DeltaOHM HD2402, Operating Manual

Page: 30 / 58

HD2402
- 30 -
V1.4
o
t_lim [s] exposure time limit, that is the time period during which the source can
be observed with no problems to the visual system. This value is calculated with
the following procedure:
if L
B_real
< 100 then t_lim > 10000s
(d index satisfied)
if Alpha ≥ 100mrad ⇒
otherwise t_lim = 10
6
/ L
B_real
(c index satisfied)
if L
B_100
< 100 then t_lim > 10000s
(d index satisfied)
If 11mrad ≤ Alpha < 100mrad ⇒
otherwise t_lim = 10
6
/ L
B_real
(c index satisfied)
if L
B_100
< 100 then t_lim > 10000s
(d index satisfied)
if Alpha < 11mrad ⇒
otherwise t_lim = 10
6
/ L
B_11
• Omega [sr] , the solid angle under which the source is seen by the instrument is
supplied by the user:
o
Alpha [rad] angle subtended by the source calculated starting from the Omega
solid angle assuming that the source shape is circular:
Alpha = 2(Cos
-1
(1-Omega/2 π ))
o
Omega [sr] solid angle subtended by the source.
o
L
B
(100mrad) [W/(m² sr)] radiance calculated assuming that the source angular
dimension is 100mrad.
o
L
B
(11mrad) [W/(m² sr)] radiance calculated assuming that the source angular
dimension is 11mrad.
o
L
B
(1.7mrad) [W/(m² sr)] radiance calculated assuming that the source angular
dimension is 1.7mrad.
o
L
B
(real) [W/(m² sr)] real radiance calculated starting from the entered geomet-
ric parameters.
o
t_lim [s] exposure time limit, that is the time period during which the source can
be observed with no problems to the visual system. This value is calculated with
the following procedure:
if L
B_real
< 100 then t_lim > 10000s
(d index satisfied)
if Alpha ≥ 100mrad ⇒
otherwise = 10
6
/ L
B_real
(c index satisfied)