# [amsat-bb] Re: Planet Pseudo-Keps

Joe Fitzgerald jfitzgerald at alum.wpi.edu
Sat Feb 27 10:35:44 PST 2010

Auke de Jong, VE6PWN wrote:
>
> On second thought, the software that runs the fully-automated personal
> telescopes already does most of this, except for the relative velocity part.
>
>
The US government will do that for us via the JPL HORIZONS tracking
system http://ssd.jpl.nasa.gov/?horizons  The data below show that as
this being written I should point my antennas to the south, a little
less than half way up from horizon to my zenith.  Jupiter is moving away
from me at about  six and a half kilometers per second, and a "dit"
leaving my keyer will take the better part of an hour to reach it's target.

No charge to use this, US hams pay for this with our taxes.  That being
to pay the appropriate US income tax on it!

-Joe KM1P

*******************************************************************************
Revised: Dec 17, 2009              Jupiter                                 599

PHYSICAL DATA (updated 2009-Jan-28):
Mass (10^24 kg)       =  1898.13+-.19   Density (g/cm^3)       =  1.326
Equat. radius (1 bar) = 71492+-4 km     Polar radius (km)      = 66854+-10
Volumetric mean radius= 69911+-6 km     Flattening             =  0.06487

Rotation period       = 9h 55m 29.685s  Rot. rate(10^-4 rad/s) =  1.75865
m = w^2a^3/GM         =  0.089195       Hydrostatic flat., fh  =  0.06509
Inferred rot. period  =  9.894+-0.02 hr ks = 3*J2/m            =  0.494
Mom. of inert. I/MRo^2=  0.254          I/MRo^2 (upper bound)  =  0.267
Rocky core mass (Mc/M)=  0.0261         Y factor (He/H ratio)  =  0.18+-0.04

GM (km^3/s^2)         = 126,686,511     GM 1-sigma (km^3/s^2)  = +-100
Equ. grav, ge (m/s^2) = 24.79           Pol. grav, gp (m/s^2)  = 28.34

Geometric albedo      =  0.52           Visual magnitude V(1,0)= -9.40
Vis. mag. (opposition)= -2.70           Obliquity to orbit     =  3.12 deg
Sidereal orbit period = 11.862615 yr    Sidereal orbit period  = 4332.820 d
Mean daily motion     = 0.0831294 deg/d Mean orbit velocity    = 13.0697 km/s

Atmos. temp. (1 bar)  = 165+-5 K        Heat flow/mass (x10^7) = 15 erg/gm*s
Planetary Solar Const =  50.5 W/m^2     Dipole tilt/offset     = 9.6deg/0.1Rp
Escape velocity (km/s)=  59.5           Mag.dip.mom(gauss-Rp^3)= 4.2
Aroche(ice)/Rp        =  2.76           Hill's sphere rad. Rp  = 740
*******************************************************************************

