Antoniadi scale
parallax
optical astronomy
telescopy
eyehole
scopeful
metrology
skytime
reflectometry
reflector
observatorial
astronomics
umbraculate
telescopic
femtoscale
subvisually
semiempirical
areographer
opticianry
ultrasonographics
sight
visual sense
visual modality
Y level
ocularity
observatory
solar telescope
vision
monocular
radio observation
telescopically
visuoconstructive
observing
stargazing
Systeme International d'Unites
perspective glass
SI
eye test
Systeme International
SI system
astrointerferometer
International System
visuoconstructional
International System of Units
SI unit
field glasses
metrics
peepshow
-scopy
watch