CASSENS & PLATH BOBBY SCHENK Sextant Handhabung Seite 30

Instructions
Page 15 ______________________________________________________________
The telescope is fixed to the sextant by a knurled knob.
No adjustment is necessary in order to exchange one telescope against another. But care must be
taken to ensure that it is screwed securely to the frame.
Illumination and Replacement of Batteries
Batteries for light are already inserted into the sextant handle when delivered.
The illumination lights up the index mark and drum with vernier. This simplifies measurement
readings at night. Open the sextant handle by using of the knob to change the batteries (2 off type
R6 or AA).
The bulb can be replaced by pulling out the illumination cap of the light leading frame as shown in
the following picture.
Electric
Contact
Care and Maintenance
Precision mechanical instruments must be treated with extra care. They should never be knocked
or dropped. The instrument should either be held with the right hand gripping the handle, or, when
it is being taken out of its case or handed to someone else, with the left hand holding the frame of
the instrument.
A fine hair brush should be used to clean the mirrors, tinted glasses, telescopic lenses and the
graduated arc from dry salt caused by spray water, or dust. In case the mirrors are cleaned this
way or if they are touched accidentally one has to re-adjust them. If these parts are wet, they
should be cleaned carefully with a soft chamois leather of fluff-free linen cloth. A chamois leather
or linen cloth should be used to dry the body of the instrument if it has been exposed to rainwater,
spray or moisture in any other form.
The glass components should not be exposed to direct sunlight if they are wet, as this will cause
brownish stains. A cotton-wool swab soaked in pure alcohol should be used to remove salt residue
from the mirrors and glass components.
Exposing the sextant unnecessarily to direct sunlight should be avoided at all times. Heat from the
sun may cause the cement between the lenses of the telescope to cumble, which will stain the
lenses (sun spots).
Acid-free oil (non resinous) should be applied sparingly to the screw of the drum from time to time.
When the instrument is being placed in its case, make sure that the instrument is dry (otherwise
humid air inside the case may cause fungus attack), swing the shade glasses in storage position,
alidade to zero and close the case carefully.
Exchanging the Mirrors
Generally the exchange of the traditional split view mirror with frame against a fullview horizon
mirror with frame or the other way round is not critical and can be done by the navigator himself.
After installation the mirror position has to be corrected carefully (ref. to chapter "Adjustment of
Horizon and Index Mirror").
(14/Wo/136A)
BOBBY SCHENK Sextant
Remove lamp
cap
Bulb