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Equipment Discussions >> Eyepieces

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leonard
scholastic sledgehammer
*****

Reged: 10/19/07

Loc: West Virginia
Re: UPDATE: Prism Diagonals new [Re: Eddgie]
      #6254373 - 12/15/13 12:06 PM

Hello ,

>>>> my primarly goal was to alert people that the T2 standard does not have the same prism as the T2 Zeiss, and just helping to know how to tell the difference. <<<<<

Good you pointed this out , no one wants to make a $129.00 mistake.
As always your experience an advice are warmly received .

Leonard


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leonard
scholastic sledgehammer
*****

Reged: 10/19/07

Loc: West Virginia
Re: UPDATE: Prism Diagonals new [Re: Roy McCoy]
      #6254376 - 12/15/13 12:08 PM

Hello


Thanks Roy


Leonard


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BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: UPDATE: Prism Diagonals new [Re: Eddgie]
      #6254527 - 12/15/13 01:37 PM Attachment (24 downloads)

Quote:

But optically, having owned both, and having compared them all to dielectric diagonals at f/10, I found no difference it quality.

Based on my experience with the f/7 refractor though, I would lean towards a mirror. I know that the prisms in the binoviewer caused pretty severe chromatic aberration at f/7.




Interesting how everyone's experiences seem to be so very different with prisms. For instance, in my initial tests on the Moon, CA was fairly little to my eye at f/6.25 in the APO. As the weeks roll on will try a variety of targets...so right now have not even stratched the surface of what needs to yet be done.

btw, here's a pic of the current batch. Like I said, some high quality mirror diaginals are on the way so we can have a premium to premium compare as well.

Back Row 2" (L to R): AT 2" Deilectric & Baader 2" Prism

Front Row 1.25" (L to R): Celestron 1980's Prism, AT Dielectric, Tak Prism, Baader T2 Zeiss Prism


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StarDust1
super member


Reged: 08/21/12

Re: UPDATE: Prism Diagonals new [Re: BillP]
      #6254616 - 12/15/13 02:48 PM

Bill, looking forward to your findings. I just ordered a Tak prism. I'm looking for a 2" mirror or prism. I'm not yet decided. It will be used with a TSA120 and FS60CB.

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SteveC
Post Laureate
*****

Reged: 06/15/06

Loc: Sunshine State & Ocean State
Re: UPDATE: Prism Diagonals new [Re: StarDust1]
      #6254848 - 12/15/13 05:12 PM

Bill,

This new project of yours is getting out of hand. Are you going to end up with about 9-10 diagonals? Switching out that many diagonals is a pain in the butt, even in warm weather.


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roadi
Pooh-Bah
*****

Reged: 08/18/07

Loc: Great Grey Spot "Denmark"
Re: UPDATE: Prism Diagonals new [Re: StarDust1]
      #6254892 - 12/15/13 05:33 PM

Quote:

Bill, looking forward to your findings. I just ordered a Tak prism. I'm looking for a 2" mirror or prism. I'm not yet decided. It will be used with a TSA120 and FS60CB.




Me too about the tests! I have the Tak prism too, I like it very much. To my eyes It handily beated two high quallity dielectric mirror diagonals on planetary contrast.
Rather enhanced mirror diagonal than dielectric


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JustaBoy
Post Laureate
*****

Reged: 06/19/12

Re: UPDATE: Prism Diagonals new [Re: roadi]
      #6254987 - 12/15/13 06:26 PM

I seem to remember reading in one of the old telescope making books, that for the most critical observations a Diagonal is never used...

But then men were a lot tougher back then, or at least in My Case, a Lot Younger! .


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BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: UPDATE: Prism Diagonals new [Re: SteveC]
      #6255035 - 12/15/13 07:00 PM

Quote:

Bill,

This new project of yours is getting out of hand. Are you going to end up with about 9-10 diagonals? Switching out that many diagonals is a pain in the butt, even in warm weather.




You are quite right Not an easy or fast process switching diagonals. Any observations relative to sharpness will require seeing that does not fluctuate too much...which means...time waiting that out.

Anyway, was able to conduct a on-axis CA test tonight using the f/8 TSA-102. Conducted as in the previous test using the bright limb of the Moon, basically all the diagonals performed nicely with no hints of color, even racking focus in and out a little. So while the fast f/6.25 showed varying degreees of none to slightly more than minimal color, all showed none at f/8.


