It's a Konus
model, but is exactly the same of Orion Short Tube and Celestron
80. I dissuade anyone to use it for deepsky imaging because the
field is very little, about 20 mm diameter: in the borders of 24x36
the stars are horrible. The cause is field curvature, so you must pay
to focus in the center of the field, if you don't want a ring of
stars with in the middle defocussed stars...
For the low-power visual observation is almost good, only some cromatic aberration, big but not too much for a f/5 refractor. An artificial star test showed the non existence of a focus point because of cromatic aberration, and a very big astigmatism.