Baader T2 Zeiss Prism Diagonal

[John]

I'm considering purchasing one of these to use with my Tak FC100DL refractor.

I'm not that familiar with the Baader system approach so could anyone who has owned one advise which adapters etc I need to purchase with it to go on the scope and eyepiece sides. I'd like to end up with a diagonal that can handle 2" eyepieces but if sticking with the 1.25" format works better with this particular diagonal then I can live with that.

Also, can any one advise what the light path through one of these is and how that compares with a 2" mirror diagonal ?

Many thanks

[Dude_with_the_tube]

hi John,

i dont have the 1.25" version,but 2" zeiss prism,however,the principle is the same.Good thing about baader system is that you can swap/change adapters with ease.Remember that your prisms both sides have T2 thread.

In your case,optical path on your prism is 41mm,depending on what focuser you will use,you will need either 1.25" or 2" nose piece (T2).Baader stock codes :for 1.25" T2-14 2458105 or for 2"  T2-16 2408150,for the eye piece side,i would go for the click-lock system,and as you mentioned 2" eye pieces,you will need following:Baader 2" sct click-lock eye piece adapter.stock code:CLSC-2 2956220 and you will need Baader t2 to sct thread expanding ring stock code:T2-29a 2958242. this ring will add 1mm to your optical pass,but that shouldnt really affect anything.It is a fair bit of money but,i personally think it is worth it and i have enjoyed my prism immensely.As you guys said yourself,you are better off paying for a good quality once

as for comparison between mirror diagonals and prisms,i have done it and i found that prisms give sharper,more contrast image,specially for planetary observations.There is also (i am sure you have red it) quite a comprehensive comparison of mirror diagonal and prisms article done by William Paolini.here is the link:http://www.cloudynights.com/page/articles/cat/articles/mirror-vs-dielectric-vs-prism-diagonal-comparison-r2877

Good luck and clear skies.

 

[GavStar]

Hi John

i use the T2 set up for 2 inch eyepieces on my DL and it works very well. I got it from telescope express and find them very efficient and responsive.

here are the parts you need

diagonal base

http://www.teleskop-express.de/shop/product_info.php/info/p609_Baader---Zeiss-90--diagonal-prism---T2-thread-on-both-sides.html

2 inch adapter for telescope end

http://www.teleskop-express.de/shop/product_info.php/info/p481_Baader--16-Adapter-from-2--to-T2---2--focal-adapter.html

15mm extension between diagonal and 2 inch adapter so that you can install the sct clicklock on the other side (otherwise it doesn't fit)

http://www.teleskop-express.de/shop/product_info.php/info/p207_Baader-T2-Extension-Tube--25A--Length-15-mm.html

sct clicklock

http://www.teleskop-express.de/shop/product_info.php/info/p2427_Baader-2--Click-Lock-eyepiece-and-Adapter-holder-for-2inch-SC-thread.html

Sct expanding ring

http://www.teleskop-express.de/shop/product_info.php/info/p5300_Baader-Adapter-T2-female-to-SC-male-extension-ring.html

As I sometimes use 1.25mm eyepieces I also got this

http://www.teleskop-express.de/shop/product_info.php/info/p5817_Baader-CLICKLOCK-2--to-1-25--reducer-for-1-25-eyepieces-and-adapters---15-B.html

It should look a bit like the attached photo below.

Regarding light path the cloudynights review of diagonals shows t2 to be 67mm vs 100-110 for 2 inch mirror diagonals. 

Finally this seems the be the latest diagonal that some on the other forum like a lot which has all the attachments attached I think

http://www.teleskop-express.de/shop/product_info.php/info/p7951_Baader-2--BBHS-Sitall-Diagonal-Mirrorl-with-1-10-lambda-surface.html

[John]

Dude and Gavin - thanks very much !

 

[YKSE]

John,

Baader T2 prism diagonal has female T2 thread (42x0.75) on scope side, and male T2 thread on EP side.

There're many ways to connect it, what I can it:(you can look it in TS page by searching for baader number with prefix ba, such as ba2456095)

1. the simplest: A T2 to 2" barrel adapter, baader number 2408150 for scope side, and a 1.25" EP holder of clicklock 2956214, or 2458100, or none-clicklock types 2458125 or 2408190. You'll limited in using EPs with 1.25" barrel only.

