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- From: dave@eram.esi.COM.AU (Dave Horsfall)
- Newsgroups: aus.radio.amsat
- Subject: SIDEREAL ANGLES FOR W3IWI PROGRAM
- Message-ID: <2540@eram.esi.COM.AU>
- Date: 21 Dec 92 00:26:54 GMT
- Distribution: aus
- Organization: Pacific ESI, Sydney, AUSTRALIA
- Lines: 69
-
- HR AMSAT NEWS SERVICE BULLETIN 354.03 FROM AMSAT HQ
- SILVER SPRING, MD DECEMBER 19, 1992 BID: $ANS-354.03
- TO ALL RADIO AMATEURS BT
-
- G3RUH Provides Sidereal Angles Needed For The W3IWI Tracking Program
-
- AMSAT-OSCAR-13 (AO-13) Ground Station operator, James Miller (G3RUH), is
- aware that there are a great number of hams who currently are using the
- orginal "IWI" satellite program written by Tom Clark (W3IWI). One of the
- important input parameters needed to run Tom's program is the "sidereal"
- angle or the "G2" constant inside the progam. It is necessary for one to
- update it at the beginning of each year. The following is the listing of
- this short BASIC computer program which generated the table.
-
- LIST
-
- T$="B.GHAA(0)": REM GMST of 0000 utc Calculator. Based on
- REM 1984 Astronomical Almanac Pages B6 & S13.
- REM
- REM Version 1.1 Last modified 1985 May 08 by JRM
- REM
- REM (C)1991 J R Miller G3RUH
- REM
- REM GMST =24110.54841 + TU*(8640184.812866+TU*(0.093104+TU*(-6.2E-6)))
- REM (seconds).
- REM
- REM where Tu is the interval of time, (measured in Julian centuries
- REM of 36525 days of universal time), elapsed since the epoch
- REM 2000 Jan 1.5 i.e TU = (JD - 2451545.0)/36525
- REM
- FI%=&80F: FF%=&2060F: REM Print formats; ######### #.######
- :
- PRINT"Program ";T$;" GHAA for Year yyyy Jan 0.0 (C)1991 G3RUH"
- PRINT
- PRINT" YEAR GHAA deg GMST rev"
- PRINT" -------------------------------------"
- FOR YR = 1988 TO 2000
- DD = FND0(YR)-(FND0(2000)+1.5): REM Days since 2000 Jan 1.5
- TU = DD/36525
- G1 = TU*(184.812866+TU*(0.093104+TU*(-6.2E-6)))/86400 :REM Small part
- G2 = TU*100 :REM Big part
- G3 = 0.2790572733 :REM 24110.54841/86400
- GMST = G1+G2+G3: GMST=GMST-INT(GMST): GHAA=GMST*360
- @%=FI%: PRINT YR;: @%=FF%: PRINT GHAA,GMST
- NEXT
- STOP
- DEF FND0(YR)=INT((YR-1)*365.25)
-
- RUN
-
- Program B.GHAA(0) GHAA for Year yyyy Jan 0.0 (C)1991 G3RUH
-
- YEAR GHAA deg GMST rev
- -------------------------------------
- 1993 99.667481 0.276854
- 1994 99.428769 0.276191
- 1995 99.190057 0.275528
- 1996 98.951346 0.274865
- 1997 99.698282 0.276940
- 1998 99.459570 0.276277
- 1999 99.220859 0.275613
- 2000 98.982147 0.274950
-
- [The AMSAT News Service (ANS) would like James Miller (G3RUH) for this
- bulletin item.]
-
- --
- Dave Horsfall (VK2KFU) VK2KFU @ VK2RWI.NSW.AUS.OC
- dave@esi.COM.AU ...munnari!esi.COM.AU!dave
-