Questions tagged [jpl-horizons]
Questions relating to the JPL Horizons solar system data and ephemeris computation service
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How to calculate the planets and moons beyond Newtons's gravitational force?
The question Calculating the planets and moons based on Newtons's gravitational force was pretty much answered with two items:
Use a reasonable ODE solver; at least RK4 (the classic Runge-Kutta ...
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Is this what station keeping maneuvers look like, or just glitches in data? (SOHO via Horizons)
I've been enjoying the JPL Horizons web interface and after I discovered the incredibly extensive database associated with SOHO (Solar and Heliospheric Observatory, also see sohowww.nascom.nasa.gov) ...
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Getting state vectors from JPL Horizons ephemerides
I'm simulating the Sun-Earth-Moon system by numerical integration of equation of motion.
I've confused a little bit in JPL Horizons ephemerides.
Could anyone explain (if possible, on pictures), how ...
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Unravelling Cassini's "ball of yarn" orbit around Saturn, tabulation of propulsive maneuvers?
The cool GIF on the NASA JPL Cassini resources page All Orbits (2004-2017): The Ball of Yarn is quite beautiful to look at, but it also hints at some beautiful engineering and orbital mechanics as ...
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Juno's original orbit around Jupiter - is this apsidal precession? If so, need expression
Below is a plot of Juno's originally planned orbit around Jupiter, extracted from JPL Horizons. It's shown in J2000 ecliptic coordinates, centered on the Jupiter barycenter. It turns out the orbit is ...
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JPL Horizons original reference orbit data for Juno - how to retrieve now that it's been updated?
Because of the slow helium valve responses, Juno was not instructed to execute the large delta-v maneuver to drop from the ~53 day orbit to the ~14 day orbit originally scheduled for 2016-Oct-19.
I'd ...
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Why do the LRO's orbital elements appear to constantly oscillate - except recently?
I plotted some of the orbital elements of the Lunar Reconnaissance Orbiter from JPL's Horizons database, and I see that there are constant oscillations. The period of the semi-major axis and ...
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Is Cassini's 183rd burn; some kind of engine record?
I've just read that when Cassini makes its first close pass of Saturn's F-ring on December 4, it will be the 183rd engine burn which sounds like a lot for orbital maneuvers using a spacecraft's main ...
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I've almost learned to spell Chebyshev, why has JPL switched to Hermite interpolation for DE438?
According to @ChrisR's thorough answer
One caveat however is that the interpolation in DE438 is a Hermite interpolation, and no longer a Chebychev interpolation, so you may need to update your code....
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Does JPL's Horizons have better MU69 state vectors for the New Horizons flyby somewhere?
Today I downloaded the state vectors for New Horizons and MU69 Arrokoth and subtracted their positions. The two new get closer than about 596,000 kilometers.
The New Horizons output header says:
<...
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Why hasn't DSCOVR's trajectory determination been updated in JPL's Horizons after 2015-Aug-4?
I tried to download orbital positions for the DSCOVR spacecraft in its Lissajous orbit around Sun-Earth L1 from JPL's Horizons web page but I was surprised to see the following!
No ephemeris for ...
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How to find instantaneous mass of a central body that results in a given osculating orbit?
This question was underspecified, so I'm going to try again.
Osculating orbital elements are Keplerian elements of a hypothetical orbit around a specified center which would be tangent to a specified ...
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Why does this plot show Starman's speed relative to the Sun fluctuating so often?
After the launch of Starman, during the inaugural flight of SpaceX's heavy lift vehicle, the Falcon Heavy, PearsonArtPhoto set up a website to track various stats about Starman and his Roadster.
A ...
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Where to find the best values for standard gravitational parameters of solar system bodies?
Where can I find the best values to use for standard gravitational parameters of solar system bodies for numerical simulation experiments?
Here are two sets I've put together. The first set is from ...
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How do we track the exact location of the spacecraft which is millions or billions of miles away from us?
