Front Mounted Filter Design
Front mounted Ha filters use many
of the same components as rear mounted filters. An ERF comes first followed by an Etalon. The etalon is air spaced to provide thermal stability and have a central obstruction to maintain a
precise separation. Light travels through the telescope and into the diagonal
which houses the blocking filters.
An optional knurled knob on the
Coronado filter housing allows you to tilt the filter.
Tilting the filter changes the wavelength of the primary passband peak,
allowing the filter to be
"tuned" to nearby wavelengths to either do temperature compensation or
to see strongly
Doppler-shifted features. Tilting actually broadens the filter passband
a bit, which can
result in a reduction of contrast if carried too far.
A feature moving towards the
observer will have its light shifted towards the blue end of the
spectrum, while a feature moving away will have its light shifted deeper
into the red part
of the spectrum.
Why Ha? |
The View |
What you see |
The Chromos |
Ha Emission |
Bandwidth |
Main Designs |
Ha Components |
Rear Filters |
The Etalon |
Front Filters |
Coronado filters |
DayStar Filters |
Solar Spectrum Filters
