News from Starlight Instruments
Newest Addition: Feather Touch® 3000 Series Focusers
We are pleased to announce the newest addition to our line of focusers - the Feather Touch® FTF3025 Focuser. The 3 inch diameter focuser has a draw tube
travel length of 2.5 inches. This intermediate size focuser is perfect for applications
that need something larger than our
2 inch Crayford-style, but smaller than our 3.5 inch refractor-style focusers.
The FTF3025 Series focuser is similar in design to the FTF3545, but incorporates advanced
features that are ideal for applications which demand precision imaging while also
managing a heavier weight capacity than the 2 inch models.
Currently on the drawing board are a variety of draw tube lengths, ranging from 1.5 inches to
3.5 inches of travel. Also in the works are tube adapter rings for special and semi-custom
applications. If you have custom requirements and/or needs, please do not hesitate to
contact us with details -- our precision machine shop can get your parts made to the most
demanding tolerances!
This focuser comes with our Fine Focus Reduction Unit which allows very accurate
focusing. It is typically a 9:1 planetary reduction assembly that
makes focusing extremely precise and easy. We were the original
developer of this type of system for telescope use and have been
making and improving these for longer than any other manufacturer.
These units have undergone continuous improvement and we believe they are, quite simply,
the best in the industry.
The smooth and precise feel of our Fine Focus Reduction Unit is the key, and it
allows our users to focus precisely with unparalleled
accuracy, speed, and reliability.
The 3000 series focusers can be rotated easily relative to OTA via one Thumb screw. And,
can be detached from the OTA via Thumb screws.
Our standard Tube Adapter Ring allows attachment to a 109mm x 1mm male thread.
Other options will be available as the need arises within size limitations.
Rack and pinion design using a precision fine pitch ½ inch wide Brass rack and matched
hardened Stainless Steel pinion.
Our original Brake Feature is included to allow for easy load adjustment
of the weight on the focuser. This feature also allows locking the
pinion/draw tube when needed.
The end of the draw tube uses a 75mm x 1mm thread to allow other End Cap Options.
And, as with our other focusers, the 3000 series uses internally machined light baffles for
superior light-reducing.
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| FTF3025 Focuser Specifications | Units (Metric) | Units (English) |
|---|---|---|
| Draw Tube Travel | 63.50mm | 2.50 In. |
| Distance from OTA to End of CR End Cap, Racked In | 93.22mm | 3.67 In |
| Distance from OTA to End of CR End Cap, Racked Out | 156.72mm | 6.17 In |
| Opening at entry side of draw tube | 76.20 mm | 3.00 In |
| Draw tube thread, used for accessories | 75mm x 1mm | |
| Draw Tune Drive Mechanism | Rack and Pinion | Rack and Pinion |
| Rack and Pinion Pitch | 72 Pitch | |
| Reduction Unit type | 2.7 Inch Planetary Drive | |
| Reduction Ratio | 9:1 (Approximately) | 9:1 (Approximately) |
| Linear distance per one revolution of pinion | 17.60mm per Revolution | .693 In per Revolution |
| Linear distance per one revolution of Fine Focus knob | 1.960mm per Revolution | .077 In per Revolution |
| Weight Lifting Capacity | 5.5-6.8kg | 12-15 lbs |
| Weight carrying capacity | 5.5-6.8kg | 12-15 lbs |
| Weight of focuser with standard TAR and EC | 1570 Grams | 3.46 lbs |
| Weight of focuser with out TAR and EC, Body only | 1230 Grams | 2.71 lbs |
| Weight of Tube Adapter Ring (TAR) 109mm x 1mm | 200 Grams | .44 lbs |
| Weight of Compression Ring End Cap, (CREC) | 144 Grams | .32 lbs |