*******************************************************************************
Ephemeris / WWW_USER Sat Feb 27 10:15:04 2010  Pasadena, USA     / Horizons
*******************************************************************************
Target body name: Jupiter (599)                   {source: JUP230}
Center body name: Earth (399)                     {source: DE405}
Center-site name: (user defined site below)
*******************************************************************************
Start time      : A.D. 2010-Feb-10 17:00:00.0000 UT
Stop  time      : A.D. 2010-Feb-10 20:00:00.0000 UT
Step-size       : 5 minutes
*******************************************************************************
Target pole/equ : IAU_JUPITER                     {East-longitude -}
Target radii    : 71492.0 x 71492.0 x 66854.0 km  {Equator, meridian, pole}
Center geodetic : 288.845300,42.2925472,49.999402 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 288.845300,4762.18349,4303.3386 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : High-precision EOP model        {East-longitude +}
Center radii    : 6378.1 x 6378.1 x 6356.8 km     {Equator, meridian, pole}
Target primary  : Sun                             {source: DE405+DE408}
Interfering body: MOON (Req= 1737.400) km         {source: DE405}
Deflecting body : Sun, EARTH                      {source: DE405}
Deflecting GMs  : 1.3271E+11, 3.9860E+05 km^3/s^2
Atmos refraction: NO (AIRLESS)
RA format       : HMS
Time format     : CAL
RTS-only print  : NO
EOP file        : eop.100226.p100520
EOP coverage    : DATA-BASED 1962-JAN-20 TO 2010-FEB-26. PREDICTS-> 2010-MAY-19
Units conversion: 1 AU= 149597870.691 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 )
*****************************************************************************************************************
Date__(UT)__HR:MN     Azi_(a-appr)_Elev dAZ*cosE d(ELV)/dt  APmag  S-brt            delta      deldot   1-way_LT
*****************************************************************************************************************
\$\$SOE
2010-Feb-10 17:00 *m  163.9922  35.9868   867.85    184.19  -2.02   5.31 8.8974883901E+08   6.3227121  49.464711
2010-Feb-10 17:05 *m  165.4872  36.2310   871.25    167.40  -2.02   5.31 8.8975073674E+08   6.3287606  49.464817
2010-Feb-10 17:10 *m  166.9922  36.4517   874.35    150.38  -2.02   5.31 8.8975263628E+08   6.3348429  49.464922
2010-Feb-10 17:15 *m  168.5063  36.6486   877.14    133.15  -2.02   5.31 8.8975453766E+08   6.3409553  49.465028
2010-Feb-10 17:20 *m  170.0287  36.8215   879.61    115.74  -2.02   5.31 8.8975644087E+08   6.3470944  49.465134
2010-Feb-10 17:25 *m  171.5582  36.9700   881.74     98.16  -2.02   5.30 8.8975834593E+08   6.3532567  49.465240
2010-Feb-10 17:30 *m  173.0940  37.0941   883.54     80.44  -2.02   5.30 8.8976025284E+08   6.3594385  49.465346
2010-Feb-10 17:35 *m  174.6348  37.1934   884.98     62.60  -2.02   5.30 8.8976216161E+08   6.3656364  49.465452
2010-Feb-10 17:40 *m  176.1796  37.2679   886.07     44.67  -2.02   5.29 8.8976407224E+08   6.3718469  49.465558
2010-Feb-10 17:45 *m  177.7272  37.3175   886.79     26.68  -2.02   5.29 8.8976598473E+08   6.3780662  49.465664
2010-Feb-10 17:50 *m  179.2766  37.3420   887.15      8.64  -2.02   5.29 8.8976789909E+08   6.3842910  49.465771
2010-Feb-10 17:55 *t  180.8265  37.3415   887.15     -9.40  -2.02   5.28 8.8976981532E+08   6.3905176  49.465877
2010-Feb-10 18:00 *m  182.3758  37.3159   886.77    -27.44  -2.02   5.28 8.8977173341E+08   6.3967424  49.465984
2010-Feb-10 18:05 *m  183.9233  37.2653   886.03    -45.43  -2.02   5.27 8.8977365338E+08   6.4029620  49.466091
2010-Feb-10 18:10 *m  185.4680  37.1897   884.93    -63.36  -2.02   5.27 8.8977557520E+08   6.4091726  49.466197
2010-Feb-10 18:15 *m  187.0086  37.0893   883.48    -81.19  -2.02   5.27 8.8977749889E+08   6.4153709  49.466304
2010-Feb-10 18:20 *m  188.5441  36.9643   881.67    -98.90  -2.02   5.26 8.8977942444E+08   6.4215531  49.466411
2010-Feb-10 18:25 *m  190.0734  36.8147   879.52   -116.48  -2.02   5.26 8.8978135184E+08   6.4277158  49.466519
2010-Feb-10 18:30 *m  191.5955  36.6408   877.04   -133.88  -2.02   5.26 8.8978328108E+08   6.4338554  49.466626
2010-Feb-10 18:35 *m  193.1093  36.4429   874.24   -151.10  -2.02   5.25 8.8978521216E+08   6.4399685  49.466733
2010-Feb-10 18:40 *m  194.6139  36.2212   871.13   -168.11  -2.02   5.25 8.8978714507E+08   6.4460514  49.466841
2010-Feb-10 18:45 *m  196.1085  35.9760   867.72   -184.89  -2.02   5.25 8.8978907980E+08   6.4521008  49.466948
2010-Feb-10 18:50 *m  197.5921  35.7077   864.04   -201.43  -2.02   5.25 8.8979101634E+08   6.4581130  49.467056
2010-Feb-10 18:55 *m  199.0640  35.4166   860.08   -217.70  -2.02   5.25 8.8979295468E+08   6.4640847  49.467164
2010-Feb-10 19:00 *m  200.5234  35.1031   855.88   -233.69  -2.02   5.24 8.8979489480E+08   6.4700124  49.467271
2010-Feb-10 19:05 *   201.9698  34.7676   851.44   -249.38  -2.02   5.24 8.8979683669E+08   6.4758927  49.467379
2010-Feb-10 19:10 *   203.4023  34.4105   846.78   -264.78  -2.02   5.24 8.8979878034E+08   6.4817222  49.467488
2010-Feb-10 19:15 *   204.8206  34.0323   841.92   -279.85  -2.02   5.24 8.8980072573E+08   6.4874975  49.467596
2010-Feb-10 19:20 *   206.2242  33.6333   836.87   -294.60  -2.02   5.24 8.8980267285E+08   6.4932152  49.467704
2010-Feb-10 19:25 *   207.6125  33.2141   831.66   -309.02  -2.02   5.25 8.8980462167E+08   6.4988721  49.467812
2010-Feb-10 19:30 *   208.9853  32.7751   826.29   -323.09  -2.02   5.25 8.8980657218E+08   6.5044648  49.467921
2010-Feb-10 19:35 *   210.3423  32.3168   820.79   -336.82  -2.02   5.25 8.8980852435E+08   6.5099901  49.468029
2010-Feb-10 19:40 *   211.6831  31.8396   815.17   -350.20  -2.02   5.25 8.8981047818E+08   6.5154447  49.468138
2010-Feb-10 19:45 *   213.0077  31.3441   809.45   -363.23  -2.02   5.25 8.8981243363E+08   6.5208255  49.468247
2010-Feb-10 19:50 *   214.3158  30.8308   803.64   -375.91  -2.02   5.26 8.8981439068E+08   6.5261292  49.468355
2010-Feb-10 19:55 *   215.6074  30.3001   797.76   -388.24  -2.02   5.26 8.8981634931E+08   6.5313528  49.468464
2010-Feb-10 20:00 *   216.8824  29.7525   791.82   -400.21  -2.02   5.26 8.8981830950E+08   6.5364932  49.468573
\$\$EOE
*****************************************************************************************************************
Column meaning:

