William Optics Zenithstar 73 APO

William Optics Zenithstar 73 APO


In stock - Shipped 1-2 working days.

Model:  wo_zs73_gd
Part Number:  A-Z73GD
Brand:  William Optics

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  • Telescope OTA
  • Mounting Rings
  • Guidescope Rings
  • Vixen-Style Dovetail

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.

Product Specifications

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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Customer Services Report
December 2017 / View Older
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