Ephemeris Data
if you want to find exact position of solar system objects in the sky,one can use the best interface provided by nasa jpl horizon website ( http://ssd.jpl.nasa.gov/horizons.cgi ).
The Horizons On-Line Ephemeris System provides access to key solar system data and dynamic production of highly accurate ephemerides for solar system objects. This includes 611,000+ asteroids, 3200 comets, 176 natural satellites, all planets, the Sun, more than 60 select spacecraft, and dynamical points such as Earth-Sun L1, L2, L4, L5, and system barycenters. Users may conduct parameter searches of the comet/asteroid database, finding objects matching combinations of up to 42 different parameters. Users may define and integrate their own objects. Rise, transit and set may be identified to the nearest minute. When used with Sun and Moon sky-brightness data, observing windows can be identified. Close-approaches by asteroids and comets to the planets, Ceres, Pallas, and Vesta, can be rapidly identified along with the encounter uncertainties and impact probabilities. Orbital uncertainties can be computed for asteroids and comets.
both topocentric and geocentric observers, in one of 9 coordinate systems and 4 time scales (CT, TT, UT, Civil). 1500
Earth station locations are available, along with sites on other major bodies. Users may search for (or define)
topocentric site coordinates on any planet or natural satellite with a known rotational model. Spacecraft-based
observations are also supported. Output is suitable for observers, mission planners and other researchers, although this
determination is ultimately the user's responsibility. The underlying planet/satellite ephemerides and small-body
osculating elements are the same ones used at JPL for radar astronomy, mission planning and spacecraft navigation.
In addition to parameter searches, object data summaries, and close-approach tables, four types of
customizable ephemerides can be requested:
1) Observables (RA/DEC, Az/El, physical aspect, separation angles, uncertainty ellipses,etc.)
2) Osculating elements
3) Cartesian state vectors
4) SPK binaries (asteroids and comets only)
The first three are ASCII tables; output is returned to the user via browser, e-mail, FTP or Kermit protocols and
may be requested in a format suitable for spreadsheet import. SPK binary files allows user programs to reproduce the
integrated target state at any instant and may be used as plug-ins to existing visualization and mission-design software.
below is the sample data from Banglore Location on Target Body Venus.
i use mainly for Right Ascension and Declination data.
