ASTRONOMICAL GLOSSARY
This page aims at providing some information about general units and systems employed in astronomy.
PHOTOMETRY
|
Magnitude
|
Light ratio
|
|
0.5
|
1.6
|
|
1
|
2.512
|
|
1.5
|
4
|
|
2
|
6.31
|
|
3
|
16
|
|
4
|
39
|
|
5
|
100
|
|
Diameter (mm)
|
Light ratio (Magnitudes)
|
|
200
|
1
|
|
250
|
0.5
|
|
300
|
0.9
|
|
400
|
1.5
|
|
500
|
2
|
|
600
|
2.4
|
|
800
|
3
|
|
1000
|
3.5
|
|
1500
|
4.4
|
|
2000
|
5.0
|
|
3000
|
5.9
|
|
3600
|
6.3
|
|
4000
|
6.51
|
|
5000
|
7
|
|
6000
|
7.4
|
|
8000
|
8
|
|
Band
|
bandwidth (nm)
|
Central wavelength (nm)
|
|
U
|
75
|
350
|
|
B
|
75
|
420
|
|
V
|
100
|
550
|
|
R
|
100
|
650
|
|
I
|
150
|
800
|
|
J
|
190
|
1.228
|
|
K
|
360
|
2.216
|
|
H
|
300
|
1.650
|
|
K'
|
390
|
2.120
|
|
L
|
390
|
3.800
|
|
M
|
381
|
4772
|
|
N
|
5470
|
11055
|
|
N1
|
720
|
8361
|
|
N2
|
1570
|
9787
|
|
N3
|
1150
|
12819
|
|
Q0
|
3230
|
18666 |
Atmosphere transmission
ASTROMETRY
The next plost shows the atmospheric refraction offset versus the zenithal distance T=10°C : blue curve is for a pressure of 750mB and red for 1000mB.
