View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0002425 | SkyChart | 2-Catalog data | public | 21-04-19 02:37 | 21-04-20 11:55 |
| Reporter | Guillermo Abramson | Assigned To | Patrick Chevalley | ||
| Priority | normal | Severity | minor | Reproducibility | have not tried |
| Status | resolved | Resolution | fixed | ||
| Platform | PC | OS | Windows | OS Version | 10 64bit |
| Product Version | 4.3 beta | ||||
| Target Version | 4.4 | Fixed in Version | 4.3 beta | ||
| Summary | 0002425: Comet Hale-Bopp ephemeris off | ||||
| Description | Hi, Chris. While checking my old photos of comet Hale-Bopp I couldn't quite fix its position. I compared Cartes with JPL Horizons ephemerides and Cartes is off by several arcminutes (which correspond to almost (but not quite) 2 days. See screenshot. I also checked Stellarium, which gives a closer value to the JPL Horizons one. Also attached. I have not checked other comets, so I am not sure if the problem is in the catalog, or just in Hale-Bopp, or in the code. Thanks for Cartes, once more, and take care. Guillermo | ||||
| Steps To Reproduce | Check comet Hale-Bopp RA/DEC in March 1997 against JPL Horizons ephemerides (used ephemerides attached). | ||||
| Additional Information | I used topocentric coordinates at Trieste, which is where I made the photos. Cartes, Stellarium and JPL Horizons are set at Trieste, Italy (UT+2). | ||||
| Tags | No tags attached. | ||||
|
|
ephemerids.txt (14,445 bytes)
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] : Comet C/1995 O1 (Hale-Bopp) [2008]
Observer Location [change] : Trieste [038] ( 13�46'13.4''E, 45�38'35.8''N, 64.2 m )
Time Span [change] : Start=1997-03-15 19:00 UT, Stop=1997-04-15, Step=1 d
Table Settings [change] : defaults
Display/Output [change] : default (formatted HTML)
Object Data Page
JPL/HORIZONS Hale-Bopp (C/1995 O1) 2021-Apr-18 15:55:44
Rec #:90002089 (+COV) Soln.date: 2017-Oct-04_09:43:58 # obs: 39 (2005-2013)
IAU76/J2000 helio. ecliptic osc. elements (au, days, deg., period=Julian yrs):
EPOCH= 2454724.5 ! 2008-Sep-15.0000000 (TDB) RMSW= n.a.
EC= .9949607008417696 QR= .9174143409263262 TP= 2450538.4378482755
OM= 282.9487539423989 W= 130.662020526416 IN= 89.21708989130315
A= 182.0519703474959 MA= 1.679641786426175 ADIST= 363.1865263540654
PER= 2456.4124497891 N= .000401246 ANGMOM= .023271875
DAN= 5.20406 DDN= 1.11035 L= 102.0374188
B= 49.3317479 MOID= .116025 TP= 1997-Mar-30.9378482755
Comet physical (GM= km^3/s^2; RAD= km):
GM= n.a. RAD= 30.
M1= 4. M2= n.a. k1= 8. k2= n.a. PHCOF= n.a.
