reflecting telescope

noun 0.875

refractor

noun 0.750

telescope

noun 0.741

refractometer

noun 0.690

radio telescope

noun 0.669

solar telescope

noun 0.661

riflescope

noun 0.659

refraction

noun 0.618

refractometry

noun 0.591

parabolic reflector

noun 0.580

interferometer

noun 0.572

retroreflector

noun 0.565

refractive power

noun 0.560

reflector

noun 0.558

dioptric

noun 0.556

refractive index

noun 0.555

optical astronomy

noun 0.555

telephoto

noun 0.554

reflection nebula

noun 0.552

compound microscope

noun 0.551

retinoscope

noun 0.548

optical microscope

noun 0.546

refractivity

noun 0.543

gravitational lens

noun 0.539

parabolic mirror

noun 0.538

microscope

noun 0.529

spectroscope

noun 0.528

diffraction grating

noun 0.527

telescoping

noun 0.525

theodolite

noun 0.520

simple microscope

noun 0.515

resectoscope

noun 0.514

convex lens

noun 0.512

observatory

noun 0.511

reflecting

noun 0.510

camera obscura

noun 0.504

radar reflector

noun 0.504

optical glass

noun 0.504

ophthalmoscope

noun 0.503

spyglass

noun 0.502