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110 manuals_110 manuals 6/27/2010 8:16 PM Page 6
Focuser parts description
Focuser locking collar (1) connected to the OTA flange (not shown) and holds focuser on the end of tele
scope. Loosening it will allow you to rotate the focuser to any position.
NOTE: The focuser can be completely removed by unscrewing the locking collar completely and then
pulling the focuser from the OTA flange. This should only be done in rare special circumstances. Please
contact TEC before removing focuser for any reason.
The drag between the Focuser housing (3) and Focuser draw tube (4) can be adjusted by tightening the
Tension adjustment knob (2). Please note: tightening this knob with increase drag only ~ 20%, but will
not completely stop the movement of the focuser draw tube. Tetsion adjustmeent knob and the Fine fo
cusing knob (10) are both plated with fine Gold to avoid any oxidation from continuous finger contact.
Focuser draw tube (4) has laser engraved mm scale, inside it is painted with flat black paint and has a
number of knife-edge baffles to reduce internal reflections at low angles.
Draw tube end cap (5) with Collet locking nut ((7) and Collet sleeve (8) are assembled as one unit. This
unit can be removed by loosing three 6-32 set screws (6) and unscrewing it completely. The Field
Flattener for wide field imaging could than be screw onto the focuser draw tube end.
The Collet sleeve is made of Aluminum, its surface is tumbled and left unanodized to avoid scratching
the barrel of eyepiece or other equipment, also coefficient of friction of unanodized aluminum is higher
than for anodized aluminum.
NOTE: keep the Collet locking nut tichtened at all times to avoid
droping /damaging your equipment!
Coarse focusing knobs (9) and Fine focusing knob (10) have round rubber grips for better tactile
feeling during focusing. Using rubber is also better for focusing at low temperatures.
Right focusing knob can be removed by loosening set screw (11), a Robofocus or other brand of
electrical motors can be installed instead, use 4-40 threaded holes (13) for motor bracket installation.
Fine focusing knob (10) can also be removed by loosening set screw (not shown), to access the set screw
of this knob the rubber grip has to be removed with toothpick.
Please note: the pinion shaft diameter is 1/4", the fine focusing knob shaft diameter is 1/8".
Pinion shaft housing (12) attached to the focuser housing (3) with 4-40 socket head cup screws (15).
Position of the pinion housing with pinion shaft relatively to the rack (installed on the focuser draw
tube), is precisely adjusted by TEC during assembly. Please avoid unscrewing these screws.
Pinion housing plastic screw (14) covers 1/4"-20 threaded hole, the purpose of this hole will be
described ahead.
The Focuser housing (3) also has two 8-32 threaded holes for finder base installation (these holes are on
the left from Tension adjustment knob) not shown on given sketch. If finder base is to be installed on the
focuser housing, make sure the screws being used are of correct length to avoid scratching/damaging
internal parts of focuser housing.
Please contact TEC if you have question about the length of the finder base screws.
WARNING: Do not ever try to disassemble the focuser for any reason, it can not be done without
proper tools and without knowing its internal structure. Attempt to disassemble focuser may end
with focuser parts damage and loosing warrantee. Contact TEC if you have any issues or question
about the focuser.
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