COMET comments
1: soln ref.= JPL#J971B/1, data arc: 2005-02-18 to 2013-08-13
2: k1=8.;Not valid before 2005-1-1
Results
*******************************************************************************
Ephemeris / WWW_USER Sun Apr 18 15:55:44 2021 Pasadena, USA / Horizons
*******************************************************************************
Target body name: Hale-Bopp (C/1995 O1) {source: JPL#J971B/1}
Center body name: Earth (399) {source: DE441}
Center-site name: Trieste
*******************************************************************************
Start time : A.D. 1997-Mar-15 19:00:00.0000 UT
Stop time : A.D. 1997-Apr-15 00:00:00.0000 UT
Step-size : 1440 minutes
*******************************************************************************
Target pole/equ : No model available
Target radii : 30.0 km
Center geodetic : 13.7704000,45.6432920,0.0627321 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 13.7704000,4466.79794,4537.6625 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : High-precision EOP model {East-longitude positive}
Center radii : 6378.1 x 6378.1 x 6356.8 km {Equator, meridian, pole}
Target primary : Sun
Vis. interferer : MOON (R_eq= 1737.400) km {source: DE441}
Rel. light bend : Sun, EARTH {source: DE441}
Rel. lght bnd GM: 1.3271E+11, 3.9860E+05 km^3/s^2
Small-body perts: Yes {source: SB441-N16}
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : CAL
EOP file : eop.210416.p210708
EOP coverage : DATA-BASED 1962-JAN-20 TO 2021-APR-16. PREDICTS-> 2021-JUL-07
Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass (>38.000=NO), Daylight (NO )
Table cut-offs 2: Solar elongation ( 0.0,180.0=NO ),Local Hour Angle( 0.0=NO )
Table cut-offs 3: RA/DEC angular rate ( 0.0=NO )
*******************************************************************************
Initial IAU76/J2000 heliocentric ecliptic osculating elements (au, days, deg.):
EPOCH= 2454724.5 ! 2008-Sep-15.0000000 (TDB) RMSW= n.a.
EC= .9949607008417696 QR= .9174143409263262 TP= 2450538.4378482755
OM= 282.9487539423989 W= 130.662020526416 IN= 89.21708989130315
Equivalent ICRF heliocentric cartesian coordinates (au, au/d):
X= 1.777310651684692E+00 Y= 1.638390146882499E+00 Z=-2.712743223115972E+01
VX= 4.707733989601807E-04 VY=-5.688697324931184E-04 VZ=-4.422633506770205E-03
Comet physical (GM= km^3/s^2; RAD= km):
GM= n.a. RAD= 30.
M1= 4. M2= n.a. k1= 8. k2= n.a. PHCOF= n.a.
****************************************************************************************************************
Date__(UT)__HR:MN R.A._____(ICRF)_____DEC T-mag N-mag delta deldot S-O-T /r S-T-O
****************************************************************************************************************
$$SOE
1997-Mar-15 19:00 m 23 09 15.31 +43 23 35.1 4.482 n.a. 1.33336896677886 -9.1756918 45.8885 /L 48.0901
1997-Mar-16 19:00 m 23 18 26.12 +43 52 04.1 4.454 n.a. 1.32834952974604 -7.8131005 45.7776 /L 48.3385
1997-Mar-17 19:00 m 23 27 49.30 +44 17 50.9 4.429 n.a. 1.32412191124718 -6.4313980 45.6526 /L 48.5549
1997-Mar-18 19:00 m 23 37 23.67 +44 40 44.5 4.407 n.a. 1.32069601533149 -5.0343323 45.5139 /L 48.7379
