454 
RK 820 stereomicroscope - Drawing: 
tilting possibility of eyepiece head 
(+40°; -40°) 
Another characteristic that distinguishes the RK 820 is the ergo 
nomic, person-adapted tilting ability of the eyepiece head which 
normally is 20° and can be varied by +/- 40°. 
The optical data of the possible options with the stereomicrosco 
pe are the following: 
■ The eye distance can be adjusted between 47 and 120 mm thus 
offering an adaptable and viewer-friendly possibility. 
■ The zoom system in the basic device has a zooming factor of 
8 to 1 with a magnifying ratio of 0.425 to 3.4. 
The magnification of the system depends on the eyepiece, 
zoom, and supplementary lens magnification. 
■ The system has 9.1 x and 13.7 x eyepieces whose magnifying 
ratio can be considerably increased by means of the 4.17 x and 
6.25 x front objective lenses. 
By exchanging the eyepieces and front objective lenses the 
following magnifications can be achieved: 
Eyepieces 
Front objective 
Lenses 
System 
Magnifications 
9.1 x 
3.8 x - 31 x 
9.1 x 
4.17 x 
16.1 x-129 x 
9.1 x 
6.25 x 
23.8 x - 191 x 
13.7 x 
- 
5.7 x - 46 x 
13.7 x 
4.17 x 
24.1 x-193 x 
13.7 x 
6.26 x 
35.6 x - 285 x 
. 
The working distance of the RK 820 to the light table surface 
results from the different use of the front objective lenses. 
Supplementary Lenses 
Working Distance 
_ 
100.0 mm 
4.17 x 
12.8 mm 
6.25 x 
3.3 mm 
RK 820 Stereomicroscope and accessoires