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View the Latest Diagonals & Prism Reviews

Item
Submitted By
William Optics SCT Thread Adapter for 2
William Optics SCT Thread Adapter for 2" Diagonal
5.0
William Optics SCT Thread Adapter
This adapter allows the William Optics 2" 45-deg Erecting Prism Diagonal to attach to an SCT type telescope. In my case it was an 8" Meade LX-200 telescope. The 2" nose-piece from the Williams Optics Diagonal is removed (i.e. unscrewed) and replaced...
GSO 2
GSO 2" 90-deg 99% Quartz Dielectric Mirror Diagonal for Refractors
4.0
Excellent Diagonal for the money
I bought this diagonal as my newly purchased refractor did not have one. This one caught my eye and I checked other people's reviews. It was well received and the price is very competitive. I will second that sentiment here.
GSO 2
GSO 2" 90-deg Mirror Diagonal for Refractors
4.0
Excellent Diagonal
This is a excellent diagonal for the money. I have a GSO 90mm refractor for what I bought this for what a difference from the factory 1.25" diagonal. Far sharper and brighter images.The only negative is the eyepiece can catch on the way down the diag...
GSO 2
GSO 2" 90-deg 99% Quartz Dielectric Mirror Diagonal for SCTs
4.0
Nice Diagonal!
Really nice diagonal. Very bright and performs well. Great deal from Agena. Recommended!
GSO 2
GSO 2" 90-deg 99% Quartz Dielectric Mirror Diagonal for SCTs
5.0
Works with Meade Series 4000 f/6.3 Focal Reducer
The Meade Series 4000 f/6.3 Focal Reducer/Field Flattener for Schmidt-Cassegrain Telescopes is a nice accessory but it has limitations when used with some 2" diagonals as you can't ever reach focus. Because of the shorter light path of the GSO 2" ...
GSO 2
GSO 2" 90-deg 99% Quartz Dielectric Mirror Diagonal for SCTs
5.0
One small problem to be aware of...
From the product description: "The 1.25"-2" adapter is also threaded to accept 2" filters." Yes you can screw a 2" filter into the adapter but some 1.25" eyepieces may contact the filter and damage it. A parfocal ring on the eyepiece or a short 2...
William Optics SCT Thread Adapter for 2
William Optics SCT Thread Adapter for 2" Diagonal
4.0
Nice piece!
Nice adapter to turn your WO refractor diagonal into an SCT diagonal.
GSO 2
GSO 2" 90-deg 99% Dielectric Mirror Diagonal for SCTs
5.0
GSO 2" diagonal
Replaced the 90 degree 1 1/4 on my Celestron 8SE. I wanted some 2" eyepeice options. I am pleased with the construction. Tried it out day viewing of the moon so far (cloudy tonight). Good fit on the 8SE. The SCT design provides the appropriate c...
GSO 1.25
GSO 1.25" 90-deg Mirror Star Diagonal for Refractors # GSST
4.0
Galileoscope+barlow lens=usable diagonal
I bought this and the GSO 2x shorty barlow and put the barlow lens element on the front of this to reach focus with a diagonal on a Galileoscope. Yes you can get 3 Galileoscopes for the combined price but I would assume anyone getting a Galileoscop...
GSO 2
GSO 2" 90-deg 99% Dielectric Mirror Diagonal for Refractors
5.0
GSO 2" 90 Degree Dielectric Diagnol
At night, I used it with conjunction with my premium eyepiece and with ES127AR and Meade 152AR. Now keep in mind that even the BEST diagonal will not give you a crisp, bright and free of aberration and loss of light if your scope is not collimated an...
GSO 2
GSO 2" 90-deg 99% Quartz Dielectric Mirror Diagonal for Refractors
5.0
Clear and Sharp!
I used this diagonal mirror for my 5 inch refractor (BORG 125SD). I fully enjoyed the star gazing by this mirror without any deficits such as los of brightness, decrease of contrast and artificial color.
GSO 2
GSO 2" 90-deg 99% Dielectric Mirror Diagonal for SCTs
4.0
Works for me!
I use this diagonal on a Celestron N8GPS and I found it to fit the bill quite nicely, allowing me the use of 2" eyepieces.
GSO 2
GSO 2" 90-deg 99% Dielectric Mirror Diagonal for SCTs
5.0
Incredible!
I was upgrading from the Celestron stock diagonal, and had never seen a "real" diagonal, so wasn't sure what to expect, except that a very well respected and highly experienced astronomer had suggested the GSO. When I opened the box, I was totally st...
GSO 2
GSO 2" 90-deg Mirror Diagonal for SCTs
5.0
Go 2", there's no excuses anymore
It used to be a dream to go to those great 2" eyepieces. Not anymore. For this price you can get those wide fields your SCT can give you and have money leftover for the eyepiece! OK, it is a bit on the heavy side and may upset your balance. It mi...
GSO 2
GSO 2" 90-deg 99% Dielectric Mirror Diagonal for SCTs
5.0
Bang for the buck
Love the fact that I can loosen the threaded ring, rotate the diagonal, and then lock it down secure. The SCT adapter brings the diagonal in close and cuts down on the increased focal length that a 2" visual back and a refractor diagonal would otherw...
GSO 2
GSO 2" 90-deg 99% Dielectric Mirror Diagonal for SCTs
5.0
High quality, low cost 2" diagonal
The GSO 2" mirror diagonal has a high quality 1/12 wave mirror, and a solid feeling CNC machine body. I've been using it for about 3 months now, and I can definitely recommend it as a 2" upgrade for anyone currently using 1.25" eyepieces. The diago...
William Optics 1.25
William Optics 1.25" 45-deg Erecting Prism Diagonal
5.0
William Optics 1.25" 45deg Erecting Prism
A fine quality prism. The care taken in the details is evident when you hold it in your hand. Nice smooth finish, large knurled thumbscrew, threading and flat black paint on the inside to cut reflections. This prism has a very slick design, and gr...
GSO 2
GSO 2" 90-deg 99% Dielectric Mirror Diagonal for Refractors
5.0
Very Nice 2" Diagonal
Excellent quality, excellent coatings on mirror. Machined tolerances are top notch. Highly recommended.
GSO 2
GSO 2" 90-deg 99% Dielectric Mirror Diagonal for SCTs
5.0
Best upgrade for your SCT
I replaced my 1.25 diagonal with this 2 inch GSO. I immediately noticed that the stars were brighter and crisper.This has been the best upgrade to my 8 inch SCT. I had to add a little more weight up front to balance the scope better. The diagonal is...
GSO 2
GSO 2" 90-deg 99% Quartz Dielectric Mirror Diagonal for SCTs
4.0
It works for me.
The only reason I gave it 4 stars instead of 5 is because of the threaded front has to be loosened in order to adjust the eyepiece closer to the viewer. Furthermore, when adjusting this diagonal it might cause damage to the threads on the SCT from co...