How do we track the exact location of the spacecraft which is millions or billions of miles away from us? What things do we study for tracking purpose? How exactly do we predict?
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How to show spacecraft position, heading etc relative to an asteroid
Given all the cool asteroid and comet missions out there (OSIRIS-REx, Hayabusa2, etc) I want to track the approach of the spacecraft to the asteroid.
My favorite tool, JPL Horizons, can provide highly ...
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What was Chang'e-2's 3D orbit in space? (since it's not in Horizons)
edit: A simple web search in Chinese may turn up something, but I don't know anyone personally who is both both fluent and interested in space exploration. This is a pretty cool orbit - there must be ...
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Why aren't there any trajectories for the Viking missions in JPL Horizons' database?
Horizons has calculated trajectories for deep space spacecraft, including six objects related to Apollo 8 through 12.
See an (old) list in the currently unanswered question What was Chang'e-2'...
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How can the data rate be increased in noisy outer space?
What can we do to improve the data rate in outer space? I see that there are some noise sources that affect the signal quality between ground stations & deep space.
As I've read so far in various ...
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Access to Chebyshev coefficients from JPL ephemerides
I want to generate an ephemeris file containing the Chebyshev coefficients, similar to how we can generate ephemeris file of positions with Horizon tool (https://ssd.jpl.nasa.gov/horizons/app.html#/). ...
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Compatibility of osculating elements and cartesian vectors given by JPL Horizons?
I'm facing a problem I can't explain and I would like to know if someone has more information about it.
I'm drawing a solar system and when I plot earth with the Horizon cartesian coordinates, it ...
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How to obtain Chebyshev coefficients directly from the JPL Horizon's interface?
I'm from Spain and I'm currently finishing my degree in Aerospace Engineering.
I am starting with all of this. My objective is to obtain the Chebyshev coefficients for the major planets position, ...
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How exactly to use astroquery.jplhorizons to get the state vectors of Mercury and the Parker Solar Probe?
In the question Is the Parker Solar Probe's semimajor axis being so close to that of Mercury's just coincidence? Does it help somehow? I used a Python script to plot the heliocentric orbit of the ...
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Is it posible to convert JPL Horizons Vectors to ECEF?
I'm needing to accurately find the sun and moon position in ECEF and I'm wanting to make use of JPL's Horisons VECTORS to do this.
What data should I export from the web interface and how should I ...
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Was the famous SPICE package of programs, utilities and data kernels named after "Melange" found on the planet Arrakis?
This question is NOT about a fictional planet:
This question is about NASA JPL history and the naming of SPICE. It is not primarily about the fictional planet Arrakis nor the fictional drug Melange ...
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Will these equations give me the approximate apparent RA and Dec using positions from Horizons?
In this answer @DavidHammen showed me how to get coordinates from JPL's Horizons using the Earth's equatorial plane as a reference plane by selecting
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Why is the sidereal period of the Earth 362.392667 days?
Using JPL's Horizons API I can look at the orbital elements for the EM Barycenter wrt the Solar System Barycenter at J2000. The output looks like this:
Watch for the PR (Sidereal orbit period) ...
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Python API for JPL Horizons?
I found the python package HorizonJPL in the Python Package Index, but it looks like it's limited to activity in 2013. When I go to the linked documentation page https://docs.google.com/document/d/...
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How does JPL define the exact position of Lagrange points in the real solar system where (I thought that) they can't be defined?
My answer to Does the distance to L2 vary? is
The correct answer is "No, they are only mathematically defined when the orbit is circular".
but @DavidHammen's answer explains that they can ...
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How is the Chebyshev method used by JPL?
In the DE packages, NASA gives us a series of coefficients for the Chebyshev approximation.
As I understand it, those approximations are given by a series of polynomials $T_n$ for the interval $[-1,1]$...
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How to calculate earth's precession using JPL Horizons System?
I'm new to JPL Horizons and understanding how to use the tool efficiently.
I'm looking to extract earth's precession data and understand where we are in the current cycle. I understand we progress 1 ...
