Tag Archives: church

John Herschel and his Lens Designs

by John Church Charles Hastings once wrote that the lens which is now on our Hastings-Byrne refractor was similar in design to the types described by John Herschel (1792-1871). He also mentioned that such lenses do not greatly differ from … Continue reading

Posted in April 2021, Sidereal Times | Tagged , , | Leave a comment

How Did Hastings Design Our Objective? Part Two

by John Church Objectives for smaller telescopes are sometimes designed to conform to the “Herschel condition” proposed by John Herschel in two papers in the early 1820’s.  These objectives perform well at nearby distances as well as on celestial objects … Continue reading

Posted in March 2021, Sidereal Times | Tagged , | Leave a comment

How Did Hastings Design Our Objective?

by John Church PART I I’ve often wondered what actual methods Charles Hastings used when designing the 6-1/4” objective now sitting at the business end of our fine refractor in Washington Crossing State Park.  I’ll start by quoting Hastings’ own … Continue reading

Posted in February 2021, Sidereal Times | Tagged , , | Leave a comment

From the Program Director

by Victor Davis The first AAAP meeting of 2021 will take place (virtually) on Tuesday, January 12th at 7:30 PM. (See Joining the Meeting with Zoom below for details). This meeting is open to AAAP members and the general public. … Continue reading

Posted in January 2021, Sidereal Times | Tagged , , | Leave a comment

Some Notable Conjunctions of Jupiter and Saturn

by John Church As we are all aware, there will be a close conjunction of Jupiter and Saturn in the evening sky of Monday Dec. 21, which coincidentally is the same day as the winter solstice.  Jupiter passes Saturn once … Continue reading

Posted in Great conjunction, Sidereal Times | Tagged | Leave a comment