William Optics ZenithStar 71mm F5,9 ED apochromat
A small-aperture but extremely-portable ED scope at a GREAT price?
The latest ZS 71 ED Doublet is here to fit all your needs!
Excellent mechanics, fit and finish, latest WO 2" Rack &Pinion 2-speed fine focuser now are so good that they can replicate the smoothness and lack of backlash normally associated with a Crayford focuser, but with the huge advantage of much increased mechanical strength.
Lens Design ED glass (Japanese imported Ohara glass) doublet air-spaced, in CNC machined ultra-high precision lens cell. Each lens is Fully Multi-Coated with a special super-high transmission coating (STM Coating) on all surfaces.
Low C.A. Fully baffled to block all extraneous off-axis light rays and prevent glancing reflections, increasing overall contrast. 71mm clear aperture and F/5.9 focal ratio.
Nothing Left to Chance Perfect for EAZY-T Alt-Az Mount. You can slide it directly into the mount without a dovetail plate if you like.Pure William Optics quality fit and finish: powder-painted white CNC-machined aluminum tube Drawtube travel length 80mm with graduated scale.Retractable dewshield, smallest size ever and enhanced portability! Can mount a WO 2'' star diagonal and other 2�� accessories.
Astrophotography ED scope Fast focal ratio for excellent exposure on photography usage. New Flattener Available (optional) .Perfect for piggybacking as a guide scope.! !
Wonderful WO Microfocuser William Optics new rotatable Rack & Pinion focuser, smooth and precise, ideal during astrophotography; can be fully locked and will not flex or slip even with a very heavy camera combination. Adjustable focuser tension. Super-smooth and reliable 1:10 micro focuser for fine focusing during imaging and visual observations alike. Aluminum fine knob protection cover is included.
Attention to Packaging The basic package includes the OTA only.Carry-on size: you do not have to leave this treasure home!
|Focal Ratio ||F/5.9|
|Focal Length ||418 mm|
|Objective Type ||ED Doublet, Air Spaced, |
Fully Multi-Coated, SMC coating.
|Resolving Power ||1.58"|
|Limiting Magnitude ||11|
|Lens Shade ||Retractable|
|Focuser || 50.8mm(2") Rack & Pinion Focuser|
with 1:10 Dual Speed microfocuser
80 mm (3.2")Focuser Travel Length
360° Rotatable Design
|1.25" Adapter||Brass Compression Rings|
|L-type Mount |
Integrated L Bracket (fits SmartEQ mount)
|Field Stops|| Baffles |
|Tube Diameter|| 93 mm (3.66") |
|Tube Length || 310 mm Fully Retracted|
355 mm Fully Extended
|Tube Weight||6 lbs. (2.7 kg)|
Specification for Apochromatic Lenses
All WO refractors objective are double tested and inspected before shipping to our customer, these telescopes are free of coma and astigmatism.
Since all individual lens surfaces are machine coated sometime it could have visual imperfections which do not affect the objective optical performance.
Dimensions of scratches and points shall not exceed the following values:
Surface finish class Scratches Points Accumulation of defects Width,not more, mm Total length, not more, mm, Diameter no more,mm, Quantity, no more Diameter.
|Scratches||Width, not more, mm||0.025mm|
|Total length, not more||1/4 of total lens diameter. |
Quantity no more 3
|Dots or spot points||No more, mm||0.4mm|
|Quantity, no more||3|
|Accumulation of defects||Limited area, mm||0.8mm^2|
|Total area of scratches and points, no more, square mm||5.8mm^2|