This directory includes hourly heliocentric coordinate data for the \nHelios 1 spacecraft as extracted into the ASCII files HE1TRJyy.asc (yy \nis the two-digit year) from the merged solar wind magnetic and plasma \ndata set in HELIOS_1/MGD_FREEMAN. All trajectory parameters except solar \necliptic and heliographic inertial coordinates were taken from the \noriginal merged dataset. The other parameters were computed and added \nusing the code HELTRJCON in the MGD_FREEMAN directory. Source routines \nfor coordinate conversions in this code were provided by R. Parthasarathy\nof the Satellite Situation Center at NSSDC. The code READHEL in \nMGD_FREEMAN was used to read the archived datasets into an intermediate \nformat for input to HELTRJCON. Code HELTRJCN1 was used to correct the \nsolar ecliptic angles as of 6/14/94 (see Note 2 above). HELTRJCON was \nalso corrected as of this date.\n\nData Parameter Description:\n\nNY - YEAR OF THE DATA INTERVAL (LAST TWO DIGITS ONLY). \nND - DAY OF THE DATA INTERVAL FROM THE FIRST DAY OF THE ABOVE YEAR, \n JAN. 1= DAY 1. \nNH - HOUR OF THE DAY OF THE DATA INTERVAL. \nNCARROT - CARRINGTON ROTATION NUMBER AS SEEN BY AN EARTH BASED OBSERVER \n AT THE START OF THE DATA INTERVAL. \nSPAU - SPACECRAFT HELIOCENTRIC DISTANCE IN ASTRONOMICAL UNITS. \nSECLAT - SOLAR ECLIPTIC LATITUDE IN DEGREES\nSECLON - SOLAR ECLIPTIC LONGITUDE IN DEGREES\nHELLAT - SOLAR HELIOGRAPHIC LATITUDE IN DEGREES\nHELLON - SOLAR HELIOGRAPHIC (CARRINGTON) LONGITUDE IN DEGREES\nHILLON - SOLAR HELIOGRAPHIC INERTIAL LONGITUDE IN DEGREES WITH RESPECT TO\n ASCENDING NODE OF SOLAR EQUATOR ON THE ECLIPTIC\nESSCSANG - EARTH-SUN-SPACECRAFT SEPARATION ANGLE (IN DEGREES, 0-360). \nICODE - DATA CODE: 1 MEANS PLASMA DATA ONLY ARE PRESENT FOR THAT HOURLY \n INTERVAL; 2 MEANS MAGNETOMETER DATA ONLY; 3 MEANS BOTH PLASMA \n AND MAGNETOMETER DATA PRESENT. \n\nNote 1: The solar ecliptic coordinates are given with respect to true\nequinox and ecliptic of date. The solar ascending node was located at\necliptic longitude +74.367 degrees as of 1 Jan. 1900 at 1200 UT; this\nlongitude increases by 1.4 degrees/century.\n\nNote 2: The solar ecliptic cordinates in this directory before 6/14/94 were\ncalculated incorrectly and have been corrected as of this date. The\nheliographic angles are from the original source dataset and had no problems.\n\n