DIY adapter for vintage right angle finder
First tried duck tape but it wasn't stable.
So I sawed a section of thick PVC tube which inside is a bit larger than 1", then
drilled 2 x 2 holes along, each pair separated by 120° approximately, and
finally threaded them.
Now one side is assembled to the angle finder, and I can assemble the other
* my polar finder for my EQ mount
* my 2 scope finders, 6x30 for the MAK and 9x50 for 130PDS.
PS: the angle finder is from Asahi Pentax and has proven of very good
optical quality; The effective FoV is about the same as the original finder I
assemble it on.