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.
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.
University series filters are designed to operate unheated on the lower of the two Na D emission
lines; and can be heated to accomplish transmission on the higher of
the two Na D lines, making doppler studies possible by photographing in
each line and derriving difference images after subtracting an average
solar velocity image. This process is referred to as a dopplergram
velocity image, reveals the surface motions associated with
Mount Wilson Solar Observatory
filters have until now been primarily used for research purposes only,
performing doppler and supergranulation studies. Narrow bandpass Na D
line filters have also been used in deep-sky observations of IO, but
with significantly larger apertures.
DayStar Sodium Filter assemblies
||0.4Å Single cavity Amateur T-Scanner filter system $4500.00
- suitable for visual or photographic observing
|0.4Å Single cavity University series filter system $7200.00
- suitible for photographic and visual observing
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.