I never ever thought I'd find one of these, but I came accross one while casually browsing eBay.
This Pentax Monocular Converter turns any K-mount lens into a telescope, multiplying its effective focal length by a factor of 5. In other words, my 400-600mm mirror lens turns into a 2000-3000mm telescope! Plus, the view through the converter is much clearer than that through the eyepiece of a standard telescope
I guess it'll be fun to bring long on long trips
