skysurfer
08-04-2012, 07:15 PM
Two years ago I bought an Amici prism for my Televue Genesis due to the fact that the original Televue mirror diagonal produces mirror images which is not compatible with star cahrts.
It is a lot easier with an Amici, but at high power (> 100x) the image quality is not as good: more color errors and less contrast. I read in several forums that the Baader Amici prism is nearly as good as the mirror diagonal so I ordered one in this shop in Germany (http://www.teleskop-express.de/shop/product_info.php/language/en/info/p608_Baader-90--Amici-Prisma---beidseitig-T2-Anschluss.html). The shop is OK it has a very good reputation in Germany and Holland and I ordered products there earlier without a problem, so that is not the issue. It costs $260 ($224 + tube adapters not included). After reception I tested it.
With lack of clear skies I tested on a USAF1951 test chart (top center on test sheet) + Euro banknotes framed in a photo frame 20 meters away from the telescope.
That was a real disappointment. The Baader and the cheap $50 Amici were both less contrasty and had more color errors. (right two images), while the original Televue mirror diagonal is better. And the Baader was not better than the $50 cheapie. Used eyepiece: Vixen LV6 + barlow (180x) with the three mentioned star diagonals.
The figure '3' is 2cm high on the frame which corresponds to 3-4 arc minutes.
So I had the feeling I wasted $260 :mad2:
I will do a star test when there is a clear night.
It is a lot easier with an Amici, but at high power (> 100x) the image quality is not as good: more color errors and less contrast. I read in several forums that the Baader Amici prism is nearly as good as the mirror diagonal so I ordered one in this shop in Germany (http://www.teleskop-express.de/shop/product_info.php/language/en/info/p608_Baader-90--Amici-Prisma---beidseitig-T2-Anschluss.html). The shop is OK it has a very good reputation in Germany and Holland and I ordered products there earlier without a problem, so that is not the issue. It costs $260 ($224 + tube adapters not included). After reception I tested it.
With lack of clear skies I tested on a USAF1951 test chart (top center on test sheet) + Euro banknotes framed in a photo frame 20 meters away from the telescope.
That was a real disappointment. The Baader and the cheap $50 Amici were both less contrasty and had more color errors. (right two images), while the original Televue mirror diagonal is better. And the Baader was not better than the $50 cheapie. Used eyepiece: Vixen LV6 + barlow (180x) with the three mentioned star diagonals.
The figure '3' is 2cm high on the frame which corresponds to 3-4 arc minutes.
So I had the feeling I wasted $260 :mad2:
I will do a star test when there is a clear night.