LuntLS40FHa#2

Overall results

	Test method	f-ratio	Surface sampled	FSR	FWHM	Delta CWL	Note
Lunt LS40FHa(#2)	Ha lamp	collimated	full aperture 21 mm	12.0 A	0.64 A 0.63 A	+0.48 A +0.50 A

Test of the etalon with the Ha lamp in diffuse light

Optical setup: Ha lamp => diffuser => etalon => Nikon Z7II with 85 mmS f/1.8 lens

Comments:

- The interference patern is quite uniform with fringes having textbook Lorentzian profile.
- The mesurements from the different rings are very consistent.
- Results from 38 mm to 21 mm aperture are quite similar.