2. 2" connection: Same 2408150 for scope side, 2956215 for 2" EPs (you can just unscrew the 1.25" nosepiece in this part, then connect the clickclamp part to diagonal via the T2 thread). you can use your 2" to 1.25" reducer here, but I would recommend 2956214, that little handle is well-thought engineer work, it makes so much easier to use in cold weather to secure the tightening and loosening.

You can of course add clickclamp on the focuser too, then you'll need find out thread size of your scope, and find appropriate part here:

http://www.teleskop-express.de/shop/index.php/cat/c126_Adapter-to-2-.html

As I see it, Baader has very consistent connection scheme, it looks this

From    2"     --->      SC thread or 2" barrel  or occationally M48(2" filter thread)      -->     T2 thread     -->       1.25" barrel

Therefore many of their adapters has dual threads in either side, and many parts are just combinations of single parts, a legoland for adults.

[John]

Thanks for that guidance Yong

[YKSE]

As to the lightpath, the T2 zeiss prism itself is 41mm according to Baader Maxbright binoviewer's manual page 7, the T2 to 2" barell adapter adds 2mm, 1.25" clickclamp(2956214) length 33mm, so it'll be 41+2+33=76mm in option 1. In 2" option with the same 1.25", the bigger clicklocks adds 47mm, while 2956214 adds 9mm instead of 33mm in direct connection, so it'll be 41+2+9+47=99mm.

I've seen 102mm lightpath mentioned for Televue's 2" mirror diagonal, not sure which one though.

[John]

Thanks all.

Adding the componants together to get a 2" fitting diagonal with the Baader Zeiss prism I get a total cost of around £300 - does that seem about right ?

[YKSE]

It seems right to me. By TS price, I get

SC to 2" barrel(2408150, €36), Zeiss T2 diagonal(2456095 €215), 2" clicklock (2956215 €89) and 2" to 1.25" clicklock reducer (2408150 €72), total €412 + postage.

[Dude_with_the_tube]

it is correct John,and this is purely the reason why instead of buying the 1.25" version of this prism,i went the opposite route and got the Zeiss 2" version from polish shop,worked out cheaper.i know these are on very short supply,but it might be worth checking and trying to source that one.Here is the link from Teleskop-Express:http://www.teleskop-express.de/shop/product_info.php/language/en/info/p612_Carl-Zeiss-2--Zenitprisma---im-CNC-Gehaeuse-von-Baader.html

[GavStar]

Not tempted by the new Baader BBHS silver diagonal then John? Similar price once you put all the bits on the t2 prism..

[John]

Thanks for the further suggestions folks.

I've gone for the Baader T2 Zeiss unit plus bits. It seemed to do well enough in Bill Paolini's group test.

 

 

[Stu]

3 minutes ago, John said:

Thanks for the further suggestions folks.

I've gone for the Baader T2 Zeiss unit plus bits. It seemed to do well enough in Bill Paolini's group test.

 

 

Good stuff John. I didn't contribute to the thread because you were getting great advice already! I've found these to be excellent, and allow the image to hold together at higher powers than a standard diagonal. Hope you enjoy it!

[surfindogg]

2 hours ago, Stu said:

Good stuff John. I didn't contribute to the thread because you were getting great advice already! I've found these to be excellent, and allow the image to hold together at higher powers than a standard diagonal. Hope you enjoy it!

This prism is my favourite solution. So glad I bought one. I have the smaller Zeiss prism diagonal with 1.25" and 2" nose pieces. The Baader 2" to 1.25" adapter has a T thread that allows you to attach it to the male T thread on the prism. All my 1.25" eyepieces fit without touching the face of the prism.

[cs1cjc]

I was unwilling to pay the price, hence the Takashi 1.25".

But then I have an APM rather than a TEC 140/7 and ES rather than  TV eyepieces...

[John]

2 hours ago, cs1cjc said:

I was unwilling to pay the price, hence the Takashi 1.25".

But then I have an APM rather than a TEC 140/7 and ES rather than  TV eyepieces...

For it's purchase price, the Tak 1.25" prism did excellently in Bill P's test too.

