Re: amici diagonal


Sep 5, 2003

 


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#18636 Sep 5, 2003

Whoops -- I am late to this discussion, so please forgive if this is

redundant. What is the best choice of amici prism for use with a

Traveler. Intended use is mostly (90% plus) for terrestrial viewing. I

noted the new Williams 2-inch amici, but they are unsure whether it

works with the Traveler...

-p



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#18638 Sep 6, 2003

the william optics work on the traveller, but clear aperture is no more than

on the Baader T2 amici and the Baader have for shure the better optics

Markus ----- Original Message -----

From: "Paul Saffo" psaffo@...>

To: ap-ug@yahoogroups.com>

Sent: Saturday, September 06, 2003 2:39 AM

Subject: [ap-ug] amici diagonal





> Whoops -- I am late to this discussion, so please forgive if this is

> redundant. What is the best choice of amici prism for use with a

> Traveler. Intended use is mostly (90% plus) for terrestrial viewing. I

> noted the new Williams 2-inch amici, but they are unsure whether it

> works with the Traveler...

> -p

>

>

>

> To UNSUBSCRIBE, or for general information on the ap-ug list

> see groups.yahoo.com/group/ap-ug

>

> Your use of Yahoo! Groups is subject to docs.yahoo.com/info/terms/

>

>



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#18641 Sep 6, 2003

Paul asks:

> What is the best choice of amici prism for use with a

> Traveler. Intended use is mostly (90% plus) terrestrial.



> I noted the new Williams 2-inch amici, but they are unsure whether

> it works with the Traveler...



Hi Paul -



Here's my eight cents on one of my favorite subjects...



The Williams prism is by far the best choice for your intended

purpose. I've been using one with a Traveler for the past year and I

was using a similar unit for years before that.



For me, the issue is the 45. viewing angle, not obtaining an image

that's correct left-to-right. I've never understood birders who

think a mirror-reversed view is inadequate. (I won't go so far as

Sue French, who, according to Alan, doesn't even care if the ducks

are swimming upside down. I mean, there IS a certain aesthetic

involved. (Fun suggestion for Mr. French - flip the TVs in the house

over and see if she's fine with that, too.))



The ergonomic benefits of a 45. view are the true selling point for

me. Easier on the neck; easier to share; lower, better balanced

scope. The optical trade-offs are minimal if you stick to the

magnification range typically employed by traditional spotting

scopes. If I go above 50x I always switch to the 90. mirror diagonal

as high-power targets are likely to be stationary anyway.



It's true that the clear aperture of the Williams prism is about 31

mm but any vignetting that results from use of eyepieces with wider

field stops such as a 35 panoptic is hardly objectionable - more to

the point, how useful is 17x for terrestrial use? I seldom use

anything longer than a 22 nagler during the daytime. It gives me 28x

with a 3. field and has a field stop diameter of... 31 millimeters.



The Baader 90. prism might very well be a bit better optically but I

still doubt it could be free of annoying aberrations at planetary

magnifications and I would find it about as useful tits on a bull.

What i COULD use would be a good 2" PORRO prism that would provide a

quality straight-thru view up into middle-high terrestrial

magnifications. Anyone know of such a beast?



Rob Hunt



By the way - get yourself a Wimberley mount.


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