University Lowbrow Astronomers

New ‘Scope’ Review.

by Christopher Sarnecki
Printed in Reflections: December, 2002.

Our Newsletter Editor is always on the look out for the next newsletter article for the Lowbrows Reflections.  He has reminded me numerous times of the need to write an article about the new telescope I been using for the past year.  Well, Mark; wait no longer.  This new telescope review is for you.

About two years ago, I decided to retire the 13-Inch Coulter newtonian reflector with its companion Telrad and finder scope.  My old Mark Cray built f/5, 85-mm doublet finder was an awesome finder.  It had a 90-degree star diagonal that produced an image that was up side down and reversed left to right.  I would tell myself that I could figure out where I was in space; but most of the time, I was “lost in space” and I would just fish around and sweep up the desired object.  The Coulter, Telrad, and Cray finder served me well for more years than I care to remember, but it was time to try something different.  Along with a new scope and reflex finder (Rigel), I decided I would also try a different finder scope.

I purchased an 8 x 52-mm right-angle, correct image finder by Sky Instruments of Vancouver, BC.  The finder is mounted on the traditional mounting rings with a quick release knife blade mount that makes set-up and tear down a snap.  This arrangement cost me about $150.  Orion Telescope & Binocular has a similar right-angle correct image finder that comes with an even simpler dove tail mount for about 90 bucks.  The Sky Instrument finder comes with a focusable eyepiece built in to the scope and is great for focusing the field of view to the individual needs of you eyesight.  Both finders are good products for a fair price.

What is so important about using a right-angle finder?  Traditional finders provide the view by looking straight through the scope like looking through the little collapsible spyglass you had as a kid.  The straight through finder also produces an up side down view of the universe.  Try using one of these finders on any style scope, whether it be a newt, Cassegrain, or refractor, and one finds that in some orientations, like at zenith, the straight through view is difficult to impossible to use.  The right-angle feature eliminates contorting your neck to use the finder at any scope orientation.

How do these right-angle correct image finders provide the corrected views you ask?  Smoke and mirrors, well maybe only mirrors.  Actually an amici prism provides the corrected view that matches the view of the universe you see when you look up in the sky with your own eyes.  This is much more intuitive when comparing the sky against your star atlas.  I usually use the Rigel to locate a bright star near to object I am looking for, then compare a path on the atlas to what I see in the finder scope.  If I need to go left on the chart, I just look in the little scope and go left.  No need to try and flip views in your mind top to bottom or left to right.  WYSIWYG astronomy at its best.  How well do the right-angle correct image finders perform?  After a season of use, I can testify that these little scopes are the best thing that has happened to observational astronomy since John Dobson.  If the night’s seeing will permit it, the telescope is up to the task, and given a decent atlas, I can find anything!  The 50-mm finders locate stars to about 10th mag on most nights.

Planetary observing has never been my forte.  Many of these objects are small and hard to find.  If one can’t find the spot where a smallish planetary is on the celestial dome, it is useless to apply the magnification.  With the right-angle correct image finder locating these little gems is an enjoyable experience.  I know exactly were I am at most of the time by just using the view in the finder.

A couple of no cost tricks I use to keep the dew of the finder’s eyepiece and objective are worth mentioning.  I connected the eyepiece plastic lens cap to a piece of elastic thread and then to the finder.  If dew is expected, I cover the eyepiece with the cap when not in use.  I never have to go looking for the cap because it is always attached to the finder.  To keep dew from forming on the objective I made a simple insulated dew cap from the black foam plastic stored in the observatory.  Dew has never been a problem on the finder’s objective since I installed the foam dew shield.

If you enjoy finding objects from a star chart and don’t like to strain your neck, try one of these little scopes.  It will open up more of the universe and provide the next level of observing challenges you may find you need to keep you looking forward to the next night out under the stars.

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Copyright © 2013, the University Lowbrow Astronomers. (The University Lowbrow Astronomers are an amateur astronomy club based in Ann Arbor, Michigan).
This page originally appeared in Reflections of the University Lowbrow Astronomers (the club newsletter).
This page revised Sunday, March 9, 2014 4:30 PM.
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