Main page
Direct images
Scanning Fabry-Perot


Back to SAO web page

Last update:1 Mar 2024
This page is designed by A.V. Moiseev

Spectral Camera with Optical Reducer for Photometric and Interferometric Observations - 2

Scanning Fabry-Perot interferometers (FPI)

Observations with the FPI consist of successive acquisition of a few dozen images of interference rings from the object (or from a calibration lamp) when changing the optical path between the parallel plates. The radius of the rings is a function of wavelength and gap between the plates of the interferometer. The complete set of such images which fills the free spectral range of the interferometer is called 'a scanning cycle'. After data reduction images are collected in a data cube. Control of the scanning (change of the gap between flat reflecting plates) is managed by the controller CS100 IC Optical Systems Ltd., connected with a computer. The description of observations and data reduction is presented in the papers:
SCORPIO-2 has a set of bandpass filters which cut the desired narrow spectral range around the emission lines H-alpha, [OIII]5007, [NII]6548,6583, [SII]6717,6731. You can use this IDL-programm for chose an optimal filter for desired systemic velocities of target galaxies.

The piezoelectric interferometers were mad by IC Optical Systems Ltd. (early name - Queensgate).

The main parameters of FPI (in the H-alpha spectral range).
  IFP20 IFP186 IFP501 IFP751
Order 20186501751
Interfringe 328 A 35 A
(~1600) km/s)
13 A
(~600 km/s)
8.7 A
(~390 km/s)
Sp. resolution 20 1.7 A 0.8A0.4A
Finesse 16 21 1620
Number of spectral channels tunable filter40 36 40

The photo shows IFP751 mounted into SCORPIO-2 during tuning procedures Sorry, this page is under construction