Dear Fred, You wrote: "----There was also an article (with cover photo) in a 1975 issue of Sky and Telescope. I can't locate my copy at the moment, so I can't give you the specific issue. I subsequently had a letter to the editor printed in the Dec 1975 issue [50(6):355,382], pointing out how the dial related to Foster's work." ========================================================= The other 1975 SKY & TELESCOPE issue is October's [50(4):217-218], although there is not a cover photo, but an illustration at bottom left of page 218, accompanying Owen Gingerich's report on the Greenwich Tercentenerary Symposium.
Bill Maddux
