In article , Paul Mitchum wrote:
Paul Murray wrote:

My father-in-law has come to stay, and dropped off an interesting present he
thought he had lost years ago, but has just found again.
It is an eyepiece adapter than connects directly to a Pentax-fit lens, and
allows you to use it as a telescope. He say he thinks it has an effective
10x magnification, so that a 200mm lens becomes a 2000mm telescope.
It is certainly useful for birdspotting around the garden.
Written around the adapter is
"BOB PATP 54038748 APK TELEPHOTO LENS ADAPTER JAPAN"
Does anyone know anything more about this piece of equipment?
Pentax made this monocular converter:
http://www.bdimitrov.de/kmp/lenses/adapters/monocular.jpg Does it look
familiar?

No, I think it is a third-party adapter rather than a Pentax one.
It is much shorter between lens mount and eyepiece.
One thing is have found is that it can't use anywhere near the full amount
of glass on the front of the lens, so it doesn't have great light-gathering
performance.