Light from the telescope enters the blocking filter (at left), where wavelengths near H alpha are transmitted while the rest are reflected back out. Red H alpha light then passes through the telecentric barlow lens elements to achieve a slower focal ratio, more parallel light beam. The Etalon passes a very narrow range of light wavelengths, but it is sensitive to temperature and light angle. In the built-in Quark device, the Etalon is heated to approximately 100-150°F to control the wavelength passed, and the telecentric barlow controls the angle of light entering the Etalon.
Daystar Bandpass:
Each Quark is warranted to have a FWHM bandpass (when introduced into a focal plane beam of ~F7-F/9) of 0.25 - 0.5.
Combo Quark filters are warranted to have a FWHM bandpass (when introduced into a focal plane beam of >F/25) of 0.25 - 0.5.
A degree of variation from unit to unit will naturally occur, as different FWHM filters are produced and binned into either Chromosphere or prominence specification categories.
A Quark will never be warranted to perform precisely to the standard of a different Quark or Quantum filter, due to the range of acceptable FWHM bandpass within the stated specification standard. More precise certification and smaller FWHM category ranges greatly increase the production and qualification costs of Quark filters due to degree of optical precision and assoicated cost required.