Does anyone know what each of the three sets screws do ? I have one large and two smaller screws on each side.
Hi.
The tri member screw groups in the front retaining ring are NOT collimating screws. They ensure the proper positioning of the two objective elements in their proper mutual arrangement. Notice that normally, they are positioned above the delicate foil spacers of the lens. In the specific objective, this in not the case. So someone in the past has touched the lens. I advise you the star test the lens, before any cleaning effort. Check for original orientation marks in the perimeter of the elements. If you can find them, use them into the reassembly process. If you cant spot markings, check carefully the inner perimeter of the lenses for any glue residue. If you cant spot any you can assume that the elements retain their original orientation, so make yours with pencil and pray for the best. The lens performance optimization with the relative rotation of the elements is a very delicate and time consuming process.
After cleaning, the front retaining ring must return in the normal position with the screw groups above the foil spacers. In order to adjust screw pressure, try to find description of the Newton rings method elsewhere in this forum. A very useful discussion can be found at: https://www.cloudyni...on-rings/page-2and specifically at: https://www.cloudyni...ings/?p=6285071
Regards
Dimitris
Edited by mitsos68, 19 January 2022 - 03:28 AM.