To see objects through a telescope it must be pointed to exactly the right spot. The Telrad is a sight for pointing telescopes to that "right spot." Through a Telrad you see the sky the way the star charts show it. Not a small upside-down and magnified portion of it, but the "real sky" with three lighted target rings set against it. The large ring is 4 degrees across. It outlines the area covered by a finder scope. The center ring is 2 degrees in diameter. The small ring is 0.5 degrees across and outlines the area seen in the telescope.
Select an object on the chart and note its position among the visible stars. Then set the Telrad rings on that spot in the sky. A quick rough setting will put the object in the field of a finder scope. With no finder, or a faint object that won't show, use a more careful setting to put the object in the field of the telescope.
The reticle pattern in this model is illuminated by a red LED. A separate version of the Telrad is available in which the user can select between red or green illumination.
The Telrad is 8.15" long and 2.24" wide (at the base) so please make sure that you have sufficient clear area on your telescope tube to mount this as this could be a challenge on very short OTAs. The Telrad weighs a mere 11 ounces due to its lightweight yet robust ABS plastic construction, and mounts without drilling holes using the double-sided tape on the bottom of the Telrad base. It unlocks from its base for separate storage. This version runs on two AA batteries (not included).
The Telrad Sight has also found wide adoption in the stage lighting industry. It works very well as a follow spotlight sighting device for professional concert and stage spot light operators. However, a new Telrad version with brighter, white illumination is now available for those applications.
- Magnification: 1x (Zero power)
- Weight (with 2 AA batteries, not included): 10.1 oz.
- Total length: 8.15" / 207mm
- Total height (with base): 4.92" / 125mm
- Maximum width (excluding base screws but with base on): 2.24" / 57mm
- Maximum width (without base): 1.81" / 46mm
- Viewing window dimensions (full lengh, not vertical height): 2.52" x 1.42" (64mm x 36mm)
- Base thumbscrew specification: 6-32, 0.5" long (2x)