About this product
Part Number: A-Z61IIGD
Latest 2020 model with Bahtinov Mask cap, CNC saddle handle, longer dovetail & Soft Case.
The William Optics Zenithstar 61 II APO features an air-spaced doublet lens with fully multi-coated optics and an Ohara FPL-53 ED glass element for sharp, high contrast images virtually free of false-colour.
Provides high resolution images when used for astrophotography or wildlife photography and is a convenient ultra-portable telescope for visual astronomy (think binocular astronomy targets).
The fast f/5.9 focal ratio and compact size make it ideal for convenient wide field astrophotography or piggybacking.
Convenient rotatable L mounting bracket for easy framing of target.
CNC machined aluminium for a superior fit and finish.
Dual speed 2" 1:10 R&P focuser.
Available in Red, Gold or Space Grey anodised.
Ohara FPL-53 vs FPL-51 ED Glass
The dispersion properties of ED and SD glass elements are important in determining the overall colour correction. The abbe index is used to quantify the 'partial dispersion' of a particular glass. Pure Fluorite offers the highest partial dispersion at around 94.99 V, Ohara FPL-53 glass is very close to Fluorite at 94.93 V and is often referred to as Synthetic Fluorite. FPL-53 is also noticeably better than Ohara's lower spec' FPL-51 glass which offers an abbe index of 81.54 V.
- 61mm diameter, 360mm focal length, f/5.9
- Two element APO design using FPL-53 glass
- 2" R&P Focuser for smooth, stable and reliable focusing
- Integrated CAT Handle bar with Vixen-style Finder Shoe Clamp - great for guide scopes!
- Integrated Bahtinov Mask for easy, precise focusing
- CNC clamp ring with saddle handle bar and longer dovetail makes balancing and mounting much easier and more rigid
- Soft padded case
- Tube length: 245mm retracted / 315mm extended
- Tube Weight: 2.2kg
Telescope Field of View Simulator
What's in the box
- ZenithStar 61 OTA
- 2" to 1.25" Adapter
- OTA Mounting RIng
- Cat Handle / Finderscope Clamp
- Vixen-style Dovetail
- Soft padded case
|Aperture ||61mm |
|Focal Ratio ||F/5.9 |
|Focal Length ||360 mm |
|Objective Type ||Air-spaced doublet with fully SMC multicoated optics and Ohara FPL 53 ED element. |
|Image Circle ||Z61 Φ 41mm / Z61 with Flat 61 Φ 43mm |
|Limiting Magnitude ||10 |
|Lens Shade ||Retractable |
|Focuser ||50.8mm (2") R&P Focuser with 1:10 Dual Speed micro-focuser, 75 mm Focuser Travel Length |
|1.25" Adapter ||Compression Rings |
|Mount ||Vixen-style Dovetail |
|Field Stops ||Baffles |
|Tube Length ||245 mm Fully Retracted |
315 mm Fully Extended
|Tube Weight ||2.2kg |
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