On Wednesday, 8 August 2018 13:28:40 UTC-4, wrote:
Le dimanche 31 octobre 1999 02:00:00 UTC-5, Christian Schims a écritÂ*:
I have bought a funny little scope on a flea market, that seems to be
very rare here in Germany. Its a Bausch & Lomb Criterion 4000 (4" SCT)
including a rifle-type finder scope and a 24mm kellner(?) eyepiece.

I even did not star-test ist. So, can anybody tell me anything about
this instrument, e.g. f-ratio, expectable quality, approx. manufacturing
time etc.

Thank in advance
Chris

I had the 8000. it was from 1981. this one is from the same line.No correcter in the entry "glass". just a glass. but its still a great scope for its size. I just got one 4000 for 150$. i'll use it as a spotting scope with 32 mmm on my c8.

What do you mean, "no corrector?" All Schmidt-Cassegrains have corrector lenses in the front. The curve is so shallow, the glass appears flat.