Guys, I've stuck this up top because I think it will be a good thing to have a set of "Equipment Basics" threads up top, especially for beginners. I'm certainly prepared to modify the idea if the users of the section don't like it.
Jim
I'm starting this thread to share the joys of reflex finders with those who have never used them, and to get feedback from observers using various types. I was about to flood a reply to Snazee1 with all of this, but decided to move it to it's own thread, as this is a subject we can expect to refer novice observers to in the future on this board.
For years, I've used a Telrad finder on many of my telescopes, and have found it to be a wonderful tool for visual astronomy. I've also used various other "reflex" finders. These are nonmagnifying, zero power displays which act like a modern aircraft "heads-up" display. You look at the real sky with both eyes open, but position your head so that one eye is behind the projection glass of the finder. What you will see in the case of the Telrad is three focused concentric red circles which appear to float against the sky.
The circles subtend angles of four degrees, two degrees, and one-half of a degree. Brightness is adjustable for varying conditions, and can be coaxed from an almost invisible glow to a level bright enough for use in twilight. Here is a link to an obviously enthusiastic Telrad user with a nice image:
www.monmouth.com/~govega/telrad.htm Also, here is a description of the development of the Telrad by the late Steve Kufeld, a southern California amateur astronomer:
www.company7.com/telrad/ The Telrad has become so popular that there are a slew of other reflex finders now available. The only real weakness of the original Telrad is the weight - about 11 ounces with batteries. On smaller Dobsonians with critical balance, this can require counterweights. The Rigel Quik Point is one of the better imitators - it is lighter than the Telrad (less than 1/4 the mass) but still retains a concentric circle reticle, which I feel is very helpful for observers just learning to starhop and estimate angular separations in the sky. The circles on the Quik Finder, however, are equivalent to just the inner two circles of the Telrad reticle - two degrees and 1/2 degree. This very slightly complicates using one of the popular Telrad "finder chart" books for Quik Finder users.
Here's a picture and description of the Quik Finder:
hardinoptical.com/quikfinder.html The other very common variation is a red dot finder like the Orion EZ Finder, the Televue Qwik Point, and the Celestron Star Pointer. These all seem to come from the same manufacturer, and show a red dot in a fairly tiny (less than 1/2" diameter) hooded projection lens. They have the advantages of light weight, low cost, and are bright enough for use in daylight, but don't give any sense of angular size.
The one exception to these comments in the realm of red dot finders is the very elegant, very pricey Televue Star Beam. The Star Beam's optics yield a precise 10 arc minute (about a third of a full moon) translucent red dot with variable brightness. Star Beam's large lens makes it very easy to find correct eye position, and it looks perfectly at home on an expensive refractor. Here's a link to Televue's description of both the Star Beam and the Qwik Finder:
www201.pair.com/resource/astro.html/regular/products/tele-vue-optics/qwik-point.htm I used a Qwik Point on my Televue Genesis Sdf refractor when I first purchased it, but it just looked too clunky on that gorgeous tube, and was a pain to use compared to my trusty Telrads. A Telrad would've been even worse aesthetically - that plastic box is a little clunky looking on a sleek refractor. So I swallowed hard and spent over $120.00 on the Star Beam, based on my faith in Al Nagler. Winner! The Star Beam is an absolute joy to use, although I still use my Telrads on other scopes. I feel the Telrad bullseye reticle is much more useful for beginners.
And, yes, I still also use conventional finder scopes, but I rough slew with a reflex finder first if I don't know the position well enough to get it in the field with the reflex.
It's pretty cool to get good with a Telrad. A friend will be having trouble finding an object, and asks if you know the starhop. You walk up, glance at the Telrad, move the scope, and then, if you're feeling cocky, not bother to look in the eyepiece and just say "OK - check the eyepiece now." When they look in the eyepiece and the object is there, just casually saunter off, looking like a wizard......
Anyway, having babbled on this long about reflex finders, I'd like to solicit comments and experiences in the use of these devices from fellow amateur astronomers.
Clear Skies!
Jim
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