TEC APO 160, User Manual

FEATHER TOUCH FOCUSER MODEL 3545

Care and use of the Feather Touch 3545

The Feather Touch 3545 was a collaborative design effort between Telescope Engineering and Starlight
Instruments for TEC’s line of fine refractors. It was designed to provide the user the with the best possible
control while focusing using a 9:1 fine focus reduction assembly along with other features that make the use
of the telescope simple and functional. All efforts were taken to design it with the best available materials and
technology to achieve long-lasting functionality and reliability.

Part Description

6.1

OTA Focuser Mounting Flange 

6.2

Focuser Locking Collar 

6.3

Locking Collar Stems 

6.4

Tension Adjustment Screw 

6.5

Finder Base Screw Holes (Plugged 

with (2), 8-32 Button Head Screws) 

6.6

Focuser Housing 

6.7

Coarse Focus Knobs 

6.8

Fine Focus Knob 

6.9

Draw Tube with mm scale

6.10

Draw Tube End Cap 

6.11

Draw Tube End Cap Locking Screws 

6.12

Eyepiece Collet Locking Nut 

6.13

Eyepiece Collet Sleeve 

6.14

Plug with TEC logo

Description of Design Features 

1. The Feather Touch 3545 achieves excellent focusing
capability using a 9:1 Planetary Reduction Assembly cou-
pled to a fine focus knob (fig. 6.8). The fine focus knob
should be used once the image is close to focus and final
tweaking is required. 
2. The two coarse focusing knobs (fig. 6.7) on each side
of the focuser allow quick rough positioning of the eye-
piece or imaging equipment. They are coupled to the rack
and pinion set and the fine focus knob. 
3.  The assembly incorporating the focusing knobs, the
pinion and it’s housing is called the pinion assembly (not shown). This assembly is attached to the focuser
housing using (2) 6-32 socket head cap screws. The position of the pinion assembly relative to the rack, is pre-
cisely adjusted by Starlight Instruments using 4 flat bottom set screws (internal to the pinion assembly) to pro-
vide the minimum amount of backlash between the rack and the pinion for ease of operation. The other adjust-
ment that is made is to align the pinion axis to be parallel to the rack face.

NOTE: It is possible to reverse the pinion assembly for left handed preference but Starlight Instru-
ments does not recommend the user reversing this assembly because of possible misalignment resulting
in a loss of performance or possible damage. 
Please contact Starlight Instruments or TEC if this change is desired. 

6.1

6.2

6.5

6.3

6.7

3

6.4

6.11

6.12

6.13

6.14

6.7

6.8

6.6    6.9    6.10