The Telrad is the best-selling non-magnifying finder for Dobsonians, equatorial reflectors, refractors, and Schmidt-Cassegrains alike.
The Telrad projects a bull's-eye pattern of concentric red rings (4 degrees, 2 degrees, and one-half degree in diameter) on a tilted clear viewing plate at the top of the finder. These circles, which seem to be projected on the sky itself, make it easy to starhop from object to object. If a galaxy is 10 degrees north of a known star, for example, two 4 degree Telrad jumps and one 2 degree jump from the known star will take you to that galaxy in seconds. The half-degree circle makes it easy to quickly center a computerized scope on guide stars for start-up alignment, and to center on planets, comets, and deep space objects if you’re scanning the sky manually. The red circles can be seen from virtually any distance behind the Telrad, from two inches to two feet, so eyeglass-wearers can easily use the finder.
The Telrad is normally used as a straight-through finder, similar to the heads-up display in a military aircraft cockpit. Its base attaches quickly to any optical tube 6” and larger in diameter by means of double-faced tape (or by screws into a Sonotube reflector optical tube, through two screw holes in the mounting plate). The finder itself fits into a dovetail slot in the base and locks in place with two finger-tighten side screws. The Telrad comes with one base standard, but additional bases are available so you can put a base on each scope you own and use one Telrad on several scopes.
An optional Dew Shield retards the formation of dew on the optics of the Telrad during long observing sessions. Additionally, an optional Dew Shield Plus combines a dew shield with a pivoting light-weight first surface flip mirror that allows the Telrad to be used as a straight-through finder, a right angle finder for observing at the zenith, and at any angle in between.
Collimating knobs at the back of the Telrad allow you to line up the finder with your main scope optics. An on/off switch and integral rotary brightness control allow you to match the finder brightness to your eye’s dark adaptation. An optional Pulsar pulsing reticle module is available to provide variable brightness and a variable on/off light cycle that many observers find more comfortable to use when hunting very faint objects. The Telrad uses two 1.5V AA batteries (supplied by Astronomics as part of our Telrad package).
The Telrad is 8” long by 1.75” wide by a maximum height of 5”, so it is difficult to use on the short and small diameter optical tubes of small scopes such as the Meade 3.5” ETX-90. If a non-magnifying finder is needed for such scopes, consider the #3960 Rigel Quikfinder instead.