Dear Mr. Baader,
I am happy to comply with your request and share with you my criteria that led to the purchase of the 17 inch telescope from Planewave, and following my experience with this telescope. Since this was a rather complex topic, please forgive the long text and its extent , which certainly clearly exceeds a "normal" customer judgment.
Decision criterions for the choice of the Planewave astrograph were primarily:
- robust mechanical construction of the whole telescope,
- fixed installation and collimation of primary mirror and field corrector at factory,
- stable secondary mirrorcell,
- easy adjustment of the secondary mirror,
- easy control of distance between the main and secondary mirror withRonchi test,
- good focus stability with slight temperature differences,
- affordable focal reducer available,
- a price difference of about 10.000 Euro to a RC telescope from renowned European or international
To the last point, my following remark: I have not looked into the RC telecopes offered on the amateur market, which are delivered at 16 inches opening and a price below 10,000 euros. Production at this selling price - especially for an RC system - was unimaginable to me. In addition, it is hard to find any reference images taken with these instruments on the Internet, in comparison European - made RCs and PlaneWave telescopes have many international references.
Does that Setup have any disadvantages? Little after almost 4 years of operation:
- the 17" Planewave has an open tube in comparsion to the 12.5 inch and the black "Spantex" cloth against scattering light is often "willing" and shifts easily above the main mirror that is quickly partially obstructed.
- main disadvantage is in my eyes the very short focus travel of the 3.5" electrical Hendrick focuser of just 32mm, but otherwise it works very decently.