Obliquity Of The Ecliptic At Epoch 2000

23.4392911 Deg

RATE OF CHANGE OF THE 08LIQUITY (T IN JULIAN CENTURIES)

(-1.30125 x 10_2T -1.84 x 10~®T2 •»5.0 x 10_7T3I Deg

AMPLITUDE OF EARTH'S NUTATION

2.6588 x 10-3 Deg

LENGTH OF SIDEREAL DAY, EPOCH 19808

86.164.0918ns: - 23 hr 56 mill 4.0918 aac

LENGTH OF SIDEREAL YEAR, EPOCH 19808

3.1588149548 x 107 sec = 365.26636051 DaytD

LENGTH OF TROPICAL YEAR IREF °T| EPOCH 1880®

3.156925551 x 107 tec = 385-24219388 DaylH

LENGTH OF ANOMALISTIC YEAR (PERIHELION TO

3.1558433222 x 107 tec

PERIHELION). EPOCH 18809

- 365 .25964377 Day»"

'based ON THE ADOPTED VALUES OF < AND a.

* ASSUMING G - 6.672 X 10-11 m3 kg-1 ■~2: THE VALUE OF GM£ IS MORE ACCURATELY KNOWN. 8SEE APPENDIX J FOR FORMULAE AND DISCUSSION. " ONE DAY a 88.400 SI SECONDS.

Table L-6 summarizes the properties of the upper atmosphere of the Earth. The mean profiles between 25 and 500 km are from the COSPAR International Reference Atmosphere, C1RA 72 [1972]. Between 500 and 1000 km, the C1RA 72 profile for 7'00= 1000K was used to indicate the densities to be expected. The maximum and minimum values of the density between 100 and 500 km were extracted from the explanatory material in CIRA 72 and indicate the variation in densities which can be obtained with the models. Sea level temperature and density are from the U.S. Standard Atmosphere [1976].

Geocentric and Geodetic Coordinates on the Earth. The geocentric latitude, <J>', of a point, P, on the surface of the Earth is the angle at the Earth's center between P and the equatorial plane. The geodetic or geographic latitude, <j>, is the angle between the normal to an arbitrarily defined reference ellipsoid (chosen as a close -approximation to the oblate Earth) and the equatorial plane. Astronomical latitude and longitude are defined relative to the local vertical, or the normal to the equipotential surface of the Earth. Thus, astronomical latitude is defined as the angle between the local vertical and the Earth's equatorial plane. Maximum values

Table L-6. The Upper Atmosphere of the Earth

ALTITUDE (KM)

MEAN KINETIC TEMPERATURE l°KI

DENSITY Ikg/m3)

SCALE HEIGHT (KM)

0 0

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