Quote:
Originally Posted by frankuitaalst
Hi Sir ,
the ephemeris for New Horizons can be found here ..;
http://ssd.jpl.nasa.gov/horizons.cgi#top
Try to change the target body , eventually the reference body and the date , and JPL gives you the position and velocity at any desirable date
( best to do this in the past ...) |
Sir,
I checked the web site at JPL. I took the data and did following
simple calculations:
A. Distance of NH from SUN on 2009-Jan-01 00:00:00.0000 hrs =SQRT((X)^2+(Y)^2+(Z)^2) = 1803006898 KM
B. Distance of NH from SUN on 2009-Jan-02 00:00:00.0000 hrs =SQRT((X)^2+(Y)^2+(Z)^2) = 1804429053 KM
C. Distance traveled in One day = B-A = 1422154.774 KM
D. Velocity of NH on 2009-Jan-01 00:00:00.0000 hrs =SQRT((VX)^2+(VY)^2+(VZ)^2) = 17.44302161 KM/sec
E. Velocity of NH on 2009-Jan-02 00:00:00.0000 hrs =SQRT((VX)^2+(VY)^2+(VZ)^2) = 17.43967449KM/sec
Here I took both D&E are equal approximately for practical calculations purpose.
F. Distance traveled by NH in one day = Velocity x 24 x 60 x 60
= 1507077.067 KM by velocity from D ( or = 1506787.876 KM by velocity from E)
G.
CALCULATED Distance of NH from SUN as on 2009-Jan-02 00:00:00.0000 hrs = A + F from D = 1804513975 KM (or = A + F from E the lower of two = 1804513686 KM)
Hence it is obvious that calculated distance is high compared to ephemeris given by the JPL web site by 84922.29317 Km ( or by 84633.10179 km using the Lower value of velocity)
It is quite possible that I am wrong while doing my simple calculations or there is some fundamental mistake I am committing.
CAN SOME OF YOU PLEASE EXPLAIN ME, WHAT WENT WRONG…???
....
....
References:
Starting data given at [
http://ssd.jpl.nasa.gov/horizons.cgi#top] is
…….
Ephemeris Type [change]: VECTORS
Target Body [change] :
New Horizons Spacecraft [NH New_Horizons (Spacecraft)] [-98]
Coordinate Origin [change] :
Sun (body center) [500@10]
Time Span [change] :
Start=2009-01-01, Stop=2009-08-09, Step=1 d
Table Settings [change] :
output units=KM-S; labels=YES; CSV format=YES
Display/Output [change] :
default (formatted HTML)
=====
The website [
http://ssd.jpl.nasa.gov/horizons.cgi#results ] gives initial part of output as:
************************************************** *****************************
JDCT , , X, Y, Z, VX, VY, VZ, LT, RG, RR,
************************************************** *****************************
$$SOE
2454832.500000000, A.D. 2009-Jan-01 00:00:00.0000, 1.831893455702002E+07, -1.802262411312388E+09, 4.846124849130476E+07, 5.934007305388568E+00, -1.639090119518093E+01, 6.204177119092869E-01, 6.014183646564395E+03, 1.803006898266943E+09, 1.646109953796153E+01,
2454833.500000000, A.D. 2009-Jan-02 00:00:00.0000, 1.883163093861168E+07, -1.803678432152277E+09, 4.851484847298443E+07, 5.933962828747228E+00, -1.638735887443054E+01, 6.203228521582478E-01, 6.018927444267887E+03, 1.804429053040728E+09, 1.645914910252247E+01,
2454834.500000000, A.D. 2009-Jan-03 00:00:00.0000, 1.934432343887030E+07, -1.805094147191313E+09, 4.856844026294923E+07, 5.933917498126769E+00, -1.638382224826633E+01, 6.202281034865420E-01, 6.023670680165160E+03, 1.805851039389245E+09, 1.645720058391782E+01,
2454835.500000000, A.D. 2009-Jan-04 00:00:00.0000, 1.985701198286318E+07, -1.806509556919445E+09, 4.862202387102771E+07, 5.933871323030025E+00, -1.638029130241139E+01, 6.201334651586903E-01, 6.028413354803478E+03, 1.807272857476561E+09, 1.645525398005856E+01,
….
….
======
Warm regards