Bushnell Spacemaster = Big Eyes?

[duckhunter175]

Dad passed down his Bushnell Spacemaster this Christmas! It is a 25x eyepiece and 60mm OBJ. The model # appears to be 78-1800.

 

Initial google search seems to show that guys used these with a 15-45x eyepiece or they mounted two with fixed magnification together to make some big eyes.

 

Having issues finding other eyepieces or even another spotter with the dual mount. Any ideas besides eBay?

 

Thanks!