20 replies to this topic

[gustave]

I want to take a break from 2” eyepieces and go with my 1.25 eyepieces. They are: TV 4.8 Nagler, TV 15 Wide Field, TV Nagler 26 Plossl, and a 40mm Celestron Plossl.  As well I have a William Optic binoviewer in which I use 24 Brandons.  The weak link is the diagonal that came with my 8Edge.  After shopping online I narrowed down to either the Tak or the Baader.
I’ve pretty much reduced my diagonal choices on what 1.25 diagonal to best match the above mentioned eyepieces.  They are: Baader Clicklock Dielectric, Tele Vue Everbrite, and the Takahashi 1.25" Prism.  Initially I wanted to go the TV but its reverse lateral image is not to my liking because it doesn’t match up with their recognizable images I’ve grown used to from years of observing and seeing in reference books.
I’m leaning toward the Baader, but there a temptation to go with the Tak given the brand’s excellent reputation and surprisingly competitive pricing.  One other concern I have is matching up to best support my bino’s weight.

Anyone care to weigh in?

 

Thanks for reading any thoughts you may have!

[cbowlsby]

All of these are good options.

The Takahashi prism is one of the sleeper options from what I’ve heard. When I did this I went the Baader route just because I like the convenience and security of the Clicklock mechanism and use it everywhere I can, even though it doesn’t always perfectly center the eyepiece.

[SeattleScott]

I like the Tak prism, but I don’t think I would love hanging a binoviewer off of it.

[eyespy]

Hi Gustave,

 

I have three of the TAK 1.25” prism diagonals and have not been concerned about their construction or stability even when using a binoviewer. They do have an ‘ABS’ type plastic body but in over four years, this has not been an issue. The nosepiece and eyepiece connections are both metal.

 

Doug…..

[Mike W]

I want to take a break from 2” eyepieces and go with my 1.25 eyepieces. They are: TV 4.8 Nagler, TV 15 Wide Field, TV Nagler 26 Plossl, and a 40mm Celestron Plossl.  As well I have a William Optic binoviewer in which I use 24 Brandons.  The weak link is the diagonal that came with my 8Edge.  After shopping online I narrowed down to either the Tak or the Baader.
I’ve pretty much reduced my diagonal choices on what 1.25 diagonal to best match the above mentioned eyepieces.  They are: Baader Clicklock Dielectric, Tele Vue Everbrite, and the Takahashi 1.25" Prism.  Initially I wanted to go the TV but its reverse lateral image is not to my liking because it doesn’t match up with their recognizable images I’ve grown used to from years of observing and seeing in reference books.
I’m leaning toward the Baader, but there a temptation to go with the Tak given the brand’s excellent reputation and surprisingly competitive pricing.  One other concern I have is matching up to best support my bino’s weight.

Anyone care to weigh in?

 

Thanks for reading any thoughts you may have!

Isn't the diagonal that came with the edge a mirror?

[c1ferrari]

I seriously considered the Baader T-2 / 90° Astro Amici-Prism with BBHS® coating to complement a BP Mark V BV, but will purchase the Baader 2" / 90° Astro Amici-Prism with BBHS® coating as there are several 2" eyepieces that have piqued my curiosity.  I may still purchase the former Astro Amici-Prism and have a dedicated 1.25" eyepiece/BV rig.

[GSwaim]

I have both Tak 1.25" 90° prism diagonal & the Baader 2" 90° prism diagonal. Both are quite excellent. I use Brandon eyepieces but also have a TV 55mm Plossl. I only do visual observations of sun, moon, and planets using APO refractors. 

 

The Tak prism may be the best for contrast & color on days/nights of seeing is best at the 4-5 range. Seeing at 4-5 is mostly rare however. Overall both are great and will depend upon telescope/eyepiece quality and seeing conditions. 

 

Just my opinion.

Edited by GSwaim, 24 April 2025 - 05:21 AM.

[Starman1]

I want to take a break from 2” eyepieces and go with my 1.25 eyepieces. They are TV 4.8 Nagler, TV 15 Wide Field, TV Nagler 26 Plossl, and a 40mm Celestron Plossl.  As well I have a William Optic binoviewer in which I use 24 Brandons.  The weak link is the diagonal that came with my 8Edge.  After shopping online, I narrowed down to either the Tak or the Baader.
I’ve pretty much reduced my diagonal choices on what 1.25 diagonal to best match the above-mentioned eyepieces.  They are: Baader Clicklock Dielectric, Tele Vue Everbrite, and the Takahashi 1.25" Prism.  Initially I wanted to go the TV but its reverse lateral image is not to my liking because it doesn’t match up with their recognizable images I’ve grown used to from years of observing and seeing in reference books.
I’m leaning toward the Baader, but there a temptation to go with the Tak given the brand’s excellent reputation and surprisingly competitive pricing.  One other concern I have is matching up to best support my bino’s weight.

Anyone care to weigh in?

 

Thanks for reading any thoughts you may have!

Uh, all the diagonals mentioned have the same image orientation--correct up/down and reversed left/right.

If you want a completely correct image, look for an Amici Prism diagonal.

Unfortunately, they have the "line" problem--because there is a split in the image, stars flare when crossing the center vertical line.

[CrazyPanda]

I can't speak highly enough about the Baader T2 Zeiss prism. Extremely sharp and high contrast. I used a T2 1.25" eyepiece holder, but I used a 2" nosepiece for a more secure connection and also to get the insides of the nosepiece as far away from the light path as possible for improved contrast.

 

It's robust enough to use with a binoviewer.

 

The weak plastic 1.25" Tak prism is not something I would add a binoviewer to.

[Mike W]

Uh, all the diagonals mentioned have the same image orientation--correct up/down and reversed left/right.