[Highburymark]

May be a bit late to help you John, but the best value retailer for Baader gear I've found is Microglobe in London - massive savings over a certain other London astro shop. I'm considering whether to go for the T2 or 2" Zeiss prism at the moment - for planets with my C8. Yong's thread from a couple of weeks ago provided very useful info on different Baader Lego pieces to buy - because they can get a little confusing

[Stu]

5 hours ago, Highburymark said:

May be a bit late to help you John, but the best value retailer for Baader gear I've found is Microglobe in London - massive savings over a certain other London astro shop. I'm considering whether to go for the T2 or 2" Zeiss prism at the moment - for planets with my C8. Yong's thread from a couple of weeks ago provided very useful info on different Baader Lego pieces to buy - because they can get a little confusing

Good tip Gavin. I just had a look on their site but couldn't see that they stocked or listed the prisms, are they special order items?

[Highburymark]

5 hours ago, Stu said:

Good tip Gavin. I just had a look on their site but couldn't see that they stocked or listed the prisms, are they special order items?

Stu - actually that post was from me not Gavin - the microglobe website is pretty poorly designed. You have to scroll through all the Baader gear (under 'scopes') to find what you want - but the T2 and 2" Zeiss prisms are on there. 

[Stu]

41 minutes ago, Highburymark said:

Stu - actually that post was from me not Gavin - the microglobe website is pretty poorly designed. You have to scroll through all the Baader gear (under 'scopes') to find what you want - but the T2 and 2" Zeiss prisms are on there. 

DOH! Sorry Mark!

Will have a look, I normally get this kind of stuff from TS but may look at these guys now.

Cheers

[John]

I bought mine from TS in the end. I've bought a few small bits and pieces from Microglobe and they have been OK but they did not have the components that I wanted for this purchase.

I probably ought not to say this but I wonder if Microglobe stock, perhaps, "grey imports" ?

 

 

 

[Highburymark]

1 hour ago, John said:

I bought mine from TS in the end. I've bought a few small bits and pieces from Microglobe and they have been OK but they did not have the components that I wanted for this purchase.

I probably ought not to say this but I wonder if Microglobe stock, perhaps, "grey imports" ?

 

 

 

Don't know about that John but I was in there on Friday and they were saying the Baader sales manager had just visited - think it's pukka, and the Zeiss T2 prism is only £155. Just not sure if I should get the 2" prism for my C8 - though that's £319.

[Highburymark]

On 2 June 2016 at 19:01, John said:

I'm considering purchasing one of these to use with my Tak FC100DL refractor.

I'm not that familiar with the Baader system approach so could anyone who has owned one advise which adapters etc I need to purchase with it to go on the scope and eyepiece sides. I'd like to end up with a diagonal that can handle 2" eyepieces but if sticking with the 1.25" format works better with this particular diagonal then I can live with that.

Also, can any one advise what the light path through one of these is and how that compares with a 2" mirror diagonal ?

Many thanks

 

John - once you've had a chance to road test the Baader prism, I'd be very interested to hear your initial thoughts, particularly on planetary glare/scatter. 

 

[John]

2 hours ago, Highburymark said:

 

John - once you've had a chance to road test the Baader prism, I'd be very interested to hear your initial thoughts, particularly on planetary glare/scatter. 

 

When I've reached some conclusions I'll post them. So far I've not noticed any negatives but the I don't feel the conditions have been anywhere near good enough to determine subtle differences between the Baader T2 Zeiss and my Astro Physics and Tele Vue Everbright mirror diagonals. Targets such as Mars and Saturn are not well placed for this either with the atmospherics creating so many issues

I'll get back to you on this around 2020 I guess !!

 

[Highburymark]

4 hours ago, John said:

When I've reached some conclusions I'll post them. So far I've not noticed any negatives but the I don't feel the conditions have been anywhere near good enough to determine subtle differences between the Baader T2 Zeiss and my Astro Physics and Tele Vue Everbright mirror diagonals. Targets such as Mars and Saturn are not well placed for this either with the atmospherics creating so many issues

I'll get back to you on this around 2020 I guess !!

 

Thanks John - conditions here have been pretty bad too.