(updated 15 may 2002 - currently listing :  38  telescopes)

The newest additions and changes can be found on the NEWS page

This website is a joint effort of Markus Ludes from APM-Telescopes and Cor Berrevoets (Aberrator free startesting Software). The site aims at explaining the different aspects of star-testing telescopes. For this many diffraction images of inside and outside focus artificial stars are available for different telescopes. Accompanying these images are texts explaining what can be seen in the images. Images with a * on the list are also tested with a new software tool under development (see PSF-extraction)

These startesting images have been made in the following manner:

Markus Ludes (APM telescopes) used a high quality 10" Maksutov Newtonian (Zygo tested at 632,8 nm with the following errors: 1/10.1 wavefront p.t.v. and 1/51 wavefront RMS) as collimator in single pass scheme. This represents images alike a real startest under real skies but without seeing affecting them. The images were taken in the APM Testing room. Although the 10 MN has a large unobstructed area some telescope (>125mm aperture) will show additional vignetting due to the secondary obstruction.

Note: the images dated later than 2 june 2001 are taken using a 9" F/9 Triplet Super ED TMB Apo (with very high strehl ratio) as a collimator.

A Canon EOS D30 Digital camera was used using eyepieceprojection. The eyepieces used were Zeiss Abbe Orthos (ED) The exposure time for large images was around 15 seconds and for smaller images 8 seconds.