from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The middle to highest point of a part of an ecliptic that is above the horizon at any period of time.
from the GNU version of the Collaborative International Dictionary of English
- adj. Of or pertaining to the ninetieth degree or to a nonagesimal.
- n. The middle or highest point of the part of the ecliptic which is at any given moment above the horizon. It is the ninetieth degree of the ecliptic, reckoned from the points in which it is intersected by the horizon.
from The Century Dictionary and Cyclopedia
- Belonging to the number 90; pertaining to a nonagesimal.
- n. In astronomy, one (generally the upper) of the two points on the ecliptic which are 90 degrees from the intersections of that circle by the horizon.
Sorry, no etymologies found.
His commentary on Aratus shows that he had expounded, and given a geometrical demonstration of, the methods necessary to find out the right and oblique ascensions of the points of the ecliptic and of the stars, the east point and the culminating point of the ecliptic, and the angle of the east, which is now called the nonagesimal degree.
“Jupiter nearest the nonagesimal had passed by four degrees the trine of Saturn; the Sun and Venus in conjunction were moving from the latter towards the former, nearly in sextiles with both: they were also removing from quadratures with Mars, to which Mercury was closely approaching: the moon drew near to the trine of the same planet, close to the Bull's Eye even in latitude.
If we place the standard of gravity in latitude 45° of the nonagesimal division, we shall have y '= G. (1 — .00275 cos2a — .0000000957/0 -