Juno/Jupiter Ephemeris Generator Help
This form enables you to generate a table listing useful information
about the viewing geometry for Jupiter and/or any of its moons as a
function of time. You are free to specify which of a variety of useful
quantities to tabulate. The file returned will contain a single header
line describing each column, followed by one row of numbers for each
time step.
Change History
1.0 (January 28, 1997):
Original Jupiter Ephemeris Generator on line.
1.1 (February 6, 1997):
Added optional columns for sub-solar and inertial sub-Earth longitudes.
1.2 (February 11, 1997):
Added a new ephemeris option ("Pre-RPX #2").
2.0 (January 12, 1999):
Added sub-solar and sub-Earth latitude/rotating longitude options.
Revised user interface.
Added a new ephemeris option ("Post-Galileo").
2.1 (January 31, 2002):
Introduction of the Ephemeris Generator for Cassini.
Added a new ephemeris option ("Post-Galileo #2"). Also expanded the
ephemeris time limits for the small satellites.
2.2 (January 10, 2003):
Added a new column option providing second accuracy in time tags.
2.3 (December 1, 2009):
Updated the ephemeris and removed the option to select outdated ephemerides.
2.5 (January 23, 2013):
Raised the maximum number of output lines to 10,000.
Renumbered for consistency across all the Ephemeris Generator tools.
Ephemeris updates.
2.6 (January 4, 2016):
Ported to new server.
Ephemeris updates.
2.7 (October 14, 2020):
Ephemeris updates.
2.8 (June 20, 2021):
Ephemeris updates; introduction of the Ephemeris Generator for Juno.
3.0 (August 2, 2022):
Major new features:
- the selection of available columns has been expanded and standardized
across all Ephemeris Generator tools.
- Ephemeris Generator requests can now be bookmarked.
- the new Output option lets you jump directly to the table,
bypassing the web page.
- JWST, HST, and Earth-based observatories are now supported.
- the form now uses a clean, new style sheet.
The start and stop times (UTC) of the table can be entered in a variety
of formats. For example, the following all parse to 0:01:02 UTC on July
4, 1976:
- 1976-JUL-04 00:01:02.00
- July 4, 1976 12:01:02 am
- 12:01:02 am July 4, 1976
- 1976-07-04T00:01:02Z (ISO format)
- MJD 42963.00071759259
- JD 2442963.50071759259
If you want the gory details of how times are interpreted, click
here.
Enter the time interval to be used for the tabulation as a number in the box,
and select the time unit from the choices provided.
Click on the box to the left of each quantity or set of quantities that
you wish to tabulate. The order of the columns in the table will match
the order listed on the form. Possible selections are as follows:
-
Modified Julian Date
Adds a column containing the Modified Julian Date, a common method
of designating dates and times in astronomy. MJD is equal to the number
of (possibly fractional) days elapsed since 0:00 UTC on 17 November
1858.
-
Year, Month, Day, Hour, Minute
Adds five columns containing the UTC date (year, month, day) and time
(hours, minutes) as integers.
-
Year, Month, Day, Hour, Minute, Second
Adds six columns containing the UTC date (year, month, day) and time
(hours, minutes, seconds) as integers.
-
Year, DOY, Hour, Minute
Adds four columns containing the UTC date (year and day-of-year) and time
(hours, minutes) as integers.
-
Year, DOY, Hour, Minute, Second
Adds five columns containing the UTC date (year and day-of-year) and time
(hours, minutes, seconds) as integers.
-
Observer-Jupiter distance
Adds a column containing the distance between the observer and
Jupiter, in km.
-
Sun-Jupiter distance
Adds a column containing the distance between the Sun and
Jupiter, in km.
-
Jupiter phase angle
Adds a column containing the phase angle of Jupiter as seen
from the observer, in degrees.
This is equal to the Sun-Jupiter-observer angle.
-
Ring opening angle to the observer
Adds a column containing the ring plane opening angle to the observer, in
degrees. This is equivalent to the planetocentric sub-observer latitude at
Jupiter; it equals zero during a ring plane crossing.
-
Ring opening angle to the Sun
Adds a column containing the ring plane opening angle to the Sun, in
degrees. This is equivalent to the planetocentric sub-solar latitude at
Jupiter; it equals zero during a ring plane crossing.
-
Sub-observer inertial longitude
Adds a column containing the sub-observer longitude at Jupiter, in
degrees. This is measured from the J2000 ascending node of the planet's
equatorial plane. Note that it is an inertial longitude, not measured
in a frame rotating with the planet.
-
Sub-solar inertial longitude
Adds a column containing the sub-solar longitude at Jupiter, in
degrees. This is measured from the J2000 ascending node of the planet's
equatorial plane. Note that it is an inertial longitude, not measured
in a frame rotating with the planet.
-
Sub-observer latitude and rotating longitude
Adds a pair of columns containing the sub-observer planetocentric latitude and
longitude at Jupiter, in degrees. This is measured in a frame rotating
with the planet.
-
Sub-solar latitude and rotating longitude
Adds a pair of columns containing the sub-dolst planetocentric latitude and
longitude at Jupiter, in degrees. This is measured in a frame rotating
with the planet.
-
Jupiter RA and Dec
Adds two columns containing the J2000 right ascension and
declination of Jupiter. RA is tabulated in units of hours;
declination is in units of degrees.
-
Earth RA and Dec
Adds two columns containing the J2000 right ascension and
declination of the Earth. RA is tabulated in units of hours;
declination is in units of degrees.
-
Sun RA and Dec
Adds two columns containing the J2000 right ascension and
declination of the Sun. RA is tabulated in units of hours;
declination is in units of degrees.
-
Jupiter projected equatorial radius
Adds a column containing the projected equatorial radius of Jupiter
as seen from the observer, in degrees.
You may also include the positions of any set of moons in the
table. Any of these quantities can be tabulated for each moon:
-
Observer-moon distance
Adds a column containing the distance between the observer and
the moon, in km.
-
Moon phase angle
Adds a column containing the phase angle of the selected moon as seen
from the observer, in degrees.
-
Sub-observer latitude and rotating longitude
Adds a pair of columns containing the sub-observer planetocentric latitude and
longitude at the selected moon, in degrees. This is measured in a frame rotating
with the moon.
-
Sub-solar latitude and rotating longitude
Adds a pair of columns containing the sub-dolst planetocentric latitude and
longitude at the selected moon, in degrees. This is measured in a frame rotating
with the moon.
-
RA and dec
Adds a pair of columns containing the J2000 right ascension and
declination for each selected moon. RA values are given in units of
hours; dec values are given in degrees.
-
Offset RA and dec
Adds a pair of columns containing the positional offset of each selected moon
from the center of the planet. Values are given in units of degrees,
where the first value is the offset in the direction of increasing J2000
RA and the second is in the direction of increasing dec.
-
Orbital longitude relative to observer
Adds a column containing the orbital longitude of the selected moon
relative to the observer, in degrees. Zero indicates that the moon is between
the observer and the planet; 90 indicates that the moon is at the receding
ansa.
-
Orbit plane opening angle to observer
Adds a column containing the opening angle of the orbit plane as seen from
the observer, in degrees.
Click on the box to the left of each moon that you wish to
include in the table. Note that it is not necessary to include any
moon columns at all.
Juno/Jupiter
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Last updated August 3, 2022