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It's a Konus
Vista
model, but is exactly the same of Orion Short Tube and Celestron
FirstScope
80. I dissuade anyone to use it for deepsky imaging because the
corrected
field is very little, about 20 mm diameter: in the borders of 24x36
film
the stars are horrible. The cause is field curvature, so you must pay
attention
to focus in the center of the field, if you don't want a ring of
focused
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.
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