Tag Archives: church

News Flash!!

Posted on May 3, 2014 by ST Editors

by John A. Church Here is a news flash, hot off the wires! On Saturday April 26, Rex Parker, Jeff Bernardis, Dave Skitt and the writer successfully replaced the existing Paramount mount on the Hasting-Byrne refractor at Washington Crossing with … Continue reading →

Posted in May 2014, Sidereal Times | Tagged , , | Leave a comment

Daystar

Posted on September 3, 2013 by ST Editors

by John A. Church Whenever I have trouble getting to sleep, which sometimes happens to people as they get older, I just think about the sun. I first learned interesting things about the sun from The Beginner’s Star-Book. a delightful … Continue reading →

Posted in September 2013, Sidereal Times | Tagged , | Leave a comment

The Observatory Has Been Painted

Posted on October 3, 2012 by ST Editors

by John Church After a complete power washing and also spot bleaching where needed, our Simpson Observatory at Washington Crossing State Park is sporting a brand new double coat of white latex semi-gloss on the exterior of the cinder blocks … Continue reading →

Posted in October 2012, Sidereal Times | Tagged , , | Leave a comment

Geometrical Optics and the Hastings-Byrne Refractor: Part III

Posted on June 4, 2012 by ST Editors

by John Church In the March and April issues I reviewed the relatively simple equations that allow a lens designer to specify the total curvatures of both elements of a two-element (crown and flint) achromatic refractor objective, and how our … Continue reading →

Posted in June 2012, Sidereal Times | Tagged , , | Leave a comment

Geometrical Optics and the Hastings-Byrne Refractor: Part II

Posted on April 1, 2012 by ST Editors

John Church Last month I reviewed the “lens-maker’s formula” that allows one to calculate the focal length (the inverse of the “power”) of a thin lens, provided that one knows the refractive index of the glass and the radii of … Continue reading →

Posted in April 2012 | Tagged , , , , | 1 Comment

Geometrical Optics and the Hastings-Byrne Refractor

Posted on March 6, 2012 by ST Editors

By John Church Some years ago I analyzed the objective lens of the AAAP’s historic 6-1/4-inch Hastings-Byrne (H-B) refractor and published the results in Sky & Telescope magazine, along with a history of the telescope1. The readers of Sidereal Times … Continue reading →

Posted in March 2012, Sidereal Times | Tagged , , , | Leave a comment