Position Angle Scales for Telescopes

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Dec 24

2015

by project nightflight

Got a telescope for Christmas? Here's a gadget you can easily make yourself that greatly improves the usefulness of your new instrument: A position angle scale that shows you the celestial directions in your eyepiece.

When viewing the heavens through the eyepiece of a telescope, one can get lost easily. Where the heck is southeast in the field of view? Does Jupiter rotate from left to right or from right to left? Which way does the tail of that comet point? And where can the elusive companion of this double star be expected? These are some of the questions that arise during many observing sessions, night after night.

As an easy solution we provide a position angle scale that can be printed on cardboard and placed between any 1.25-inch eyepiece and focuser. Once oriented, it points out the celestial directions in the field of view, shows the position angle and even tells the rotational directions of planets. There are two scales available, one for direct views (e.g. through Newtonians) and one for mirror-reversed views (e.g. through refractors with star diagonals). The scales come complete with instructions and can be downloaded for free from the project nightflight website: http://project-nightflight.net/position_angle.pdf