Dear Mr. Nagler,

In 2011 I finally bought a Tele Vue NP101is APO refractor which has a perfect focal length for wide-field imaging, suitable for many objects. The color correction of this nice piece of equipment turned out to be superb and even the green and red filtered images tend to be sharper than what I was used to have with (another refractor brand) and these are already very sharp. The relatively fast optical speed (f5.4) helps to get a lot of light within a short time. The new "is" series also has an improved focuser that allows more light to reach the detector, especially if it is full format or even larger. The bottom line here is that there is less an issue with vignetting than compared to the non-"is" series. Another aspect of the Tele Vue NP refractors is the possibility to upgrade with a completely motorized, high-precision focusing system. It specifically fits to these telescopes and has some unique features not found elsewhere. Although I am not using this motorized focuser at the moment, this is certainly an option I consider for a future upgrade.

Fabian Neyer
Switzerland