Airmass a measure of the amount of air along the line of sight when observing a star or other celestial source from below Earth’s atmosphere

Constellation Imaginary pattern found among the stars, resembling animals, mythical heroes, and the like; different cultures map different constellations. Here are some constellations viewable from the northern hemisphere at different parts of the year.

Declination (abbreviated Dec)  Angular distance from the North-South of the celestial equator of the celestial sphere (measured in deg:arcmin:arcsec from 0 along the celestial equator to +90° at the north celestial pole and -90° at the south celestial pole)

Right Ascension (abbreviated R.A.)  Coordinates to measure east-west positions of the celestial sphere along the celestial equator (measured in hours:mins:sec from 0 to 24)

Light curve A plot of the brightness of a star (or any astronomical object) versus time.

Local Sidereal Time (abbreviated LST)  The local sidereal time (LST) at any given moment is the right ascension (RA) on the meridian at your observation position at that time. Objects having a RA equal to the LST are reaching their highest position in the sky during the day.

Magnitude  A measurement of an object’s brightness. The smaller the magnitude, the brighter the object.

For additional terms/information, visit Teach Astronomy