Parameters of the Fabry-Perot Interferometers
  Queensgate FPI ICOS FPI
p260 p501 p751
Order (in H-alpha line)235501751
Interfringe (in H-alpha) 28 A (1270 km/s) 13 A (600 km/s) 8.7 A (390 km/s)
Spectral range 5000-7000 A5000-8000 A4500-9000 A
Finesse (in H-alpha) 13 1620
Sp. resolution (in H-alpha) 2.1A 0.8A0.4A
Number of spectral channels24-32 36 40