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) |
|---|---|
| 3100 | 1.53 |
| 3200 | 0.94 |
| 3300 | 0.72 |
| 3400 | 0.60 |
| 3500 | 0.52 |
| 3600 | 0.46 |
| 3700 | 0.41 |
| 3800 | 0.37 |
| 3900 | 0.33 |
| 4000 | 0.30 |
| 4100 | 0.27 |
| 4200 | 0.25 |
| 4300 | 0.22 |
| 4400 | 0.20 |
| 4500 | 0.19 |
| 4600 | 0.17 |
| 4700 | 0.16 |
| 4800 | 0.16 |
| 4900 | 0.14 |
| 5000 | 0.13 |
| 5200 | 0.12 |
| 5400 | 0.11 |
| 5600 | 0.11 |
| 5800 | 0.10 |
| 6000 | 0.09 |
| 6200 | 0.08 |
| 6400 | 0.07 |
| 6600 | 0.05 |
| 6800 | 0.04 |
| 7000 | 0.04 |
| 7200 | 0.03 |
| 7400 | 0.03 |
| 7600 | 0.02 |
| 7800 | 0.02 |
| 8000 | 0.02 |
| 8200 | 0.02 |
| 8400 | 0.01 |
| 8600 | 0.01 |
| 8800 | 0.01 |
| 9000 | 0.01 |