finderscope
Telescope's targeting accessory
A finderscope is a small, low-power telescope mounted on a larger telescope to help locate celestial objects.
Because high-powered telescopes have narrow fields of view, the finderscope's wider view makes it easier to aim at a target before switching to higher magnification: I spotted Jupiter in the finderscope, then centered it in the main eyepiece.
Optical sighting pattern
- crosshairsIntersecting sighting lines
- calibrationAdjusting for measurement accuracy
- collimationMaking light rays parallel
- zeroingCalibrating to baseline
adjustment · mounting · bracket · fine-tuning · securing · aiming · centering · setup
Overhead darkness after dusk
- constellationsRecognized celestial groupings
- celestialOf the sky above
- backyardOutdoor space behind home
- cometIcy orbiting body
meteor · starlight · planets · galaxy · nebula · deep-sky · skywatching · locating
Lens you look through
- lensLight-focusing curved glass
- magnificationDegree of visual enlargement
- apertureAdjustable optical inlet
- focusConcentrated attention point
refractor · achromatic · diopter · glass · image · brightness · clarity · objective
reticle
Optical sighting pattern
- crosshairsIntersecting sighting lines
- calibrationAdjusting for measurement accuracy
- collimationMaking light rays parallel
zeroing · adjustment · mounting · bracket · fine-tuning · securing · aiming · centering · setup · orientation
night-sky
Overhead darkness after dusk
- constellationsRecognized celestial groupings
- celestialOf the sky above
- backyardOutdoor space behind home
comet · meteor · starlight · planets · galaxy · nebula · deep-sky · skywatching · locating · tracking
eyepiece
Lens you look through
- lensLight-focusing curved glass
- magnificationDegree of visual enlargement
- apertureAdjustable optical inlet
focus · refractor · achromatic · diopter · glass · image · brightness · clarity · objective