BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Six-second interplanetary magnetic field data files from the Ness et al. magnetometer on Helios 1 have been updated from Jan. 1979 to July 1981. These files are located at helios1/mag/6sec_ness. 03/15/2005 JFC BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Six-second interplanetary magnetic field data files from the Ness et al. magnetometer on Helios 1 have been uploaded from the NSSDC tape archive to directory helios1/mag/6sec_ness. These data in ASCII format and daily files cover various discontinuous intervals from 1974/349 through 1978/363. 04/11/2002 JFC BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! An erratum has been added to the format description file h-a-cr.txt in helios/helios1/particle/e6_kunow to advise that the last of the four data files for particle counts from the E6 instrument of Kunow et al from Kiel is missing the last two data columns per hourly frame and must be read with a modified format statement. 4/25/2001 JFC BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! This Helios 1 update file has been extracted from the old aaupdate.doc file at the VMS anonymous FTP site for all COHO-related datasets. Directory names for current Helios 1/2 data sets have been changed for new locations at this new site. Note that all directory and file names at this site are actually in lower case, even though they are given below in upper case. 2/24/99 JFC BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! The HE1MAG and HE2MAG files for Helios 1/2 magnetometer data have been renamed to avoid confusion between files from the Ness and Neubauer magnetometers, for which the new file prefixes are HE1MGA* and HE2MGB*, respectively. These files are located at directory HELIOSn/MAG for n = 1 & 2. 6/20/97 JFC BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Archived data from the Fluxgate Magnetometer for Average Fields (P.I.: N. F. Ness, Univ. of Delaware) experiments on Helios 1 and 2 have been received from F. Mariani of the Istituto di Fisica G. Marconi in Rome, Italy. These include hourly averaged ASCII data covering 1974-12-14 to 1981-06-14 for Helios 1 and 1976-01-17 to 1980-03-08 for Helios 2. These data sets are located within the HELIOS1/MAG and HELIOS2/MAG directories. Note that COHO directory reorganization is still in progress. 9/26/96 JFC BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! VAX versions of Helios 1 and 2 binary data sets in the NSSDC off-line tape archive for merged field and plasma data at hourly resolution have been copied into COHO subdirectories HELIOS1/MGD_FREEMAN and HELIOS2/MGD_FREEMAN, respectively. A sample FORTRAN read program for writing selected parameters to ASCII files is also included. This program was used previously to write the key parameter files now in subdirectories HELIOS1/TRAJ, HELIOS2/TRAJ, HELIOS1/MAG, HELIOS2/MAG, HELIOS1/PLASMA, and HELIOS2/PLASMA. The binary data files contain all parameters included in the original Helios data sets submitted to NSSDC and merged together by J. Freeman of Rice University. {warning: these VMS binary files cannot be maintained at the new UNIX site but can be found on the old VAX/VMS site at anonymous@nssdca.gsfc.nasa.gov/coho/helios1/plasma/mgd_freeman and .../coho/helios2/... , or via the Anonymous FTP (VMS) link at http://nssdc.gsfc.nasa.gov/space/ } 5/12/95 JFC BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Before this date the solar ecliptic coordinates for Helios 1 and Helios 2 in directories HELIOS1/TRAJ and HELIOS2/TRAJ have been found to be incorrect. Although the heliographic coordinates supplied with the original Helios datasets from NSSDC were correct, the solar ecliptic coordinates were not in these datasets and had to be calculated. These latter coordinates have now been recalculated and are correct. Thanks to Walter Koehnlein (Inst. for Planetary Exploration, German Aerospace Establishment, Berlin, Germany) for discovering this error in the COHO data. 06/14/94 JFC BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Although many users need heliographic spacecraft coordinates with latitudes calculated with respect to the solar equator, some may not want Carrington longitudes which are in a system fixed to the rotating Sun. Inertial longitudes are defined with respect to the ascending node of the solar equator on the Ecliptic; this node was at solar ecliptic longitude +74.367 degrees as of 1 Jan. 1900 at 1200 UT and its longitude increases by 1.4 degrees per century due to precession of the equinoxes in the solar ecliptic system. Heliographic inertial longitudes have been added to the trajectory data files in COHO for all missions except Helios 1/2 and Pioneer Venus Orbiter; these latter missions will be done later. JFC/11-16-93 Postnote: Solar ecliptic angles and heliographic inertial longitude have been added to the Helios 1 and 2 trajectory files. JFC/11-30-93 BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! The proton flow angles in the Helios 1/2 plasma data directories are incorrect and are being recopied from the source dataset. Do not use the previously provided flow angles for data analysis, since these fields actually contained standard deviations of other parameters. JFC/03-19-93 Postnote: The Helios 1/2 proton flow angles have been corrected. JFC/03-26-93 BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! There has been some confusion about the usage of the term "solar ecliptic" coordinates to describe the vector components of the Helios 1 and 2 magnetic fields in the data format files HE1MAG.FMT and HE2MAG.FMT in subdirectories HELIOS1/MAG and HELIOS2/MAG, respectively. We have checked the dataset documentation and confirmed that the correct terminology should be Spacecraft-centered Solar Ecliptic (SSE) coordinates, which are analogous to the Geocentric Solar Ecliptic (GSE) coordinates used for IMP-8 magnetic field components in the OMNI data base. The format files have been revised accordingly. J. F. Cooper 02/05/93 BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Helios 1/2 magnetic field, plasma, and trajectory data for launch through 1980 are now available in the HELIOS1 and HELIOS2 directories. J. F. Cooper 10/20/92 BULLETIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Merged ephemeris, magnetic field, and solar wind plasma data are being ingested into COHO from the Helios 1/2 archive tape. The heliocentric spacecraft coordinates are now in HELIOS1/TRAJ and HELIOS2/TRAJ for Helios 1 and 2, resp. The field and plasma data are coming soon. J. F. Cooper 9/28/92