1997-Mar-19 19:00 m 23 47 07.84 +45 00 35.2 4.386 n.a. 1.31807953181004 -3.6258253 45.3617 /L 48.8864
1997-Mar-20 19:00 m 23 57 00.25 +45 17 14.4 4.369 n.a. 1.31627784629682 -2.2099369 45.1967 /L 48.9993
1997-Mar-21 19:00 m 00 06 59.17 +45 30 35.0 4.353 n.a. 1.31529397166731 -0.7908267 45.0190 /T 49.0758
1997-Mar-22 19:00 Am 00 17 02.74 +45 40 31.6 4.340 n.a. 1.31512850234985 0.6272866 44.8293 /T 49.1151
1997-Mar-23 19:00 Am 00 27 08.99 +45 47 00.6 4.330 n.a. 1.31577959252735 2.0401674 44.6280 /T 49.1169
1997-Mar-24 19:00 Am 00 37 15.91 +45 50 00.3 4.322 n.a. 1.31724295890021 3.4436062 44.4154 /T 49.0807
1997-Mar-25 19:00 Am 00 47 21.46 +45 49 30.8 4.317 n.a. 1.31951190817108 4.8334619 44.1920 /T 49.0063
1997-Mar-26 19:00 A 00 57 23.62 +45 45 34.3 4.314 n.a. 1.32257738887060 6.2057038 43.9582 /T 48.8939
1997-Mar-27 19:00 A 01 07 20.44 +45 38 14.6 4.314 n.a. 1.32642806656045 7.5564508 43.7144 /T 48.7437
1997-Mar-28 19:00 A 01 17 10.09 +45 27 37.4 4.317 n.a. 1.33105042085826 8.8820073 43.4611 /T 48.5561
1997-Mar-29 19:00 A 01 26 50.88 +45 13 50.0 4.322 n.a. 1.33642886220222 10.1788957 43.1986 /T 48.3316
1997-Mar-30 19:00 A 01 36 21.26 +44 57 00.8 4.329 n.a. 1.34254586591689 11.4438843 42.9273 /T 48.0711
1997-Mar-31 19:00 A 01 45 39.91 +44 37 19.6 4.339 n.a. 1.34938212108405 12.6740104 42.6476 /T 47.7756
1997-Apr-01 19:00 A 01 54 45.66 +44 14 57.0 4.351 n.a. 1.35691669204433 13.8666014 42.3598 /T 47.4462
1997-Apr-02 19:00 A 02 03 37.59 +43 50 04.3 4.366 n.a. 1.36512719102673 15.0192928 42.0641 /T 47.0840
1997-Apr-03 19:00 A 02 12 14.94 +43 22 53.1 4.383 n.a. 1.37398996114974 16.1300458 41.7611 /T 46.6905
1997-Apr-04 19:00 A 02 20 37.17 +42 53 35.4 4.402 n.a. 1.38348026927628 17.1971638 41.4509 /T 46.2672
1997-Apr-05 19:00 A 02 28 43.90 +42 22 23.2 4.423 n.a. 1.39357250719278 18.2193041 41.1338 /T 45.8157
1997-Apr-06 19:00 A 02 36 34.92 +41 49 28.3 4.447 n.a. 1.40424039701382 19.1954799 40.8103 /T 45.3376
1997-Apr-07 19:00 A 02 44 10.17 +41 15 02.3 4.472 n.a. 1.41545719349510 20.1250468 40.4805 /T 44.8347
1997-Apr-08 19:00 Am 02 51 29.73 +40 39 16.3 4.500 n.a. 1.42719587417116 21.0076747 40.1447 /T 44.3087
1997-Apr-09 19:00 Am 02 58 33.76 +40 02 20.9 4.529 n.a. 1.43942930972174 21.8433089 39.8033 /T 43.7615
1997-Apr-10 19:00 Am 03 05 22.54 +39 24 26.2 4.560 n.a. 1.45213041133030 22.6321307 39.4565 /T 43.1949
1997-Apr-11 19:00 Am 03 11 56.42 +38 45 41.7 4.592 n.a. 1.46527225653602 23.3745231 39.1045 /T 42.6107
1997-Apr-12 19:00 Am 03 18 15.80 +38 06 16.1 4.626 n.a. 1.47882819777432 24.0710450 38.7477 /T 42.0108
1997-Apr-13 19:00 Am 03 24 21.13 +37 26 17.7 4.662 n.a. 1.49277195789724 24.7224116 38.3864 /T 41.3968
1997-Apr-14 19:00 Am 03 30 12.91 +36 45 53.9 4.699 n.a. 1.50707771553501 25.3294781 38.0208 /T 40.7706
$$EOE
****************************************************************************************************************
Column meaning:
TIME
Times PRIOR to 1962 are UT1, a mean-solar time closely related to the
prior but now-deprecated GMT. Times AFTER 1962 are in UTC, the current
civil or "wall-clock" time-scale. UTC is kept within 0.9 seconds of UT1
using integer leap-seconds for 1972 and later years.
