JSP EasyTester 133 LPI Ronchi Grating Tester
From Jack Schmidling Productions, the EasyTester is an eyepiece-like
device that allows the owner or user of any type of telescope to quickly
determine the quality of the telescope optical train with no previous
experience or skills.
The EasyTester consists of a classical Ronchi grating mounted in a
standard 1-1/4" eyepiece tube. When the device is focused on a bright
star, a pattern of parallel lines appears that can be used to determine
the optical quality of the system and identify many of the common faults
that plague commercial telescopes. If the lines are straight and parallel
to the edge, one can conclude that the mirror or objective lens and the
secondary and corrector plate are well figured. If the lines appear to be
anything other than straight and parallel, a comparison to the supplied
defect chart will quickly identify the type of error involved. With defect
reference chart, allen wrench for focus range adjustment and bolt style
case. Lifetime warranty.
Prices include shipping in the USA!