DayStar PE 0.6A#2
The filter was measured using interferometry with an Ha lamp and diffused light.
|DayStar PE 0.6A#2
(asssuming a 1.575 index for mica)
Measurement of the etalon with a Ha lamp
Nikon Z6 with Nikkor 50 mm S f/1.8 lens at f/2 -
center of the etalon - 20 s exposure - 800 ISO - 17 September 2023 - etalon at operation temperature.
Etalon gap index :
The main assumption to be made in the measurement with a Ha lamp is
about the index of the mica gap. A value of 1.575 is assumed (same
value found by spectrometer on other mica-spaced etalons).
The resulting FSR is 26.4.
On this basis, the average value of
FWHM measured over the full diameter of the etalon is 0.95 A (collimated beam).