Conversion from the internal Barycentric Dynamical Time (TDB) of solar
system dynamics to the non-uniform civil UT time-scale requested for output
has not been determined for UTC times after the next July or January 1st.
Therefore, the last known leap-second is used as a constant over future
intervals.
Time tags refer to the UT time-scale conversion from TDB on Earth
regardless of observer location within the solar system, although clock
rates may differ due to the local gravity field and no analog to "UT"
may be defined for that location.
Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank
(" ") denotes an A.D. date. Calendar dates prior to 1582-Oct-15 are in the
Julian calendar system. Later calendar dates are in the Gregorian system.
NOTE: "n.a." in output means quantity "not available" at the print-time.
SOLAR PRESENCE (OBSERVING SITE)
Time tag is followed by a blank, then a solar-presence symbol:
'*' Daylight (refracted solar upper-limb on or above apparent horizon)
'C' Civil twilight/dawn
'N' Nautical twilight/dawn
'A' Astronomical twilight/dawn
' ' Night OR geocentric ephemeris
LUNAR PRESENCE (OBSERVING SITE)
The solar-presence symbol is immediately followed by a lunar-presence symbol:
'm' Refracted upper-limb of Moon on or above apparent horizon
' ' Refracted upper-limb of Moon below apparent horizon OR geocentric
ephemeris
'R.A._____(ICRF)_____DEC' =
Astrometric right ascension and declination of the target center with
respect to the observing site (coordinate origin) in the reference frame of
the planetary ephemeris (ICRF). Compensated for down-leg light-time delay
aberration.
Units: RA in hours-minutes-seconds of time, HH MM SS.ff{ffff}
DEC in degrees-minutes-seconds of arc, sDD MN SC.f{ffff}
'T-mag N-mag' =
Comets' apparent visual total magnitude ("T-mag") and nuclear magnitude
("N-mag") using the standard IAU model:
T-mag= M1 + 5*log10(delta) + k1*log10(r)
N-mag= M2 + 5*log10(delta) + k2*log10(r) + phcof*beta
Units: MAGNITUDES
'delta deldot' =
Apparent range ("delta", light-time aberrated) and range-rate ("delta-dot")
of the target center relative to the observer. A positive "deldot" means the
target center is moving away from the observer, negative indicates movement
toward the observer. Units: AU and KM/S
'S-O-T /r' =
Sun-Observer-Target apparent SOLAR ELONGATION ANGLE seen from the observers'
location at print-time.
The '/r' column provides a code indicating the targets' apparent position
relative to the Sun in the observers' sky, as described below:
Case A: For an observing location on the surface of a rotating body, that
body rotational sense is considered:
/T indicates target TRAILS Sun (evening sky: rises and sets AFTER Sun)
/L indicates target LEADS Sun (morning sky: rises and sets BEFORE Sun)
Case B: For an observing point that does not have a rotational model (such
as a spacecraft), the "leading" and "trailing" condition is defined by the
observers' heliocentric ORBITAL motion:
* If continuing in the observers' current direction of heliocentric
motion would encounter the targets' apparent longitude first, followed
by the Sun's, the target LEADS the Sun as seen by the observer.
* If the Sun's apparent longitude would be encountered first, followed
by the targets', the target TRAILS the Sun.
Two other codes can be output:
/* indicates observer is Sun-centered (undefined)
/? Target is aligned with Sun center (no lead or trail)
The S-O-T solar elongation angle is numerically the minimum separation
angle of the Sun and target in the sky in any direction. It does NOT indicate
the amount of separation in the leading or trailing directions, which would
be defined along the equator of a spherical coordinate system.
Units: DEGREES
'S-T-O' =
The Sun-Target-Observer angle; the interior vertex angle at target center
formed by a vector from the target to the apparent center of the Sun (at
reflection time on the target) and the apparent vector from target to the
observer at print-time. Slightly different from true PHASE ANGLE (requestable
separately) at the few arcsecond level in that it includes stellar aberration
on the down-leg from target to observer. Units: DEGREES
Computations by ...
