Chuck,
The scope I put together for SLAS's H-Alpha DayStar filter is a 50 MM f 30, works good. Vaughan Parsons made a 80mm f 30 for his Daystar filter works very well, all singlets. The filter works well on anything longer than f 30, you should try it out on your singlet lens. Erik Observing report with the F/40 singlet configuration: Lunar craters along
the terminator clearly discerned as such. Any detail on the face of the moon, however, was too awash with color to clearly see. Jupiter was a colored disk, tint depending on just where the eyepeice was racked in relation to the part of the spectrum in focus at that particular point. No Jovian moons seen in a bright dusky sky.
I may try later if I don't fall asleep first.
Right now I feel very grateful for modern optics, and a renewed appreciation for astonomical pioneers who made some incredible discoveries with stinko telescopes. _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com