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what prism diagonal for refractor

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#1 dan_1984

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Posted 16 January 2021 - 04:57 AM

What prism diagonal you guys use?

I found the Baader Amici Prism

https://www.teleskop...al-quality.html



#2 Jethro7

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Posted 16 January 2021 - 06:29 AM

What prism diagonal you guys use?

I found the Baader Amici Prism

https://www.teleskop...al-quality.html

Hello Dan,

The only reason I would use a erecting prism is if I were terrestrial viewing. For astro viewing you will see the Roof line on bright objects and I find that annoying. I am so used to my views being reversed now and it does not bother me at all. I am a big fan of Baader diagonals and own several. In general if you are using  a Refractor that is slower than F/7  the prism diagonals are best and if your scope is faster, the mirror diagonals are best. This is due to the prisms shorter light path.  I use the Baader zeiss prism Diagonal for my  Altair 102ED F/1122 and a Baader BBHS Sitall mirror Diagonal on the faster scopes. Any way these  are the thoughts on this. How ever I have done side by side comparisons between these diagonals on different scopes and between the Baader Zeiss prism and the Baader BBHS Sitall mirror, I really can not see much of a difference except the prism diagonal takes several more minutes to reach temperature equilibrium.  The one thing that both of these diagonals do that is very noticable, they have a lot less light scatter over other diagonals I have owned. And that's one reason I am a fan. I imagine other premium diagonals will also exhibit similar characteristics. The Baader diagonals are very well built and their clicklock system is a pleasure to use.  In short if you dont mind that your views are reversed, save a few €'s and buy the Baader Zeiss Prism or the BBHS Sitall mirror prism. You will not be disapointed in either one.

 

HAPPY SKIES AND KEEP LOOKING UP Jethro


Edited by Jethro7, 16 January 2021 - 06:39 AM.

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#3 Simcal

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Posted 16 January 2021 - 06:45 AM

Here is a good read: https://www.cloudyni...omparison-r2877


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#4 dan_1984

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Posted 16 January 2021 - 07:03 AM

Hello Dan,

The only reason I would use a erecting prism is if I were terrestrial viewing. For astro viewing you will see the Roof line on bright objects and I find that annoying. I am so used to my views being reversed now and it does not bother me at all. I am a big fan of Baader diagonals and own several. In general if you are using  a Refractor that is slower than F/7  the prism diagonals are best and if your scope is faster, the mirror diagonals are best. This is due to the prisms shorter light path.  I use the Baader zeiss prism Diagonal for my  Altair 102ED F/1122 and a Baader BBHS Sitall mirror Diagonal on the faster scopes. Any way these  are the thoughts on this. How ever I have done side by side comparisons between these diagonals on different scopes and between the Baader Zeiss prism and the Baader BBHS Sitall mirror, I really can not see much of a difference except the prism diagonal takes several more minutes to reach temperature equilibrium.  The one thing that both of these diagonals do that is very noticable, they have a lot less light scatter over other diagonals I have owned. And that's one reason I am a fan. I imagine other premium diagonals will also exhibit similar characteristics. The Baader diagonals are very well built and their clicklock system is a pleasure to use.  In short if you dont mind that your views are reversed, save a few €'s and buy the . You will not be disapointed in either one.

 

HAPPY SKIES AND KEEP LOOKING UP Jethro

Thanks for the detailed reply. I will look into the Baader Zeiss Prism or the BBHS Sitall mirror prism



#5 Deadlake

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Posted 16 January 2021 - 08:40 AM

Hello Dan,

The only reason I would use a erecting prism is if I were terrestrial viewing. For astro viewing you will see the Roof line on bright objects and I find that annoying. I am so used to my views being reversed now and it does not bother me at all. I am a big fan of Baader diagonals and own several. In general if you are using  a Refractor that is slower than F/7  the prism diagonals are best and if your scope is faster, the mirror diagonals are best. This is due to the prisms shorter light path.  I use the Baader zeiss prism Diagonal for my  Altair 102ED F/1122 and a Baader BBHS Sitall mirror Diagonal on the faster scopes. Any way these  are the thoughts on this. How ever I have done side by side comparisons between these diagonals on different scopes and between the Baader Zeiss prism and the Baader BBHS Sitall mirror, I really can not see much of a difference except the prism diagonal takes several more minutes to reach temperature equilibrium.  The one thing that both of these diagonals do that is very noticable, they have a lot less light scatter over other diagonals I have owned. And that's one reason I am a fan. I imagine other premium diagonals will also exhibit similar characteristics. The Baader diagonals are very well built and their clicklock system is a pleasure to use.  In short if you dont mind that your views are reversed, save a few €'s and buy the Baader Zeiss Prism or the BBHS Sitall mirror prism. You will not be disapointed in either one.

 

HAPPY SKIES AND KEEP LOOKING UP Jethro

A lot of people end up with both of them, Baader Zeiss Prism or the BBHS Sitall mirror prism. 

The prism diagonal does take longer to cool however on planets I think it has better contrast then the Sitall version. 


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#6 Jethro7

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Posted 16 January 2021 - 08:59 AM

Thanks for the detailed reply. I will look into the Baader Zeiss Prism or the BBHS Sitall mirror prism

Hello Dan,

You wont be disapointed. In reality the difference between the two Baader diagonals is so slight that it does not mater for general viewing. In my opinion Baader makes one of the best diagonals that you can buy. Their quality is very high and very consistent. And even their less expensive "white" mirror star diagonal is a excellent performer. 

 

HAPPY SKIES TO YOU AND KEEP LOOKING UP Jethro



#7 Jeff B

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Posted 16 January 2021 - 10:15 AM

I have both the Baader Zeiss spec prism diagonal and the BBHS Sitall mirror.  Both are of very high optical quality.  Both have their purposes for me. 

 

The prism has the shorter light path which is useful when bino-viewing.  I use the prism diagonal almost exclusively for low power viewing with my refractors or high power viewing with my slower SCT's and Maks ( where the slower light cone is not disturbed by the refractive glass in the prism and the shorter optical path length helps keep the system close to its design intent when using bino-viewers). 

 

I use the BBHS Sitall diagonal for everything really when bino-viewing even low power, if I can get to focus with the viewer and no barlow element.

 

I've found, stacking of the diagonal prism with those in the viewer can lead to degradation of the color and spherical corrections of the system, which are quite visible at higher power, especially for systems that are F8 and faster.  For mono-vision (which I rarely use with the 1.25" format eyepiece), the prism diagonal does just fine really with F7 systems.  

 

That's my experience.

 

Jeff


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