Product Description
This item is very unusual. It is a Davidson Optronics Model 104-0145 90-degree Prism Adapter. The adapter fits onto the ends of the standard 58mm diameter collimator objectives tubes. There are two ports on the side of the ‘cap’, and the collimator beam is split so one half is directed at 90 degrees to the right, the other half 90 degrees to the left. The reflector is a solid prism with silvered surfaces – I am not sure if it is polished metal or silvered glass. The adapter has a knurled cover that may be turned to block the side apertures.
I have not been able to discover any specifications on this device (such as the angular deviation of the right and left optic axes) but considering the manufacturer is Davidson Optronics, I would infer it is a very high precision device. I am not sure of its original application, but imagine it would be very useful for aligning two opposing mirrors parallel to each other without having to juggle any fixtures. For the last photo I placed different colored cards on either side of the mirror. The prism peak is actually quite sharp, but there is some cutoff in the reflections that makes it appear truncated.
Condition of the adapter is near perfect – the prism surfaces appear to be completely free of blemishes. The adapter did not come with any protective cabinet.
Location MB 53-5
Photo set 539