What is the main advantage of the Baader 90° Astro-Grade Amici Prism over a standard star diagonal?
The primary advantage is its fully corrected image orientation. A standard star diagonal provides an image that is upright but mirror-reversed (left and right are swapped). The Baader Amici Prism corrects both axes, so the view is upright and not reversed, perfectly matching what you see with your naked eye or on a star chart. Baader makes it for astronomical observation at high magnification.
What is included?
The 2" Astro Amici prism with 2" ClickLock clamp and 2" nosepiece. Baader ships its 2" diagonals without a 1.25" reducer; the ClickLock 2" to 1.25" reducer (#2956214) is available separately.
What does the "Astro-Grade" designation mean for this Baader Amici Prism?
The prism is astro quality, manufactured to Zeiss standard, and suited for astronomical observation at high magnification because of a precise angle of the roof surfaces. Baader's terrestrial Amici prisms, by contrast, are made for lower magnifications up to about 60-100x.
Can the prism be attached to a Baader Diamond Steeltrack focuser?
Yes. Baader 2" star diagonals can be attached directly to the end of a Diamond Steeltrack focuser through the S58 dovetail, in place of the focuser's 2" eyepiece clamp, which extends the available backfocus for long accessories such as binoviewers; the 2" Astro Amici prism has the same S58 dovetail.
How does the 2-inch ClickLock clamp work on this Baader prism?
A 20° turn of the rotary lever with light pressure clamps the accessory, which is held on three sides like a quick-action chuck and aligned parallel to the optical axis; a ratchet indicates acoustically and haptically whether the clamp is open or closed, and the massive tension ring holds accessories without scratches.
Can filters be used with the Astro Amici prism?
The 2" Safety-Kerf nosepiece (#2408156) has a standard 2" (M48) filter thread on the telescope side and a second M48 female thread inside, so a 2" filter can be mounted permanently inside the body, for example as dust protection or to keep a deep-sky filter in the light path. The demands on a filter's optical quality rise the further it sits from the focal point.
Can the prism be fitted with an M68 connection?
Baader's M55a/M68i adapter (#2458234) can give all 2" Baader star diagonals a female M68 thread on the eyepiece side, for example so that the ClickLock can be replaced by an M68 quick changer. The M55a/M68a (Zeiss) adapter (#2956110) converts the 2" BBHS diagonals to the Zeiss system with an M68 male thread on the telescope side. Removing the black threaded ring to expose the M55 thread needs the adjustable face spanner (#2450062).
What are the benefits of the BBHS® coating on the Baader Amici Prism?
BBHS gives 98-99% reflection from slightly above 390nm to 2000nm. On this prism the coating is sealed and permanently protected against ageing, and the silver coating on the glass protects against dirt on the reflective surface.
How do I connect the Baader 90° Amici Prism directly to my Schmidt-Cassegrain telescope?
You can achieve a direct, threaded connection by unscrewing the 2" nosepiece from the telescope side of the prism. This will expose a female 2" SCT thread. This attaches it directly to a Schmidt-Cassegrain and reduces the overall length. The ClickLock usually has to come off first (six small screws) so it does not hit the focusing knob, and the separately available 2" Locking Ring (#2458270) fixes the diagonal in any rotational position.
How much does the Baader 2" Amici Prism weigh?
The net weight is 0.66 kg. Check your focuser's load rating and the telescope's balance; the prism can also be screwed onto a Schmidt-Cassegrain thread or attached to a Diamond Steeltrack focuser through the S58 dovetail.
