Please place here comments about bugs of the current version. I’ll do the same.
1. BUG : when a manual variation of Longitudine or Latitude of a site caused a switch to “Manual Entry” the linked horizon profile was not unloaded. SOLVED.
2. BUG : if DE441 is not installed inserting a date out of the domain of DE440 causes a loop of error windows. SOLVED.
3. BUG : when Windows 10 is configured (Screen Menu) to show everything magnified of 125% some controls are not shown correctly. This problem should be disappeared.
4. BUG : HORIZONTAL VIEW: when a ‘N’ ‘S’ ‘E’ ‘W’ button is pressed the Zoom Control and the Graphic Screen Zoom value are not synchronised. SOLVED.
Hi
I have just downloaded version 0.9.9.348R. Nice improvements and everything seems to be working fine. No more problems with closing windows (main or other ones) as with some previous versions. The implementation of Dynamic Ephemeris Terminal is an interesting feature.
Thank you for improving Uruk_One.
Regards.
Hi,
thanks for downloading. You should note a faster FTP connection for retrieving asteroids data, I’ve set some parameter that should do the trick. Fingers crossed though.
Alberto
Hi
JPL HORIZONS is now using DE441 instead of DE431.
So it is interesting to check the differences between DE441 and DE431.
Ephemeris Type : OBSERVER
Target Body : Moon [Luna] [301]
Observer Location : Geocentric [500]
Time Span : 4500BC-01-01 00:00:00 TT
Apparent RA & DEC, no refraction
DE441 : b4500-Jan-01 00:00 20 53 50.44 -13 20 46.0
DE431 : b4500-Jan-01 00:00 20 54 48.80 -13 17 36.1
Regards
Hi, better to avoid calculations where precession is involved because I’m not sure that Horizons uses the Vondrak model. That said, I will use the Astrometric Equatorial referred to the J2000 equinox, or better in this case ICRF v. 3.0
I scanned 4500 BCE and 9000 BCE:
BCE 4500-01-01 00:00 TT
Observer Ecliptic (Astrometric IERS/J2000)
HORIZONS : 02 30 37.64 +20 01 56.6 (ICRF 3.0)
URUKONE : 02h 30m 37.050s +20° 01′ 55.31″
BCE 9000-01-01 00:00 TT
HORIZONS : 17 22 21.99 -25 16 56.2
URUKONE : 17h 22m 22.296s -25° 16′ 56.23″
This has taken away any doubt about some possible mistake of mine on the lunar orbit, it actually diverges from that of the DE431 in the way also calculated by me.
An update on https://ssd.jpl.nasa.gov/?horizons_news
April 12, 2021
— Version 4.80
* Horizons has been switched to use the new JPL DE441 planetary
ephemeris for planetary barycenters, Sun, and Moon (objects 0-10,
301 and 399. For details, see “The JPL Planetary and Lunar
Ephemerides DE440 and DE441”, R.S. Park, et al., The Astronomical
Journal, 161:105 (15pp), 2021 March.
* The current 1.1 million asteroid and comet solutions are being refit
for dynamical consistency with DE441 perturbations. The new solutions
will filter into the database over the next days. Due to the addition
of KBO mass in DE440/441, the SSB has shifted about 100 km, so SPK
file users should use a planetary ephemeris consistent with their
small-body SPK files. The PEs in SPK form may be retrieved here:
ftp://ssd.jpl.nasa.gov/pub/eph/planets/bsp/de430t.bsp
ftp://ssd.jpl.nasa.gov/pub/eph/planets/bsp/de440.bsp
Note: “DE440” is a shorter version of DE441, “DE430t” a shorter
version of the now-replaced DE431.
* The set of 16 most massive asteroid perturbers used for small-body
numerical integrations has also been updated. The new set is:
1 Ceres, 2 Pallas, 3 Juno, 4 Vesta, 7 Iris, 10 Hygiea, 15 Eunomia,
16 Psyche, 31 Euphrosyne, 52 Europa, 65 Cybele, 87 Sylvia,
88 Thisbe, 107 Camilla, 511 Davida, 704 Interamnia.
* Perturbing masses (GMs) used in Horizons small-body integrations are
available here: ftp://ssd.jpl.nasa.gov/pub/xfr/gm_Horizons.pck
* The “delta-t” (TT-UT1) calculation for dates prior to 1962 been
updated to the v.2020 model of Morrison et al (Feb. 2021 release).
Thanks for the info 🙂
Hi
In the article The JPL Planetary and Lunar Ephemerides DE440 and DE441, Ryan S. Park et al. 2020, it is stated :
For the orientation of Earth, the Vondrak precession model has been used (Vondrak et al. 2011), which, according to Vondrak et al. (2009), is more accurate for integrations beyond ±1000 years than the Lieske precession model (Lieske 1979) used for DE430. For the Moon, the effect of geodetic precession on lunar librations has been added as well as the solar radiation pressure force on the Earth–Moon system orbits.
Regards.
Hi,
it’s ok, that’s referred to internal DE441 management, but since raw data from DE441 are presented at the ICRF/J2000 equinox, both Horizons and I have to apply a further precession matrix to arrive at the apparent position at the equinox of date, that could be P03, Vondrak or else. So we actually should know which precession model Horizons applies to see if matches with mine (Vondrak). I’m going to check it out.
Just found on the Horizons manual:
PRECESSION MODEL:
For the time-span of 1799-Jan-1 to 2202-Jan-1, the IAU 1976 precession model of Lieske is used [16]. As published, this model is valid for only ~200 years on either side of the J2000.0 epoch. This is due to round-off error in the published coefficients and truncation to a 3rd order polynomial in the expressions for the Euler rotation angles. Therefore, outside this interval, the long-term precession and obliquity model of Owen [17] is used to maintain accuracy in the calculation of apparent (“of-date”) quantities.
The documentation on https://ssd.jpl.nasa.gov/?horizons_doc applies to Version 4.50 (December 10, 2019). However, https://ssd.jpl.nasa.gov/?horizons_news applies to version 4.80 so maybe we have to wait for an update of the documentation regarding the precession model. Wait and see…
Regards
An update regarding HORIZONS on Twitter :
https://twitter.com/astrokiwi/status/1380615258625089541
So it will take some days for updating small bodies…
Regards
The SSB moved 100Km and… et voilà, here’s something that will keep the Horizons team busy for a while 🙂
Buongiorno
Fino all’altro ieri non avevo mai avuto problemi ad utilizzare la versione attuale (0.9.9.348R), ma adesso mi appare la scritta “You are out of range of Ephemeris. Resetting” e quindi non riesco ad utilizzare la schermata con i relativi dati che aggiornati. Grazie
L. Torlai
Così non ho molti elementi per giudicare. Lo fa sempre appena l’applicazione parte? Solo quando si chiede una data nuova di calcolo? Sui led in alto a destra come è segnalata la DE441, non riconosciuta o installata? Succede tentando di ricaricare un evento salvato in precedenza?
In ogni caso provi a premere il bottone [ Now ] e vedere se il blocco sparisce.