About this product
Part Number: A-Z73BU
The NEW William Optics Zenithstar 73 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).
It's fast f/5.9 focal ratio and compact size makes it ideal for convenient wide field astrophotography or piggybacking.
Supplied with mounting rings, guiding rings and Vixen-style dovetail bar.
CNC machined aluminium for a superior fit and finish.
Dual speed 2.5" 1:10 R&P focuser.
Available in Blue, Red or Gold 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.
What's in the box
- Telescope OTA
- Mounting Rings
- Guidescope Rings
- Vixen-Style Dovetail
|Aperture ||73 mm |
|Focal Ratio ||F/5.9 |
|Focal Length ||430 mm |
|Objective Type ||ED Doublet, Air Spaced, |
Fully Multi-Coated, SMC coating.
|Lens Shade ||Retractable |
|Tube Diameter ||93mm (3.66") |
|Tube Length ||310 mm Fully Retracted |
|Tube Weight ||5.5 lbs. (2.5 kg) |
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