If you want a completely correct image, look for an Amici Prism diagonal.

Unfortunately, they have the "line" problem--because there is a split in the image, stars flare when crossing the center vertical line.

Exactly, what's this reversed lateral image with TV Everbrite about?

[cimar]

The Baader T2 prism is optically very good and mechanically versatile.

[Dobs O Fun]

Exactly, what's this reversed lateral image with TV Everbrite about?

 

He just said it here

 

Uh, all the diagonals mentioned have the same image orientation--correct up/down and reversed left/right.

If you want a completely correct image, look for an Amici Prism diagonal.

Unfortunately, they have the "line" problem--because there is a split in the image, stars flare when crossing the center vertical line.

 

 

More info from a previous post here.

Also here

 

If you have any other questions please PM me.

[Starman1]

Exactly, what's this reversed lateral image with TV Everbrite about?

All 90° diagonals yield images right side up and reversed left to right, whether prism or mirror.
Only by adding an additional reflection can the image be corrected left to right, which is what happens in an Amici prism.

[Mike W]

All 90° diagonals yield images right side up and reversed left to right, whether prism or mirror.
Only by adding an additional reflection can the image be corrected left to right, which is what happens in an Amici prism.

Thanks Don, I thought so but wasn't sure. 

[Bill Barlow]

Another option is the Vernon Scope 1.25" dielectric quartz diagonal.  It has at least1/20 wave smoothness but costs about $550.  I bought one to use with my A-P 92 Stowaway and it is excellent.  I also own the 1.25" Tak and Baader T2 prism diagonals which I use in my slower (f/7.5 to f/10) scopes.  

 

Bill

[mikeDnight]

 I use both the Tak and Baader/Zeiss BBHS prism's and find both to be excellent. I use a binoviewer and have no problem with either make holding the viewer firmly. The Baader has the advantages of interchangeable connections, for example, I sometimes use the Baader click-lock in 2" format with a reducer, or the Baader helical microfocuser 1.25". The Baader prism is oversized and if you chose the 2" click-lock and nose piece you could use a reducer for 1.25" while the prism will allow a 30mm 2" fit Ultraflat eyepiece to be used without vignetting should you choose to do so.

[kasprowy]

I have a TV-76 with the 2" everbrite. When I pop a 1.25" Tak prism (same object, scope, eyepiece) in it's place, the Tak shows objects noticeably brighter.

Edited by kasprowy, 23 April 2025 - 03:21 PM.

[Lagrange]

As far as I'm aware, the only Baader ClickLock Dielectric mirror is a 2" diagonal (I have one and it's great). You can use 1.25" eyepieces with it, but you need a 2"-1.25" adapter, and it's much larger and has a much longer optical path length than a 1.25" diagonal.

 

There are the T-2 Maxbright dielectric mirror diagonal, and the T-2 BBHS mirror diagonal which are both significantly smaller and can be configured to use a 1.25" nosepiece and accessories. Baader also make a couple of T-2 prism diagonals - a basic one and a more expensive Zeiss-spec model that can also have 1.25" accessories attached.

 

I've got the basic Baader T-2 Prism diagonal, and also the Tak 1.25" prism. I'm not sure I'd be able to see a difference between them in terms of image quality - they're both very good. The Tak prism is surprisingly solid and well made for something so lightweight, while the Baader is significantly heavier but more flexible in the ways that it can be configured.

 

The only real negative I've experienced with the Baader is that on a few occasions the nosepiece has loosened and partially unscrewed, resulting in the eyepiece and diagonal suddenly swinging down towards the ground. Thankfully the eyepiece didn't fall out but it gave me a fright each time.

Edited by Lagrange, 23 April 2025 - 07:36 PM.

[Starman1]

As far as I'm aware, the only Baader ClickLock Dielectric mirror is a 2" diagonal (I have one and it's great). You can use 1.25" eyepieces with it, but you need a 2"-1.25" adapter, and it's much larger and has a much longer optical path length than a 1.25" diagonal.

 

There are the T-2 Maxbright dielectric mirror diagonal, and the T-2 BBHS mirror diagonal which are both significantly smaller and can be configured to use a 1.25" nosepiece and accessories. Baader also make a couple of T-2 prism diagonals - a basic one and a more expensive Zeiss-spec model that can also have 1.25" accessories attached.

 

I've got the basic Baader T-2 Prism diagonal, and also the Tak 1.25" prism. I'm not sure I'd be able to see a difference between them in terms of image quality - they're both very good. The Tak prism is surprisingly solid and well made for something so lightweight, while the Baader is significantly heavier but more flexible in the ways that it can be configured.

 

The only real negative I've experienced with the Baader is that on a few occasions the nosepiece has loosened and partially unscrewed, resulting in the eyepiece and diagonal suddenly swinging down towards the ground. Thankfully the eyepiece didn't fall out but it gave me a fright each time.

To avoid that, always rotate the diagonal to the right.  The eyepiece weight will tighten the nosepiece, then.

[Lagrange]

To avoid that, always rotate the diagonal to the right.  The eyepiece weight will tighten the nosepiece, then.

 

That's really useful advice and it explains why the problem occurred in the first place. I'm left eye dominant so I was probably giving the eyepiece a slight lean to the left without realising it.

[mountain monk]

My two cents… I have a 2” TV Dielectric mirror, a 2” Baader Amici prism (the $700 job), and a Tak 1.25”. I use the Baader for both 2” and 1.25” eps up to about 200x, and the “line” does not bother me at all. Above 200x I switch to the Tak prism with my Tak DZ and it is flat out marvelous. I use the TV mirror with my NP-101. I have not worried about the weight of eps with the Tak. No problem.

 

Dark, clear, calm skies.

 

Jack