HORIZONS Web-Interface
Current Settings
Ephemeris Type [change] : | OBSERVER |
Target Body [change] : | Mars [499] |
Observer Location [change] : | Geocentric [500] |
Time Span [change] : | Start=2009-01-17, Stop=2009-02-16, 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
Specify Observer Coordinates
Longitude and Latitude can be entered as either
"degrees minutes seconds" or decimal degrees.
In either case, they should alway 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.
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