Lunt Telescope Focuser
Precision Focus Control For Lunt Solar Scopes
Lunt offers a focuser to match nearly every one of its solar telescopes, from a compact helical unit for small refractors up to a two inch dual speed rack and pinion. Choosing the right one comes down to the thread interface on your blocking filter or rear cell, the weight of the gear you plan to hang off it, and how fine you need the final adjustment to be.
The 1.25 inch mini helical focuser threads T2 male to T2 female and gives ten millimeters of non rotating travel with a brass compression ring and a locking collar. The 1.25 inch rack and pinion steps up to a rotatable draw tube, half an inch of travel, positioning accuracy of plus or minus 0.002 inch, and a load rating of six to eight pounds.
For imaging, the 10:1 versions matter. The 1.25 inch rack and pinion with 10:1 fine focus suits the LS40THa and LS50THa, while the two inch rack and pinion carries roughly 55 to 60 mm of travel, a 10:1 reduction, and works with ZWO EAF and Optec FocusLynx motor kits. At the top of the range, the SLF1.5 and SLF2.5 two inch draw tube focusers are Starlight Instruments Feather Touch units built in a Lunt specific configuration. Remember that any solar use still requires the telescope's own certified solar filtration.
Key Features
- Helical Option - the LSMINI/1.25 gives ten millimeters of non rotating T2 to T2 travel with a brass compression ring and locking collar.
- Rack And Pinion - machined from aluminum and brass with a rotatable draw tube and backlash under 0.001 inch when properly adjusted.
- Ten To One - the 001-148 and the two inch 001-143 add 10:1 dual speed reduction for critical focus at high magnification.
- Load Capacity - six to eight pounds on the 1.25 inch rack and pinion, and 2.5 to 3.0 kg on the two inch version.
- Starlight Feather Touch - the SLF1.5 and SLF2.5 two inch draw tube models are Starlight Instruments Feather Touch focusers supplied in a Lunt specific configuration.
- Feather Touch Upgrade - the SLF2.5 delivers 2.5 inch of travel, 0.01 mm repeatability, and hardened stainless steel running surfaces.
- Motor Ready - the two inch rack and pinion accepts ZWO EAF and Optec FocusLynx or ThirdLynx motor focus systems.
| Specifications | |
|---|---|
| Type | Telescope focusers, helical and rack and pinion, for Lunt solar and universal tubes |
| Model / SKU | LSMINI/1.25, 001-147, 001-148, 001-143, SLF1.5, SLF2.5 |
| Manufacturer | Lunt for the mini helical and rack and pinion models; Starlight Instruments (Feather Touch) in a Lunt specific configuration for SLF1.5 and SLF2.5 |
| 1.25 inch mini helical (LSMINI/1.25) | T2 male to T2 female, 10 mm travel, non rotating, brass compression ring, locking collar |
| 1.25 inch rack and pinion (001-147) | 0.5 inch draw tube travel, rotatable, accuracy plus or minus 0.002 inch, load 6 to 8 lb |
| 1.25 inch rack and pinion 10:1 (001-148) | 10:1 dual speed fine focus, listed for LS40THa and LS50THa |
| 2 inch rack and pinion (001-143) | approximately 55 to 60 mm travel, 10:1 reduction, M68 or M90 rear thread |
| 2 inch Feather Touch, 1.5 inch travel (SLF1.5) | Not published |
| 2 inch Feather Touch, 2.5 inch travel (SLF2.5) | 2.5 inch travel, 0.01 mm repeatability, 52 mm threaded draw tube, lifts 2.5 kg or 5.5 lb |
| Eyepiece side | 2 inch compression ring with a 1.25 inch adapter included on the 001-143 |
| Materials | CNC machined aluminum and brass; hardened stainless steel running parts on Feather Touch models |
| Motor focus | 001-143 compatible with ZWO EAF and Optec FocusLynx or ThirdLynx |
| Telescope fit | SLF2.5 listed for LS130MT and LS152THa; 001-143 standard on 60MT, 80MT and 100MT |
| Backlash | under 0.001 inch on the 1.25 inch rack and pinion; 0.0 mm quoted for the Feather Touch |
| Solar safety | for solar use only behind the telescope's own certified solar filtration |
| Shipping weight | 2.0 lb for LSMINI/1.25, 001-147 and 001-143; 3.0 lb for SLF2.5; others Not published |
| Warranty | 5 years from date of purchase, original purchaser, manufacturing and workmanship defects |
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