ATM TERMINOLOGY - P
- Parafocal:
- A set of eyepieces is said to be parafocal if you don't have have to readjust the position of the focuser when changing eyepieces.
- Polishing:
- The polishing process is done after fine grinding and is intended to remove all grooves and pits made during grinding. The resulting shape should be (near to) spherical. (The next process is figuring)
- Prime focus:
- The focal point of the main mirror (at least for Newtonians).