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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=
2008-09-21
, Stop=
2008-10-21
, Step=
1
d
Table Settings [
change
] :
defaults
Display/Output [
change
] :
default
(formatted HTML)
Table Settings
Select observer quantities from table below:
[
switch to manual-entry list-of-numbers form
]
Optionally preset observer quantities selection using one of the following:
1.
Astrometric RA & DEC
15.
Sun sub-long & sub-lat
29.
Constellation ID
* 2.
Apparent RA & DEC
16.
Sub Sun Pos. Ang & Dis
30.
Delta-T (CT - UT)
3.
Rates; RA & DEC
17.
N. Pole Pos. Ang & Dis
* 31.
Obs eclip. lon & lat
* 4.
Apparent AZ & EL
18.
Helio eclip. lon & lat
32.
North pole RA & DEC
5.
Rates; AZ & EL
19.
Helio range & rng rate
33.
Galactic latitude
6.
Sat. X & Y, pos. ang
20.
Obsrv range & rng rate
34.
Local app. SOLAR time
7.
Local app. sid. time
21.
One-Way Light-Time
35.
Earth->Site lt-time
8.
Airmass
22.
Speed wrt Sun & obsrvr
> 36.
RA & DEC uncertainty
9.
Vis mag. & Surf Brt
23.
Sun-Obsrvr-Target angl
> 37.
POS error ellipse
10.
Illuminated fraction
24.
Sun-Target-Obsrvr angl
> 38.
POS uncertainty (RSS)
11.
Defect of illumin.
25.
Targ-Obsrv-Moon/Illum%
> 39.
Range & Rng-rate sig.
12.
Sat. angle separ/vis
26.
Obsr-Primary-Targ angl
> 40.
Doppler/delay sigmas
13.
Target angular diam.
27.
Pos. Ang;radius & -vel
14.
Obs sub-lng & sub-lat
28.
Orbit plane angle
Notes:
*
affected by apparent position estimation (atmospheric refraction model, see below)
>
requires object orbit covariance
Observer quantities are described in the
HORIZONS documentation
.
Optional observer-table settings:
date/time format :
Calendar Date/Time
Julian Day
Both
-- display date/time in year-month-day and/or Julian-day format
time digits :
minutes (HH:MM)
seconds (HH:MM:SS)
fractional seconds (HH:MM:SS.SSS)
-- controls output precision of time
angle format :
hours/degrees minutes seconds
decimal degrees
-- select RA/Dec output format
output units :
km & km/s
km & km/d
AU & AU/d
-- units for most output quantities
range units :
Astronomical Units
Kilometers
-- units for range-type quantities
refraction model :
airless model (no refraction)
standard atmosphere refraction model
-- select atmospheric refraction model
airmass limit :
-- suppress output when airmass is greater than this limit
elevation cutoff :
(deg) -- suppress output when object elevation is less than this limit
solar elong. limits :
-
(deg) -- suppress output when solar elongation is outside this range
suppress range-rate :
-- suppress range-rate for range/range-rate output
skip daylight :
-- suppress output during daylight
extra precision :
-- output addition digits for RA/Dec quantities
RTS flag :
disable
true visual horizon
geometric horizon
radar horizon
-- output data only at target rise/transit/set (RTS)
reference system :
ICRF/J2000.0
FK4/B1950.0
-- reference frame for geometric and astrometric quantities
CSV format :
-- output data in Comma-Separated-Variables (CSV) format
object page :
-- include object information/data page on output
2008-Sep-21 08:19 UT
(server date/time)
Site Manager:
Donald K. Yeomans
Webmaster
:
Alan B. Chamberlin
