Hint: If you look for a page about how to use a spherical mirror, got to ChristmasBallPanoTutor. This one is about mirror pages of the original panotools distribution.
Before Helmut Dersch closed his site with the original Panorama tools distribution some users managed to save his pages and mirror them in different locations. These mirrors where long time the main source of the complete panorama tools package and contain lots of information. Some core applications are only found there.
Unfortunately all the known mirrors went offline by now. Many thanks to Kathy Wheeler who gathered the pieces from different sources and made them work again. We have now one central working mirror (including the 15mm Heliar, the Frozen Moments and the Star Trails pages):
If you find any errors please report to Erik Krause