© Baader Planetarium GmbH | 2023
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*in this configuration, the polarising filter is installed upside down, with the thread
facing the telescope. This is only possible with linear polarising filters like
# 2408342
;
circular polarising filters only work in one mounting direction. Do not use a polarising
filter with a rotating mount (e.g. from a double polarising filter), as you would not be
able to remove it.
The rotatable filter holder for brightness adjustment with a polarising filter
The biggest innovation of the Cool-Ceramic Safety Herschelprisma Mark II compared
to its predecessor is the revised filter mount, which can now be easily rotated from the
outside via an easy-to-grip adjustment lever
2
. This allows a single 2" polarisation
filter
(# 2408342)
to be permanently mounted in the beam of light. Since the Herschel
prism already partially polarises the light, the image brightness can thus be conveni-
ently adjusted to different magnifications by rotating the filter – without having to
purchase several polarising filters for each eyepiece and/or the 1¼" reducer. This also
means that this filter cannot be forgotten and safe observation of the sun is possible at
all times. The lever
2
can be placed in several positions at the rotating filter holder, so
that it covers the brightness levels from dim to bright.
For visual observation, you can simply use the position that provides a comfortable
image brightness. Always place the filter on the eyepiece side, behind the ND3 –
otherwise, it might get damaged.
When photographing the sun, please note that you will need new flats if you move
the camera or the filter pack.
Baader 7.5 nm Solar Continuum Filter 2" (540 nm)
# 2961581
(included in delivery)
The Solar Continuum Filter (SC filter for short) is a very narrow band line filter (half-
width 7.5 nm nanometres, see transmission curve on the right) at a central wavelength
of 540 nm at maximum transmission. It brings the following advantages for solar
observation:
Most two-lens achromatic refractor
objectives are not equally well correc-
ted across all colours of the spec-
trum. With these lenses, the Solar
Continuum Filter isolates the spec-
tral range that is best corrected for
these lenses. This brings out the best
possible image from an inexpensive
refractor (all other colour ranges are
completely filtered out). This narrow
Note the order of the filters!
To avoid reflections, use the following sequence
Herschel prism - Solar Continuum - ND3 - Filter holder
A polarising filter
must
always be installed behind the ND3,
i.e. directly in the rotating filter holder, otherwise it can be damaged by the heat:
Herschel prism - Solar Continuum - ND3 - Filter Holder - Polarising Filter* or
Herschel prism - ND3 - Polarising Filter - Filter Holder
