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In astronomy and celestial navigation, an ephemeris (/ ɪ ˈ f ɛ m ər ɪ s /; pl. ephemerides / ˌ ɛ f ə ˈ m ɛr ɪ ˌ d iː z /; from Latin ephemeris 'diary', from Ancient Greek ἐφημερίς (ephēmerís) 'diary, journal') [1] [2] [3] is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position ...
The 'reduced accuracy' DE406 ephemeris gives an interpolating precision (relative to the full ephemeris values) no worse than 25 metres for any planet and no worse than 1 metre for the Moon. Note that these precision numbers are for the interpolated values relative to the original tabulated coordinates.
A secondary cause for the increase in Satellite Catalog Numbers was the commercialization of space and break-up events and collisions that have created debris objects. [17] Adaptations of the TLE were considered to extend the number of encodable Satellites within the TLE but instead a new format, the CCSDS OMM (Orbit Mean-Elements Message ...
The inverse transformation, which computes the 3 coordinates in the I-J-K system given the 3 (or 2) coordinates in the x-y-z system, is represented by the inverse matrix. According to the rules of matrix algebra , the inverse matrix of the product of the 3 rotation matrices is obtained by inverting the order of the three matrices and switching ...
There are two navigation message types: LNAV-L is used by satellites with PRN numbers 1 to 32 (called lower PRN numbers) and LNAV-U is used by satellites with PRN numbers 33 to 63 (called upper PRN numbers). [9] The two types use very similar formats. Subframes 1 to 3 are the same, [10] while subframes 4 and 5 are almost the same. Each message ...
The galactic coordinate system uses the approximate plane of the Milky Way Galaxy as its fundamental plane. The Solar System is still the center of the coordinate system, and the zero point is defined as the direction towards the Galactic Center. Galactic latitude resembles the elevation above the galactic plane and galactic longitude ...
In the case of the most current ephemerides, it is a relativistic coordinate time scale equivalent to the IAU definition of TCB. [3] In the past, mean solar time (before the discovery of the non-uniform rotation of the Earth) and ephemeris time (before the implementation of relativistic gravitational equations) were used. The remainder of the ...
A list of articles about numbers (not about numerals). Topics include powers of ten, notable integers, prime and cardinal numbers, and the myriad system.