DayStar's Quantum range of solar filters are designed for professional and serious amateur applications and offer absolute precision control over wavelength transmission. The PE grade series is designed for professional research studies and applications in which precision homogeneity and on-band transmittance values across the substrate surface are required. These filters require additional quality control steps and additional fabrication and testing time.
DayStar is proud to offer Sodium Na- D line (5895.9Å ) filtering systems for visual and photographic studies. Sodium filter assemblies are designed for sub-angstrom observations with single-cavity design. Sodium lines are very narrow, but very bright. A very narrow filter of < 0.5Å is necessary to properly isolate the line from the continuum. The resulting image depicts high detail in granulation, supergranulation and P-modes.
Sodium also shows impulsive-phase flare eruption kernels. Na D is a low excitation line emitted when the low chromosphere is heated, usually at footpoints of flux loops passing through a flare, as sodium D line reflects the lower chromosphere. Visual and photographic images reveal type image as Calcium, revealing granulation, but are much brighter and more easily visible.
Short lived solar flare flashes in Na D line - Photo by Greg Swaim -DayStar Filters 0.4Å Sodium D line filter
The housing offers live LCD readout of the filter's wavelength output (accurate to 0.1Å) and red /blue wing shift buttons that can precisely tune wavelength up or down for Doppler studies. The unit operates at 12VDC for field or battery use and includes a serial port for computer control capability for on-screen display of filter readout.
PE grade filters are manufactured and qualified to a spectral uniformity in CWL (Central Wavelength) accuracy of ± 0.05 ångström. DayStar's high resolution etalon mapping equipment offers qualification certified accurate by independent testing with etalon transmission sample sizes of 5mm, 2mm or 1mm sample sizes with certification printouts available on new PE filter purchases.
Note: These systems require an energy rejection pre-filter and F/30 focal ratio for onband operation. Standard yellow glass DayStar Energy rejection filters provide sufficient off-band energy rejection, as do dielectric 'hot mirror' coated pre-filters.