> ~ 
By way of example, the fccal lenght is 105mm, F-number: 4, the angle of 
the field of the. camera lens: 25'20°, the thickness of the glass is 1 mm 
and then if the angle § used actually is 20'as shown in figure 14, 15, 
the following is obtained 
42 43% jar om 6195. 
i, R20) ; vo 7,100, 
Xie «0.024 mm, Hy = 0.56. un 
In this case, if the distance a (in Fig.15) is 1000 mm, it can be 
possible to take & photograph of the object that its width is about ) 
726 um. ‘Any way, if author has the good slit as well as the slit compos- 
ed of the knife-edge using in spectrocope, author will not discuss the 
Yr 
problem above mentioned. 
  
  
  
  
  
  
  
  
  
  
  
  
  
/05 
e mm 
20° 
a 
OP cai 
vi C 
{X ; : 
N17 — US ) t 
/ Jl "A x 
/ , \ Ni 
71 loBiton 42 | p 
ZI. | 
A Nh? 
/05 tan20° ^ /o5 toma, : a 
C 
Tig.14. Fiz.l5 t 
b 
(B) Figure 17 shows the relation between the width of the slit-image 
S 
(the image of the slit used in the light source focussed in the s 
plane I which is perpendicuiar to the camera-axis) and its position on 
S 
the bench I (Fig.16 Xa In the figure. 17, L and P. represent the: camera 
a 
lens and the photographic plate respectively, and Sl is the main slit, 
be