Nice lens. I have an SRT-102 and a X-370 with MD & MC Rokkor-X 50mm lenses.
I learned the hard way that the X-370 is no good for astrophotography. The -102 is what is classified as a ‘combat camera’.
Just about all those older film SLRs will need new mirror foam and light seals. The good news is a reputable repairman should not charge more than a few dollars for both. My repairman who just retired, only charged two bucks for replacing the light seals. I think the mirror foam should be about the same.
If you can find the materials you can do it yourself, It is not a difficult or technical job. Just remove the old seals and foam which probably will have turned into black goo, then place new material in the slots. The foam for the mirror to bounce on is also fairly easy. You can probably find the materials at an arts and craft section of a large discount store.
I still have my X370 I bought back in '85. I never had a problem getting shots of a full moon. I never tried to photograph anything else in the night sky though.