Solar System Dynamics Group, Horizons On-Line Ephemeris System
4800 Oak Grove Drive, Jet Propulsion Laboratory
Pasadena, CA 91109 USA
Information : https://ssd.jpl.nasa.gov/
Documentation: https://ssd.jpl.nasa.gov/?horizons_doc
Connect : https://ssd.jpl.nasa.gov/?horizons (browser)
telnet ssd.jpl.nasa.gov 6775 (command-line)
e-mail command interface available
Script and CGI interfaces available
Author : Jon.D.Giorgini@jpl.nasa.gov
****************************************************************************************************************
ABOUT SSD CREDITS/AWARDS PRIVACY/COPYRIGHT GLOSSARY LINKS
FirstGov 2021-Apr-18 22:55 UT
(server date/time) NASA Home Page
Site Manager: Ryan S. Park
Webmaster: Alan B. Chamberlin
|
|
|
You cannot compute a position for 1997 with the elements for 2019 (show at the ref: line). The elements are right if you compute the position for today. You must load the elements for 1997, eventually using the Add tab if you not find a file with the right format for this date. |
|
|
I take more time to look at the issue. The difference with Stellarium is because it provided the old 1997 elements with the program. This make the position right at this date but give a wrong position for today. I can generate the old 1997 elements using this page : https://minorplanetcenter.net/iau/MPEph/MPEph.html I attach the result file halebopp1997.txt here so you can get it more easily. To load the file in CdC, open the menu Setup / Solar system / Comet / Load MPC file / Or use a local file Click the file selection button, in the file filter select "All files", open the file halebopp1997.txt Click the button "Load file" Then set the location and a date in 1997, the position is now right and there is no warning message, see screen shot. halebopp1997.txt (128 bytes)
CJ95O010 1997 04 01.1373 0.914141 0.995064 130.5888 282.4707 89.4301 19970313 -2.0 4.0 C/1995 O1 (Hale-Bopp) |
|
|
Many thanks, Patrick! |
|
|
Guillermo, To help with this problem I add to the CdC distribution a file with near opposition elements for 46 old comet of interest starting with West in 1975. This file is always added to the database, so the program use the right elements when one search for an old comet at an old date. https://github.com/pchev/skychart/commit/5be82d1ddc79ae78af443c259af4bb87b406effa This will be in the next beta version. After installing it just use the menu Update / Comet elements to automatically load this file. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 21-04-19 02:37 | Guillermo Abramson | New Issue | |
| 21-04-19 02:37 | Guillermo Abramson | File Added: Cartes vs JPL.jpg | |
| 21-04-19 02:37 | Guillermo Abramson | File Added: Stellarium vs JPL.jpg | |
| 21-04-19 02:37 | Guillermo Abramson | File Added: ephemerids.txt | |
| 21-04-19 08:25 | Patrick Chevalley | Note Added: 0007025 | |
| 21-04-19 13:47 | Patrick Chevalley | Note Added: 0007026 | |
| 21-04-19 13:47 | Patrick Chevalley | File Added: halebopp1997.txt | |
| 21-04-19 13:47 | Patrick Chevalley | File Added: HB1997.png | |
| 21-04-19 14:04 | Guillermo Abramson | Note Added: 0007028 | |
| 21-04-20 11:55 | Patrick Chevalley | Assigned To | => Patrick Chevalley |
| 21-04-20 11:55 | Patrick Chevalley | Status | new => resolved |
| 21-04-20 11:55 | Patrick Chevalley | Resolution | open => fixed |
| 21-04-20 11:55 | Patrick Chevalley | Fixed in Version | => 4.3 beta |
| 21-04-20 11:55 | Patrick Chevalley | Target Version | => 4.4 |
| 21-04-20 11:55 | Patrick Chevalley | Note Added: 0007032 |
