logo Artsat ephemerides

Overview of tools for asteroid observers on this site

Use the form below to get ephemerides for artificial satellites. You can enter an artsat designation, and/or click on the check-boxes for various artsats listed below. The artsats with check-boxes are some high-altitude objects that occasionally get mistaken for asteroids. You can generate ephems for any catalogued artsat, including those in low-earth orbit, but much of this service is oriented toward the asteroid hunting community. We're usually tracking the high-altitude stuff.

You can, of course, select multiple objects and get ephemerides for each of them.

Please note that this is a work in progress. At some point, there should be an option to suppress daytime and below-the-horizons ephems. Ephemerides in JSON output would be an aid to automation.

Ephemerides are generated using the same TLEs (Two-Line Elements) as are used for the artsat identification tool, and have roughly the same limitations. Like that tool (and basically all tools on this site), source code is freely available, and you can build the code to run on your own machine instead of/as well as an on-line service.

Satellite ID : (example : 44432, 19040A, 2019-040A)

...and/or tick some of the boxes below, listing some of the more commonly searched-for objects :

Queqiao-2 booster Queqiao-2 spacecraft
Queqiao-2 sub-satellite (Tiandu-1 or -2) 2011-037A = NORAD 37755 = Spektr-R
2021-130A = NORAD 50463 = JWST Euclid = NORAD 57217 = 2023-092A
2008-051A = NORAD 33401 = IBEX Euclid booster = NORAD 57218 = 2023-092B
2019-040A = NORAD 44432 = Spektr-RG 2018-038A = NORAD 43435 = TESS
2013-074A = NORAD 39479 = Gaia 2013-070B = NORAD 39459 = Chang'e 3 booster
2018-103B = NORAD 43846 = Chang'e 4 booster 2024-006B = NORAD 58752 = Peregrine Centaur
1973-078A = NORAD 06893 = IMP-8 1972-073A = NORAD 06197 = IMP-7

Ephemeris starting date : UTC (Universal Time)

Don't round to nearest ephemeris step

Number of steps : Step size :

Step size can be, e.g., .1 or 2h or 0.5h or 10m or 15s. (The first would correspond to a 0.1-day = 2.4 hour step size.)

MPC observatory code or lat/lon :

Enter either a three-character MPC code or, for example, 'n44.01,w69.9' or 'e133.781,s33.27,130m'.

Show apparent motion in "/min = '/hr (default is "/sec='/min)
Also show separate motions in RA and dec
Show dates/times as MJD (instead of calendar format)
Output J2000 equatorial state vectors (instead of observables)

Ephemeris starting date : This is quite flexible. 'now' is the default, but one can provide dates such as '2014 dec 25', 'Feb-13 3:00', '2015/2/13 03:14:15.9', and it will be interpreted properly. (Note that one shouldn't get too sloppy; '2015-5-6' could be either May 6 or June 5, and '05-06-07' could be interpreted as a (two-digit) year, month, and day in any of six orders, probably but not definitely in the 21st century. Caveat user. I usually go with a four-digit year and three-character month; "2015 Feb 18" is unambiguous, no matter how you scramble the pieces. But essentially, if a human can figure it out, this program should be able to.)

Input such as 'MJD 12345.6', 'jd 2451545', 'now+3h', and 'Wed 3:14:16 PM' will also work; click here for the full list of time input options.

Step size: This defaults to being in days, but input such as '2h' will lead to a two-hour ephemeris step size, or '10m' for a ten-minute step size. One can use '.1' to get a step size of a tenth of a day, and so forth. Negative step sizes will result in a backwards-running ephemeris.

MPC code: This defaults to 500, for a geocentric ephemeris. But it can be any of nearly 2000 three-character observatory codes assigned by the MPC. Or, as shown, you can specify a lat/lon and, optionally, an altitude.

Contact info

I can be reached at p‮ôç.ötulpťcéjôřp@otúl‬m. If you're a human instead of a spambot, you can probably figure out how to remove the diacritical marks...