The Light Path Inside Of The Herschel Prism; Connecting To The Telescope - Baader Planetarium HERSCHEL PRISM MARK II Instruction Manual

The light path inside of the Herschel prism

The diagram on the right shows the path of light inside
of the Herschel prism. The sunlight enters the prism
from the left. Approximately 4.6% of the sunlight is
directed upwards at a right angle into the eyepiece or
camera for observation. Further grey filters dim
the light even more to a harmless level.
The disproportionately larger, higher-
energy portion of 95.4% of the
radiation passes through the prism
body and would form a focal point in
the "air" far outside the prism housing.
A heat-absorbing special ceramic as a closure
of the light trap ("heat cage") absorbs radiant heat – like
the heat tiles on the space shuttle – without heating the
surroundings too much. The housing, which is closed except for the ventilation slots,
reliably prevents any risk of bright light reaching your eye. Since the "heat cage" is
only connected to the prism housing via four screws, there is practically no heat trans-
fer to the prism itself. The ceramic plate also acts as a viewing screen for the sunlight
beam. Positioning the sun in the centre of the telescope's field of view is thus easy.
The 2" ClickLock
®
With a 15° turn you clamp any eyepiece bombproof – even in winter with thick gloves.
Never use Filters in front of the Herschel Prism:
For manufacturing reasons, the 2" nose piece of the Herschel prism also has a
female M48 filter thread as it is common for 2" filters. In the case of the Herschel
prism, however, no filters must be mounted here, as any filter inserted at this point
will become very hot and thus be destroyed (see also the safety instructions on
page 3). Any optical accessories must be mounted after the prism (i.e. on the eye-
piece side).
The Herschel prism is attached to the telescope in exactly the same way as a 2" star
diagonal. Make sure that it is securely held in the telescope's focuser.
Owners of Diamond SteelTrack
also attach the Herschel prism permanently to the
focuser. This is particularly interesting for purely
solar telescopes and in public use, so that no one
can remove the Herschel prism. To do this, simply
unscrew the 2" nose piece and attach the Herschel
prism to your Diamond SteelTrack
the S58 ring dovetail instead of the eyepiece clamp.
eyepiece clamp is used to hold eyepieces or other accessories.

Connecting to the telescope

focusers can
®
focuser using
®
© Baader Planetarium GmbH | 2024
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