Basically $3300 USD (2810 Euros without VAT) for a Quark.
I'm not sure I'd go that far, as the Quark is not given any bandpass specification or additional qualification, whereas the Solar Spectrum SunDancer filter is:
Half-width (FWHM) of 0.6±0.1Å at an effective focal ratio of f/30
One of the major disadvantages of the mica filters (and heated substrate filters in general) is the tuning temperature lag. This makes filter tuning completely dependent on the observers ability to determine what is on verses off-band. I note the plethora of off-band images posted here and elsewhere.
This filter series represents a refinement of the the early and current DayStar T-Scanner ($3100 for a "0.6" A*) tilt-based filters which have a very narrow temperature operating range, and the TEC ability to cool with extremes of weather - such as we recently experienced tin the Pacific Northwest (and presumably will continue due to worsening climate change effects - if not get worse), makes this filter system a serious contender for a near-the-focus filter. This gives the filter a rapid tuning ability identical to tilt tuning and air-pressure tuning enjoyed by air-spaced etalons.
* Note that DayStar does not qualify at what f-ratio this FWHM specification is attained at.
Edited by BYoesle, 19 September 2021 - 03:26 PM.