10 
2.2 Levels, standards and constants 
The results of this edition refer to the International Magnetic Standard (IMS). The results of the 
yearbooks up to and including 1980 referred to the Observatory Standard (OBS), which was 
represented by the classic type base line instruments bound to their original locations and surround 
ings. 
H, Z, and Fare referred to the proton vector magnetometer (PVM) of type 
ASKANIA/V4931 (VARIAN) on pier NW (section 3.2), Dto the fluxgate theodolite (Dl-flux) of type 
010B(ZEISS)/MAG01 H(BARTINGTON) on pier NE (section 3.1) of the absolute house. Both 
instruments are assumed to represent IMS. 
The following equations apply to D (see yearbook No 37, 1991), H and Z (see yearbook No 38, 
1992): 
D 0 
H„ 
- W IMS + 6 - 7 nT 
— ^ims + 1 T1 nT. 
The differences for the derived elements depend on the components, i.e. from 1996 to 1999: 
'obs 'ims 1 
"^OBS — ^IMS + 6.7 nT 
Y - Y 
OBS IMS 
The following physical standards are available at Wingst. They guarantee the quality of data: 
SCHWILLE (frequency, DCF77, 10' 8 ) 
PATEK PHILIPPE and HOPF (UTC, DCF77) 
CROPICO VS10 (Voltage, 51 O'*) 
GUILDLINE 100 Ohm (resistance, 5'10*) 
Helmholtz coil of high precision (magnetic field strength, 10' 4 ) 
For the determination of the magnetic induction, the lAGA-recommended gyromagnetic constant 
(Rasmussen, 1991) was used: 
2tit' 1 = 23.487203 nT s 
The azimuth marks were last checked by the German Geodetic Survey in 1995. There values, 
related to the NE pier (R: 3504926.873, H: 5956702.028), are: 
Azimuth mark 
Azimuth 
N 
11° 38.36’ 
NE 
13° 23.19’ 
W 
308° 42.94’