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What are the problems that need to be taken in consideration when trying to find planetary position by using jpl ephemerides?
I'm currently trying to determine the position of the sun and the moon from jpl ephemeris DE200 which is referred to the dynamical equator and equinox of 2000 and uses tdb time. I am using the j2000 ...
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Discrepancy between HORIZONS and SPICE
I am trying to reproduce the output of the HORIZONS system using the SPICE toolkit from NASA, but I am not getting exactly the same results. I am using this script to compute the position and velocity ...
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Horizons ephemeris - how did they calculate that “Keplerian GM” value?
I’ve been playing with the NAIF’s SPICE library for some time (CSPICE in particular). In order to obtain the state vector of an asteroid from its osculating elements, I’m calling the “conics_c” ...
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Calculating spacecraft thrust manoeuvres with JPL data
I've recently programmed an animated simulation of the main elements (core planets and Sun) of our solar system: by using the initial coordinates from the JPL (Jet Propulsion Laboratory - NASA) ...
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Generating JPL HORIZONS parameters for use with JPL HORIZONS itself
I want to be able to calculate RA/Dec for a given body with JPL HORIZONS, using a heliocentric specification of the orbital elements for a small solar system body (say, Apophis), but instead of using ...
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What does "coord@10" mean exactly as a target for JPL's Horizons? How to access it?
According to this answer, using "coord@10" as a target code for JPL's Horizons represents the motion of a hypothetical location on the Sun's surface; presumably as a way to represent the rotation of ...
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Why does this site show Starman's position so far from what Horizons gives?
As this answer mentions, there have been several questions about the data represented on the whereisroadster site within the Space Exploration Stack Exchange site.
One about wrong distances has been ...
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Help with ISEE-3's historic L1 halo orbit's Spice kernels (1978-82); still available somewhere online?
When I was looking for previous calculations for JUNO I received help which pointed me here.
Now I'd like to review ISEE-3's orbit and compare it to calculations since receiving this welcomed answer.
...
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Ephemeris for lunar body-centered body-fixed coordinates?
I'm going to try to do a modest simulation of the Moon's libration as seen from the Earth (geocenter), similar to the technical one's I've shown in this question. I'll do it in Python and render it in ...
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How can I find the old reference orbit for JWST (from 2014) and get AltAz positions from Earth without learning Spice? Can Horizons do it? Can Python?
In this ancient 2017 answer to What happens to JWST after it runs out of propellant? I've plotted an eleven year long reference orbit for JWST that was available form Horizons at the time.
Now that ...
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Why is the highest speed that Voyager 2 achieved from the Jupiter gravity assist not at perijove?
I plotted some data of the speed of Voyager 2 for various times (around the Jupiter flyby) and noticed that the highest speed that Voyager achieved was not at perijove and was wondering why this might ...
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JPL ephemerides: effect of Saturn, Uranus and Neptune
According to the Folkner ( Folkner et al, 2014, The Planetary and Lunar Ephemerides
DE430 and DE431, IPN Progress Report 42-196 • February 15, 2014), JPL ephemerides consider the following effects:
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How to know when JPL Horizons is updated with new Juno spacecraft trajectory?
I "watched" Juno's flyby of Jupiter using the simulation in the NASA's Eyes app on my laptop, and later saw the good news in this tweet. Now I want to do a "flyby in Python".
Using the setup (shown ...
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Where are post-2017 EPIC images of Earth and the DSCOVR spacecraft coordinates available for download?
I tried to download orbital positions for the DSCOVR spacecraft in its Lissajous orbit around Sun-Earth L1 from JPL's Horizons web page but I was surprised to see the following!
No ephemeris for ...
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How to find Horizons ephemerides or Spice kernels for the cis-lunar halo orbits of the Themis B & C) spacecraft?
The Themis spacecraft B and C have been renamed ARTEMIS P1 and P2 and moved around in cis-lunar space from Earth orbit to Lunar orbit.
This transfer involved libration point orbits, as discussed in ...
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