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SkyWatcher 90 Degree Erecting Prism

SkyWatcher 90 Degree Erecting Prism

If you look through your telescope with the standard mirror or star diagonal installed, you will notice that objects may be either upside down, flipped so that you see a mirror image, or a combination of the two. This is fine for observations of celestial objects, but it can be a little confusing when you are trying to track a boat as it moves through the water, or an eagle as he flies towards his perch.

Luckily, this is an easy problem to correct. Simply remove the standard diagonal from the telescope’s focuser or visual back, and install the Erect Image Diagonal. Now, when you insert an eyepiece, objects will be right side up and left-to-right correct.

Customer Reviews

  Worthwhile change  I changed the 45 degree prism that came with the scope for the 90 and I'm very happy with the change. It gives you a better viewing position. Service from Harrisons is spot on.  (18/11/2017) Harry - Cambridge


Our standard delivery charge for most of the UK is £2.95. All orders are shipped promptly, lower value items are sent Royal Mail 1st class and higher value or larger goods are shipped via reputable courier. All goods are shipped fully insured with FEDEX, UPS, DPD and Royal Mail, we do not use budget courier services, please note we can only ship to UK mainland addresses. We are not able to ship to forwarding agents or PO boxes.

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SkyWatcher 90 Degree Erecting Prism

MPN: 20377





Price: 34.00


Available again soon - A 90 degree erect image diagonal for correct image views in daytime with Refractors, SCT's and Maksutovs. A quality coated prism designed to accept any standard 1.25" eyepiece, this prism will fit Telescopes with a 1.25" focuser.


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