Tag Archives: church

A Close-Focusing Test with the Hastings-Byrne Refractor

by John Church In recent issues of Sidereal Times I’ve been discussing whether our 1879 Hastings objective was designed using John Herschel’s 1822 procedure.  Herschel’s method was a major advance that gave very good results for its time.  As part … Continue reading

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

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

Mars Opposition Photos from the Past

by John Church Left Picture: August 18, 1971         Right Picture: Oct. 11, 1973 Edmund 4-inch refractor            Hastings-Byrne 6¼ inch refractor Angular diameter 24.7 arcsec           Angular diameter 21.4 arcsec Central Meridian 10º              Central Meridian 328º                        Published in Sky & Telescope, March … Continue reading

Posted in November 2020, Sidereal Times | Tagged , | Leave a comment