426 EXPLANATION OF THE PRINCIPAL TERMS

Longitude of a star or planet, is its distance from thefirst point of Aries, reckoned in degrees, minutes, &c.upon the ecliptic.

Lucida Lyra, a fixed star of the first magnitude in theconstellation Lyra.

Lucifer, the morning star, Venus, so called when sheis in the east, and rises before the fun.

Luminaries, the fun and moon, so called by way ofeminence, on account of their extraordinary liistre,and the great light they afford us.

Lunar Aspects, are those which the moon makes withany of the other planets; as when she comes in opposi-tion, trine, quartile, &c.

Lunation, a lunar fynodical month, or the space of timebetween one new moon and another, which is gene-rally about 29 days, 12 hours, 44 minutes, and 3 se-conds, being greater than the periodical month by twodays and five hours.

Luni-Solar Year, a period made by multiplying thecycle of the moon 19 by that of the fun 28.

Lupus, the Wolf, a southern constellation consisting ofthirty-six stars.

Lyra, a constellation of the northern hemisphere, con Tfisting of twenty-four stars.

M.

Maculæ, dark spots, appearing on the face of the fun,moon, and some of the planets, being contra distin-guished from Faculæ, which are bright or shiningspots, that, by means of the Telescope, are sometimesto be seen on the face of the sun, &c.

Magnitudes ; the stars are divided into six sizes, orclasses; of which the brightest are called stars of the first

magnitude ;