Baader 1.25″ polarizing filter – Reduces brightness, especially
when used with a Herschel wedge.
The filter can be screwed into 1.25″ eyepieces or adapters and
is used for stepless brightness control when observing the sun
with Herschel prisms. By twisting the eyepiece or the adapter
the brightness changes. This is possible because a
Herschel prism produces a polarized light beam.
Moon observers using a 2″ telescope can
also screw a 2″ polarizing filter into the 2″/1.25″ adapter and this
filter in the eyepiece. To adjust the brightness, that is enough
twisting the eyepiece. Moon observers with 1.25″ focusers can also take part
a Barlow lens and two 1.25″ polarizing filters.
In normal use, the polarizing filter works like a
Gray filter with about 15% light transmission.
2″ filter thread, aluminum frame, plane optically polished surfaces,
Multi-coated, substrate 2mm thick.