William Optics 1.25" 90 degree Erecting Prism

William Optics 1.25'' 90 degree Erecting Prism


Incoming - Shipped 30-40 working days.

Model:  WOerectPrism1.25-90
Part Number:  D-EP90-125
Brand:  William Optics

William Optics 90° Erecting Prism with helical focuser for fine adjustment.

Turns upside-down views right-side-up and gives correct left-to-right orientation. 

Works with 1.25" eyepieces and telescopes with 1.25" eyepiece holders.

  • Large, high-quality BAK4 erecting prism with anti-reflection coating for brightness and contrast.
  • Helical focuser with 15 mm of travel for fine focusing adjustment.
  • Internally matte blackened to reduce internal reflections.
  • Threaded for 1.25" filters.
  • Made from black anodised aluminium.

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Average Rating (2 Reviews):  
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Rating (max 5):  
Wednesday, 25 May 2016  | 

OK not everyone wants an erecting prism but I did! The build quality of this 90 prism is very solid and the optics are good with no perceivable aberrations to my ageing eyes. Much better than the 45 prism that came with my scope. Also the inbuilt helical focuser is a bonus and acts as a fine focus once the scope is focused and does not vibrate the set up. I now don't get back ache with this 90 diagonal in place - highly recommended for quality with ecconomical cost.

Rating (max 5):  
Alternative to dual focusers
Friday, 8 January 2016  | 

Wonderfully built and with smooth action. A lovely alternative solution if you have a stock rack and pinion focuser. Especially so if you want to keep the original look of a classic refractor.
It gives very fine focussing equivalent to dual speed. The prism provides correct views with minimal effect on observing. We compared it with a WO dielectric on the double star Wasat and found it hard to find any difference in views.
Will definately recommend this as value for money and an essential bit of kit.

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October 2017 / View Older
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