William Optics ZenithStar Z61II 61mm f/5.9 Doublet Apo Refractor - Space Gray

Product Details

ZenithStar 61 Doublet Apochromatic Refractor

1. Ultra-Portable Apochromatic 61mm Refractor 

The William Optics ZenithStar 61 Apo refractor combines superb color-corrected optics, extreme portability, and rock-solid built quality into a versatile telescope for on-the-go visual observation and astrophotography. This little scope is an ideal instrument for wide-field visual sweeps of stars and nebulae along the Milky Way, lunar and solar observation (with an optional solar filter), and daytime nature observation. It also makes an excellent astrograph for imagers who wish to take advantage of large-sensor DSLRs and astronomy cameras to capture wide and colorful vistas in the night sky.

2. Razor-Sharp Optics and Superb Build Quality

The 61mm f/5.9 apochromatic doublet objective in the ZenithStar Apo is made with FPL53 glass with superior dispersive properties and color correction compared to less expensive FPL51 ED glass. The color correction of FPL53 is very close to that of pure fluorite glass, which is why FPL53 is sometimes called ‘synthetic’ fluorite. This glass results in an extremely high degree of color correction, even in a relatively simple and affordable doublet objective.

While the ZenithStar 61 telescope weighs just 2.15kg (4.7 lbs), it has the solid build and high-quality feel common to all William Optics refractors. The beautiful metal tube includes a retractable dew shield and incorporates internal baffled field stops to reduce stray light. Fully retracted, the tube length spans just 250mm.

3. Ideal for Visual Observation and Imaging

As you might expect with a quality apo refractor, the William Optics ZS 61 is a superb instrument for taking wide-field astrophotos with DSLRs or dedicated astronomy cameras. The scope's optics provide a 41mm-diameter image circle, and with an optional William Optics field flattener, a full 43mm image circle to fill the sensor of most any camera.

4. Dual-Speed Rack and Pinion Focuser

The 2" rack-and-pinion focuser includes a coarse focus knob and a 10:1 fine focus adjustment knob with protective cover. The coarse-focus knob includes a thermometer to help you track temperature changes during your observation sessions so you know when you may need to adjust focus. The focuser has a full 75mm of travel length, a drawtube locking screw with tension adjustment, 1.25" adapter with compression ring, and pre-drilled holes for red-dot finders.

5. New - Handle/Saddlebar, Ring, and Dovetail Rail

New in this Gen II version is a convenient CNC-machined carrying handle mounted on top of the mounting ring. A dovetail in the handle accommodates an additional set of rings for a guide scope (guide scope rings and guide scope sold separately). On the bottom of the mounting ring is a new reversible dovetail with a Vixen rail on one side and an Arca Swiss mount on the other for mounting the scope to a camera tripod for grab-and-go terrestrial and astronomical observation. This scope is identical to the Gen I version except for these changes (the Gen 1 features a simpler mounting ring with a shorter L-base).

6. Bahtinov Mask and Soft Case

The William Optics Z61 features a patented objective lens cover that doubles as clear Bahtinov focusing mask. This makes it a snap to achieve sharp focus when setting up for astrophotography. A soft carry case is also included with this telescope.

This little scope matches perfectly with a William Optics 2" star diagonal and eyepieces with 5mm to 40mm focal length for visual use.

7. Specifications:

• Focal Length: 360mm
• Diameter: 61mm
• Aperture: f/5.9
• Camera Format: APS-C, Full Frame
• Focuser: 2" R&P Focuser
• Image Circle: 41mm (43mm with the optional William Optics flattener)
• Recommended Flatteners: Flat61A, Flat61R
• Tube Length (Fully Retracted): 250 mm
• Tube Length (Fully Extended): 320 mm
• Dew shield OD: 80mm / 3.14"
• Tube Weight: 4.7 lb (2.15kg)
• Interchangeable T-Mount (sold separately): Canon EF, Nikon F, Sony E Pentax, Micro Four Thirds, Fuji FX
• Case size (outside dimensions with included foam): 13 x 11.5 x 5.5"
• Weight with case: 6 lb - 6 oz

All William Optics telescopes come with a 2-year manufacturer warranty

What's in the Box

• ZenithStar 61
• Patented clear Bahtinov mask cover
• Dual-speed 2” focuser
• Saddle/handlebar
• Mounting ring
• Dovetail rail
• Soft carry case

Other Information

• Country of Manufacture: Taiwan