La Silla Extinction Coefficients

Extensive extinction measurements were made by Dr. H. Tug, using the 0.6-m Bochum telescope (see below). No correlation was found between extinction coefficients and direction of observation, and measurements made during photometric nights were found not to differ by more than 2% at 500nm. Note that natural phenomena (such as the Mt. Pinatubo volcano) can significantly change the atmospheric extinction, and so we advice observers to make their own extinction measurements during their observations. A more detailed discussion of extinction on La Silla can be found in the ESO Messenger #11, December 1977, and the article by Burki et al. (1995, A and AS, 112 , 383B).

The following table gives the extinction (in magnitudes per airmass) for different wavelengths as measured at La Silla. The data were taken from THE ESO USERS MANUAL 1993.

Wavelength
(Angstroms)
Extinction
(Mag/airmass)
31001.53
32000.94
33000.72
34000.60
35000.52
36000.46
37000.41
38000.37
39000.33
40000.30
41000.27
42000.25
43000.22
44000.20
45000.19
46000.17
47000.16
48000.16
49000.14
50000.13
52000.12
54000.11
56000.11
58000.10
60000.09
62000.08
64000.07
66000.05
68000.04
70000.04
72000.03
74000.03
76000.02
78000.02
80000.02
82000.02
84000.01
86000.01
88000.01
90000.01