Skip Page Navigation
NASA JPL Caltech
NASA Logo - Jet Propulsion Laboratory + View the NASA Portal
+ Near-Earth Object (NEO) Program
Search JPL
JPL Home Earth Solar System Stars & Galaxies Technology
JPL Solar System Dynamics
HORIZONS Web-Interface
This tool provides a web-based limited interface to JPL's HORIZONS system which can be used to generate ephemerides for solar-system bodies. Full access to HORIZONS features is available via the primary telnet interface. HORIZONS system news shows recent changes and improvements. A web-interface tutorial is available to assist new users.

Current Settings

Ephemeris Type [change] :  OBSERVER
Target Body [change] :  Mars [499]
Observer Location [change] :  Geocentric [500]
Time Span [change] :  Start=2016-05-05, Stop=2016-06-04, Step=1 d
Table Settings [change] :  defaults
Display/Output [change] :  default (formatted HTML)

Specify Observer Location:

You can specify a topocentric observer location by choosing from a list of major world cities, by choosing from a list of world-wide observatories, or by giving the latitude, longitude, and altitude. You can also specify non-topocentric Horizons-specific location codes such as the sun or another planet.

Please select from from the following list:

Lookup Named Location


Use observatory code numbers (if you know them) or names. For example, enter "675" to select the Palomar Mountain main site. Or, enter "palomar" for a list of matching sites. Use "Geocentric or code "500" for geocentric. You can also enter Horizons-specific non-topocentric location codes. For example, use "@sun" to place the observer at the center of the sun, "@0" to select the solar-system barycenter, or "Viking 1@499" to select the Viking 1 landing site on Mars (499). To see all sites available for a specific body, use "*@body" where body is body ID. For example, "*@499" will show all sites on Mars. See the Horizons documentation for more details on center/observer location codes.

Choose from a List


    or     :

Specify Observer Coordinates

Longitude and Latitude can be entered as either "degrees minutes seconds" or decimal degrees. In either case, they should always be positive and use the appropriate East/West and North/South selections. If entering "degrees minutes seconds" use spaces or commas between elements. If Altitude is unknown, zero can be used for optical sites without much loss of accuracy.

Longitude: (degrees )
Latitude: (degrees )
( above the reference ellipsoid {WGS-84, or approx. sea level for Earth})
Body ID: (Horizons body ID of the central body: e.g. '399' for Earth, '499' for Mars)

FirstGov 2016-May-05 10:25 UT
(server date/time)  
NASA Home Page
Site Manager:   Ryan S. Park
Webmaster  Alan B. Chamberlin