This sample I selected on an exhibition as the best and I have seen until today only worse samples. I heard bad things about the optics, but this one really has good optics. They are smooth and i would say the wavefront p.t.v. is about 1/5. The startest show an tine zone, which can also be seen in the ronchimages. For the money this telescope goes it is an excellent value . The high power infocuse image show only 2 diffraction rings and clean bright airydisc, it have an good contrast “
Markus Ludes (APM-telescopes)
Note: ronchi-testing with 254 lines/inch or 100 lines/cm.