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The ephemeris was more accurately oriented onto the ICRF. DE405 covered 1600 to 2200 to full precision. This ephemeris was utilized in the Astronomical Almanac from 2003 until 2014. DE406 was released with DE405 in 1998. A Long Ephemeris, this was the condensed version of DE405, covering 3000 BC to AD 3000 with the same limitations as DE404.
JPL Horizons On-Line Ephemeris System provides access to key Solar System data and flexible production of highly accurate ephemerides for Solar System objects. Osculating elements at a given epoch (such as produced by the JPL Small-Body Database ) are always an approximation to an object's orbit (i.e. an unperturbed conic orbit or a " two-body ...
From 1984, the Jet Propulsion Laboratory's DE series of computer-generated ephemerides took over as the fundamental ephemeris of the Astronomical Almanac. Obliquity based on DE200, which analyzed observations from 1911 to 1979, was calculated: ε = 23°26′21.45″ − 46.815″ T − 0.0006″ T 2 + 0.00181″ T 3
The Jet Propulsion Laboratory Development Ephemeris is a prime example. Conventional so-called analytical ephemerides that utilize series expansions for the coordinates have also been developed, but of much increased size and accuracy as compared to the past, by making use of computers to manage the tens of thousands of terms.
In the late twentieth and early twenty-first centuries, modern developments of lunar theory are being used in the Jet Propulsion Laboratory Development Ephemeris series of models of the Solar System, in conjunction with high-precision observations, to test the exactness of physical relationships associated with the general theory of relativity ...
Jet propulsion is produced by some reaction engines or animals when thrust is generated by a fast moving jet of fluid in accordance with Newton's laws of motion.It is most effective when the Reynolds number is high—that is, the object being propelled is relatively large and passing through a low-viscosity medium.
ELP gives a series expansion of the orbital elements and the coordinates of the Moon.The authors refer to it as a "semi-analytical" theory because they developed their expressions not purely symbolically, but introduced numerical values for orbital constants from the outset; but they also constructed partial derivatives of all terms with respect to these constants, so they could make ...
a better definition and practical realization of ephemeris time which would take advantage of atomic time; a new epoch to replace 1950.0 [11] It was decided to introduce as many changes as possible at one time in a consistent system, and the new system would go into effect for the 1984 edition of the ephemerides.