Baader amici prism

[Tweedledee]

I am very impressed with my new Baader 90 degree 2" Amici prism diagonal on the ST120.

It looks really good with its high gloss black finish and feels like a very solid and quality accessory. The brass compression rings in the 2" and 1.25" adapter work perfectly with all my eyepieces which have various different types of safety undercut, no snagging. The brightness of transmission seems no different to my Meade UHTC mirror diagonal which actually feels of lesser quality construction. I'm sure in reality that there is a little less throughput due to the extra reflective surfaces within the prism, but the views are perfectly crisp and bright. There is no hint of any diffraction spike up to 67x in my 9mm ep. The design of these prisms means that it flips the image across a roof prism section and if the line of the apex is not made extremely accurately, it causes a single vertical diffraction spike. My Speers WALER zoom at the 12mm setting wouldn't quite come to focus with not enough in travel by probably 5mm, at its 8.5mm setting I reckon it needs about 10mm extra in travel. All my other eps are well accommodated by the available focus range. The zoom problem will be put right when I get my new focuser which has a lower profile than the standard one, and having 11:1 dual speed gearing should give an improvement in focusing the F5 light cone. This new focuser is a TS 3" version which will alleviate much of the vignetting produced by the original 2" draw tube when used with larger field stop eps.

The luxury of having a fully correct image is so nice. When panning around to find stuff, there is no need to do mental somersaults to suss out which way to star hop to your object whilst remembering or referring to a star map. With the altaz mount and no goto the correct image makes the telescope so much nicer and more natural to use.

 

I feel the money was definitely well spent.

[Doc]

Lovely report Pete and it does sound like a quality item, well it is Baader and they don't normally do bad quality.

 

I'm still in two minds if I should get one for my Christmas present or not. I don't really need one for deep space stuff, as to find this I just dial in the Alt/Az co-ords from Sky Safari. But for double stars and Lunar an amici would really be helpful.

 

Decisions decisions.