TIME

Prior to 1962, times are UT1. Dates thereafter are UTC. 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.

The uniform Coordinate Time scale is used internally. Conversion between
CT and the selected non-uniform UT output scale has not been determined for
UTC times after the next July or January 1st.  The last known leap-second
is used over any future interval.

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 WITH TARGET RISE/TRANSIT/SET MARKER (OBSERVING SITE)
The solar-presence symbol is immediately followed by another marker symbol:

'm'  Refracted upper-limb of Moon on or above apparent horizon
' '  Refracted upper-limb of Moon below apparent horizon OR geocentric
'r'  Rise    (target body on or above cut-off RTS elevation)
't'  Transit (target body at or past local maximum RTS elevation)
's'  Set     (target body on or below cut-off RTS elevation)

RTS MARKERS (TVH)
Rise and set are with respect to the reference ellipsoid true visual horizon
defined by the elevation cut-off angle. Horizon dip and yellow-light refraction
(Earth only) are considered. Accuracy is < or = to twice the requested search
step-size.

Azi_(a-appr)_Elev =
Airless apparent azimuth and elevation of target center. Corrected for
light-time, the gravitational deflection of light, stellar aberration,
precession and nutation. Azimuth measured North(0) -> East(90) -> South(180) ->
West(270) -> North (360). Elevation is with respect to plane perpendicular
to local zenith direction.  TOPOCENTRIC ONLY. Units: DEGREES

dAZ*cosE d(ELV)/dt =
The rate of change of target center apparent azimuth and elevation
(airless). d(AZ)/dt is multiplied by the cosine of the elevation angle.
TOPOCENTRIC ONLY. Units: ARCSECOND/MINUTE

APmag S-brt =
Target's approximate apparent visual magnitude & surface brightness. For
planets and satellites, values are available only for solar phase angles in the
range generally visible from Earth. This is to avoid extrapolation of models
beyond their valid (data-based) limits.  Units: NONE & VISUAL MAGNITUDES PER
SQUARE ARCSECOND

delta  deldot =
Range ("delta") and range-rate ("delta-dot") of the target center relative
to the observer at the instant light seen by the observer at print-time would
have left the target center (print-time minus down-leg light-time); the
distance traveled by a light ray emanating from the center of the target and
recorded by the observer at print-time. "deldot" is a projection of the
velocity vector along this ray, the light-time-corrected line-of-sight from
the coordinate center, and indicates relative motion. A positive "deldot" means
the target center is moving away from the observer (coordinate center). A
negative "deldot" means the target center is moving toward the observer.
Units: KM and KM/S

1-way_LT =
1-way down-leg light-time from target center to observer. The elapsed time
since light (observed at print-time) would have left or reflected off a point
at the center of the target. Units: MINUTES

Computations by ...
Solar System Dynamics Group, Horizons On-Line Ephemeris System
4800 Oak Grove Drive, Jet Propulsion Laboratory