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Specify Observer Location:
Set observer location (the "coordinate origin") using one of the three optional sections below.
Specify a topocentric observer location by choosing from
a list of predefined astronomical observatories,
major cities on Earth,
major sites on other solar system bodies,
or by giving the latitude, longitude, altitude, and solar system body.
Body-centered (non-topocentric) sites throughout the solar system (such as the Sun, planet, satellite, or spacecraft centers) can also be specified using body names or codes as described below.
Use unique observatory code numbers (if you know them) or names
(which may result in a list to choose from if the name is not unique).
"675" select the Palomar Mountain main site
"Palomar" list of matching names to select from
You may also enter pre-defined, non-topocentric observation points and locations
for all major bodies in the solar system here.
"500" Earth's center (same as "geocentric")
"@sun" center of the Sun
"@0" solar system barycenter (same as "@ssb")
"Viking 1@499" Viking 1 landing site on Mars (body 499)
"@hst" Hubble Space Telescope (same as "@-48")
"@-32" Voyager 2 spacecraft
"@301" center of the Moon
"Apollo 11@301" Apollo 11 landing site on the Moon's surface
"@phobos" center of Phobos, the Martian moon (same as "@401")
To see all sites available for a specific body, use "*@body" where body is body ID.
For example, "*@499" will show all pre-defined sites on Mars.
See the Horizons documentation
for more details on center/observer location codes.
Choose From a List of Predefined Sites on Earth
Specify Origin: Topocentric 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.