neon test bulb. It was wrapped in foil to trap the light; however, a small hole was added to simulate a star.
At the other end of the basement, I set up Astro Tech 72mm fl ED refractor in an uncollimated arrangement. I used an ASI 174MM (monochromatic) camera. I attached a Star Analyzer (100l/mm), with and without a prism, and took many FITS images. Flat fields and dark frames were also taken.
The images were processed with Astro Art.
The only processing done was to average all frames and correct for flat/dark fields.
I use the 3.8 degree prism from Paton Hawksley.
All focusing was done with RSpec.
I have attached my results.
These differences are obvious. The prism definitely makes a difference.