A finderscope is a key upgrade for any telescope. Often, even high-end telescopes come with subpar finderscope, straight out of the box. Cheap finderscopes can have narrow fields, poor adjustment controls, and in some cases, may even wobble and refuse to stay centered through the night.
Celestron has an answer for that, with their new RACI finderscope (Right Angle Correct Image). With a 9×50 (nine times magnification, 50mm aperture) setup, the RACI finderscope comes with a dovetail mounting bracket and a double-crosshair, illuminated reticle powered by three supplied three-volt watch batteries.
Focusing adjustments are simple with the RACI finderscope, and using the red-illuminated reticle is easy and intuitive. Like the Telrad, you can tune the brightness of the crosshairs as needed, and you can dim it enough so it won’t hide stars in the field of view. The crosshair reticle would also be handy for auto-guiding during astrophotography.
What I really like about the RACI finderscope is the true view of the sky that it offers, very similar to a good set of 7×50 binoculars with a bit more punch in the magnitude department, down to about 11th magnitude. The finderscope’s view isn’t inverted left-to-right or north-to-south, which is handy for comparing what you’re seeing at the eyepiece. In the field, I was able to star hop to the Ring Nebula (Messier 57) and the famous ‘double-double’ Epsilon Lyrae in a snap, simply by scanning the field of view with the RACI finderscope. As with binoculars, the major Galilean moons of Jupiter also stood out in the view during acquisition.
One possible drawback is the right-angle view: while comfortable for use (a plus), the RACI probably won’t be your only guider, unless you’re using plate-solving software (aligned with GPS) for pinpoint aiming. The finderscope would, however, work great in tandem with a 1x finderscope such as a Telrad or red dot-finderscope during initial acquisition. I could even see the utility of the RACI finderscope as a quick stand-alone daytime spotting ‘scope.
The Celestron RACI Finderscope is a worthy upgrade for any astronomy setup.