11 
2.3 Special measurements 
In the years under review, comparative measurements were carried out at Wingst and at the ob 
servatories Niemegk (NGK) and Fürstenfeldbruck (FUR). The station differences are as follows: 
at 
WNG minus 
D 
I 
F 
1996 FUR 
FUR 
+0.01’ 
-0.04’ 
NGK 
NGK 
-0.21 
+0.03 
-0.7nT 
WNG 
NGK 
+0.11 
-0.19 
+0.7 
1997 NGK 
NGK 
+0.34 
-0.01 
+1.4 
1998 FUR 
FUR 
+0.24 
-0.16 
-2.3 
WNG 
NGK 
+0.11 
-0.09 
-0.2 
1999 NGK 
NGK 
-0.13 
-0.05 
+1.0 
NGK 
NGK 
+0.13 
0.0 
+1.0 
3 Absolute measurements 
The absolute measurements were reduced both according to the variations of the digital system 
(section 4) and - up to 1997 - according to those of the photographic system. 
3.1 Declination and Inclination 
Absolute measurements of D were made with the D/-flux on an approximately monthly basis. Also 
the determination of / was included in the measurement routine. Each measurement is based on a 
set of four positions. / was corrected by the pier difference of -0.2’ in the sense of NW minus NE. 
The differences E=/-arctg(Z7H) are shown in Tables 1 .x (x means 1,2, 3 or 4, respectively). 
Additionally, relative measurements of D were carried out with the PVM according to the addition 
field method on a weekly basis. The mean differences c/in the sense of PVM minus Dl-flux of all 
pairs of measurements carried out on the same day were used as instrument constants. Their 
values are as follows: 
d 
Number 
1996 
-23.85’ 
13 
1997 
-23.86 
11 
1998 
-23.95 
10 
1999 
-23.82 
12 
3.2 Horizontal intensity, vertical component and total intensity 
Absolute measurements of Hand Zwere carried out with the PVM according to the 
compensation field method after each relative determination of D.