Hej igen!
Jag gjorde en beräkning här för de kommande 10 dagarna, alltså data för att styra monteringen så den följer kometen. Beräknat sett från Stockholm, men platsen lär inte på verka dessa data.
Det är dRA*cosD och d(DEC)/dt du skall använda dig av. De är i bågsekunder per timme. Antagligen får du räkna om det till per minut eller sekund. Jag har inte kontrollerat om jag matat in det här rätt, men någon annan kanske ser om positionen av kometen blev rätt så jag inte blandat ihop det som det brukar bli när man skall göra något snabbt.
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JPL/HORIZONS Lovejoy (C/2014 Q2) 2015-Jan-11 05:31:23
Rec #:904040 (+COV) Soln.date: 2015-Jan-07_23:42:01 # obs: 1281 (2014-2015)
FK5/J2000.0 helio. ecliptic osc. elements (au, days, deg., period=Julian yrs):
EPOCH= 2456981.5 != 2014-Nov-20.0000000 (CT) RMSW= n.a.
EC= .9977694972445712 QR= 1.290354613349346 TP= 2457052.5702290521
OM= 94.97534212651479 W= 12.39562582691785 IN= 80.30301629940526
A= 578.5039315503041 MA= 359.99496577854 ADIST= 1155.717508487259
PER= 13914.50260831 N= 7.083400000000001E-5 ANGMOM= .027619046
DAN= 1.30555 DDN= 101.13171 L= 97.0954577
B= 12.2157673 MOID= .31962699 TP= 2015-Jan-30.0702290521
Comet physical (GM= km^3/s^2; RAD= km):
GM= n.a. RAD= n.a.
M1= 7.4 M2= 12.2 k1= 14. k2= 5. PHCOF= .030
COMET comments
1: soln ref.= JPL#18, data arc: 2014-07-01 to 2015-01-02
2: k1=14., k2=5., phase coef.=0.03;
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Ephemeris / WWW_USER Sun Jan 11 05:31:23 2015 Pasadena, USA / Horizons
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Target body name: Lovejoy (C/2014 Q2) {source: JPL#18}
Center body name: Earth (399) {source: DE-0431LE-0431}
Center-site name: (user defined site below)
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Start time : A.D. 2015-Jan-12 00:00:00.0000 UT
Stop time : A.D. 2015-Jan-25 00:00:00.0000 UT
Step-size : 1440 minutes
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Target pole/equ : No model available
Target radii : (unavailable)
Center geodetic : 18.0000000,59.3833000,-8.09E-13 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 18.0000000,3256.41859,5465.8052 {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
Vis. interferer : MOON (R_eq= 1737.400) km {source: DE-0431LE-0431}
Rel. light bend : Sun, EARTH {source: DE-0431LE-0431}
Rel. lght bnd GM: 1.3271E+11, 3.9860E+05 km^3/s^2
Small-body perts: Yes {source: SB431-BIG16}
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : CAL
EOP file : eop.150109.p150402
EOP coverage : DATA-BASED 1962-JAN-20 TO 2015-JAN-09. PREDICTS-> 2015-APR-01
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 )
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Initial FK5/J2000.0 heliocentric ecliptic osculating elements (au, days, deg.):
EPOCH= 2456981.5 != 2014-Nov-20.0000000 (CT) RMSW= n.a.
EC= .9977694972445712 QR= 1.290354613349346 TP= 2457052.5702290521
OM= 94.97534212651479 W= 12.39562582691785 IN= 80.30301629940526
Comet physical (GM= km^3/s^2; RAD= km):
GM= n.a. RAD= n.a.
M1= 7.4 M2= 12.2 k1= 14. k2= 5. PHCOF= .030
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Date__(UT)__HR:MN R.A._(ICRF/J2000.0)_DEC dRA*cosD d(DEC)/dt T-mag N-mag S-T-O
****************************************************************************************
$$SOE
2015-Jan-12 00:00 m 03 48 48.35 +07 27 30.9 -232.736 360.4355 4.33 n.a. 37.9135
2015-Jan-13 00:00 m 03 42 38.09 +09 49 44.7 -225.230 350.3535 4.34 n.a. 38.8645
2015-Jan-14 00:00 03 36 37.71 +12 07 40.8 -217.229 338.8154 4.35 n.a. 39.8259
2015-Jan-15 00:00 03 30 47.60 +14 20 48.2 -208.867 326.1691 4.37 n.a. 40.7808
2015-Jan-16 00:00 03 25 08.03 +16 28 44.4 -200.266 312.7490 4.40 n.a. 41.7148
2015-Jan-17 00:00 03 19 39.20 +18 31 14.2 -191.541 298.8624 4.43 n.a. 42.6160
2015-Jan-18 00:00 03 14 21.23 +20 28 09.6 -182.793 284.7803 4.47 n.a. 43.4747
2015-Jan-19 00:00 03 09 14.17 +22 19 28.6 -174.107 270.7330 4.50 n.a. 44.2836
2015-Jan-20 00:00 03 04 18.01 +24 05 14.1 -165.558 256.9087 4.54 n.a. 45.0377
2015-Jan-21 00:00 02 59 32.68 +25 45 33.2 -157.203 243.4555 4.59 n.a. 45.7334
2015-Jan-22 00:00 02 54 58.04 +27 20 35.9 -149.092 230.4847 4.63 n.a. 46.3688
2015-Jan-23 00:00 02 50 33.94 +28 50 34.7 -141.258 218.0750 4.68 n.a. 46.9435
2015-Jan-24 00:00 02 46 20.15 +30 15 43.5 -133.727 206.2776 4.73 n.a. 47.4576
2015-Jan-25 00:00 02 42 16.44 +31 36 17.2 -126.516 195.1211 4.78 n.a. 47.9124
$$EOE
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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.
Time tags refer to the same instant throughout the universe, regardless of
where the observer is located.
The dynamical Coordinate Time scale is used internally. It is equivalent to
the current IAU definition of "TDB". 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 (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/J2000.0)_DEC =
J2000.0 astrometric right ascension and declination of target center.
Adjusted for light-time. Units: HMS (HH MM SS.ff) and DMS (DD MM SS.f)
dRA*cosD d(DEC)/dt =
The rate of change of target center apparent RA and DEC (airless).
d(RA)/dt is multiplied by the cosine of the declination.
Units: ARCSECONDS PER HOUR
T-mag =
SPECIAL CASE: Comet C/2014 Q2 (Lovejoy) approximate apparent visual
total magnitude ("T-mag") from following non-standard definition [Yoshida]:
MT = 3.5 + 5*log10(rho) + 20.0*log10(r)
Units: MAGNITUDES
S-T-O =
"S-T-O" is the Sun->Target->Observer angle; the interior vertex angle at
target center formed by a vector to the apparent center of the Sun at
reflection time on the target and the apparent vector 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:
http://ssd.jpl.nasa.gov/
Connect : telnet://ssd.jpl.nasa.gov:6775 (via browser)
telnet ssd.jpl.nasa.gov 6775 (via command-line)
Author :
Jon.Giorgini@jpl.nasa.gov
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/Lars
