Dictionary of Physics or an Attempt at an Explanation of the Most Important Concepts and Technical Terms of Natural Philosophy

the degrees of the same be converted into time, see the articles: Sidereal Time, Solar Time. Thus, 270° in the assumed example give 18 sidereal hours or 17 h 57 min 3 sec mean solar time. This much time therefore elapses, calculated from noon, before the vernal equinox reaches the meridian.

In the best astronomical calendars (e.g., Bode's Astronomical Yearbook), one finds this distance in sidereal time for every noon of the year, under the heading: Eastern distance 0°♈ from the sun. It is used to find the hour at which every star crosses the meridian, see Culmination.

Descending Nodes, see Nodes.

Descending Signs, see Zodiac.

Descent, Right, Descensio recta, Descension droite is completely identical to right ascension. It is understood to be the arc of the equator contained between the vernal equinox and the circle of declination of a star. The last point of this arc rises and sets simultaneously with the star in countries where stars rise and set at right angles; it therefore bounds its right ascension and descent at the same time, which is why both are identical. See Ascension.

Descent, Oblique, Descensio obliqua, Descension oblique. That arc of the equator which is contained between the vernal equinox or beginning of the equator and the point of the same that sets simultaneously with a star. For comparison, see the article: Ascension, Oblique.

The difference between the right and oblique descent of a star is called its Descensional Difference. For stars that do not change their position significantly relative to the fixed stars, this is identical to the ascensional difference, see Ascensional Difference. From it, the oblique descent is found through the formula