GRADED A+
◉parsec . Answer: distance of an object whose parallax is 1 arcsec
◉apparent magnitude of a star . Answer: logarithm of the flux received
from the star
◉declination . Answer: angular distance to the celestial equator
◉right ascension . Answer: angular distance from the vernal point
measured along the equator
◉circumpolar . Answer: never rises and never sets, its declination is
high
◉ecliptic . Answer: Sun's trajectory on the sky during one year
◉millimeter waves . Answer: radiation between radio waves and
infrared waves in the electromagnetic spectrum