Monthly Archives: July 2020

IntroductionHere is a set of formulae and numbers that I have always wished was in one place.  Now they are.  Enjoy.f ratio (or focal ratio) = primary mirror focal length…

There are three types of telescopes for the Amateur Astronomer, refractor, reflector and catadioptric. All these designs have the same purpose, to collect light and bring it to a point…

The following is a basic guide to some of the factors to take into consideration when choosing eyepieces. It is based on my experience but also on conversations with and…

Hi all,Just thought I would write up the instructions for making a very sensitive jam jar magnetometer. The plans are based on instructions found on the internet, but it was…

My heart leaps up when I beholdA Rainbow in the sky:-- The Rainbow by William Wordsworth Painters, poets, and photographers have long tried to convey to us through pictures and…

In the first installment of this series on atmospheric optics we touched on various aspects of rainbows that one can witness. Now, let us turn our attention to those strange…

The Ursids meteor activity begins annually around 17th December and runs for for just over a week, until the 25th or 26th, with a peak on 22nd December. This meteor…

Armagh Observatory, 5th May 2006: A comet, currently breaking apart, is visible in our eastern evening sky in the constellation of Lyra. Comet Schwassmann-Wachmann 3 (SW3) has broken into at…

The GeminidsThe Geminid meteor shower officially begins on December 7th, but it doesn't peak until the morning of the 13/14th. Unlike the Leonids, the Geminid's broad maximum lasts nearly a…

The Lyrid meteor shower streams from a point in the constellation Lyra near Vega - a brilliant blue-white star about three times wider than our Sun and 25 light years away. The…