Fabry-Perot DUAL etalon mode is tested

17th July 2011: A milestone was reached tonight.... we achieved dual etalon mode calibration ring images with RSS! Getting the rings from two separate etalons aligned and accurately tracking each other with wavelength has been a long time coming. The etalon system was designed by the Fabry-Perot guru Ted Williams from Rutgers University ten years ago,  and the final system is still undergoing commissioning.

To accomplish the image shown below we (Ted Williams, SALT engineer Peter Menzies and SALT Astronomer Nic Loaring) have taken hundreds of calibration images, conducted numerous mechanical shimming exercises and generally pulled our hair out over the past two years at the telescope!

The image below shows a calibration ring of the Ne 653.2 nm emission line taken in the 653 nm narrow band filter with both the low resolution ("small gap") and medium resolution ("medium gap") etalons inserted. This combination of etalons will be used for Fabry-Perot observations at medium resolutions.

RSS Fabry-Perot image showing a Ne 6532 calibration ring taken in dual etalon mode.

And if that doesn't impress you.. check out the smile below!

Fabry-Perot mode RSS instrument team specialist Ted Williams - you'd never guess that he was pretty chuffed! (SALT Astronomer Encarni Romero-Colmenero is in the background).