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SteveC
Post Laureate
*****

Reged: 06/15/06

Loc: Sunshine State & Ocean State
Re: UPDATE: Prism Diagonals new [Re: BillP]
      #6255404 - 12/15/13 10:37 PM

Quote:

Quote:

Bill,

This new project of yours is getting out of hand. Are you going to end up with about 9-10 diagonals? Switching out that many diagonals is a pain in the butt, even in warm weather.




You are quite right Not an easy or fast process switching diagonals. Any observations relative to sharpness will require seeing that does not fluctuate too much...which means...time waiting that out.

Anyway, was able to conduct a on-axis CA test tonight using the f/8 TSA-102. Conducted as in the previous test using the bright limb of the Moon, basically all the diagonals performed nicely with no hints of color, even racking focus in and out a little. So while the fast f/6.25 showed varying degreees of none to slightly more than minimal color, all showed none at f/8.




That's great!!
Basically I don't have a real response, this is just a gratuitous post in order to get to 3000 posts and receive the free CN T-shirt that everyone gets for reaching the milestone.

Edited by SteveC (12/15/13 10:41 PM)


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Roy McCoy
Pooh-Bah
*****

Reged: 10/13/05

Loc: Glendale, AZ
Re: UPDATE: Prism Diagonals new [Re: SteveC]
      #6255437 - 12/15/13 11:00 PM

Woohoo!
Only fourteen more years and I'll get one too!


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JustaBoy
Post Laureate
*****

Reged: 06/19/12

Re: UPDATE: Prism Diagonals new [Re: Roy McCoy]
      #6255462 - 12/15/13 11:23 PM

3000 CONGRATS STEVE!!!






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roadi
Pooh-Bah
*****

Reged: 08/18/07

Loc: Great Grey Spot "Denmark"
Re: UPDATE: Prism Diagonals new [Re: JustaBoy]
      #6255644 - 12/16/13 03:35 AM

Quote:

I seem to remember reading in one of the old telescope making books, that for the most critical observations a Diagonal is never used...

But then men were a lot tougher back then, or at least in My Case, a Lot Younger! .




I have experienced this too many times, but do prefer relaxed viewing with diagonals and if so I found the least differences were between the prism/enhanced mirror vs straight through.


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BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: UPDATE: Prism Diagonals new [Re: SteveC]
      #6255785 - 12/16/13 08:16 AM

I never got a T-Shirt at 3000, or any other number

And now that Steve is a part of the 300 ... I mean 3000, then his t-shirt should have the appropriate image -- Link.

Edited by BillP (12/16/13 09:18 AM)


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ThomasWos
super member


Reged: 02/10/07

Loc: Bellingham WA
Re: UPDATE: Prism Diagonals new [Re: Don Taylor]
      #6259062 - 12/17/13 09:56 PM

Quote:

I'm looking to get a Baader T2-01C as well and understood that it does not have a Zeiss prism - but the short optical path solves some unique issues for my application.

BTW - it is also available from Agena (along with the other Baader diagonals)- although neither Apline nor Agena have any in stock at this time.




After waiting over a year, finally been able to order the T2 Baader prism diagonal from Telescope Service in Germany.

New Baader #BA2456005, I believe replaces T2-01C.

Arrives this week via DHL/USPS.


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etsleds
sage
*****

Reged: 11/14/09

Re: UPDATE: Prism Diagonals new [Re: ThomasWos]
      #6259147 - 12/17/13 10:40 PM

I've been pretty impressed with the large diagonal prism that's built into the Tak turrets, perhaps another one to add to the comparo?

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Don Taylor
professor emeritus


Reged: 07/12/09

Loc: South TEXAS
Re: UPDATE: Prism Diagonals new [Re: ThomasWos]
      #6259305 - 12/18/13 12:48 AM

Quote:

Quote:

I'm looking to get a Baader T2-01C as well and understood that it does not have a Zeiss prism - but the short optical path solves some unique issues for my application.

BTW - it is also available from Agena (along with the other Baader diagonals)- although neither Apline nor Agena have any in stock at this time.




After waiting over a year, finally been able to order the T2 Baader prism diagonal from Telescope Service in Germany.

New Baader #BA2456005, I believe replaces T2-01C.

Arrives this week via DHL/USPS.




Yes! This is the same part number shown on the agena site - also available with nosepiece and eyepiece holder as 2456005K

Agena says coming soon!

Alpine Astro told me they expected to receive these late November - but has not. I'm hoping soon. Otherwise I'll be ordering one from TS as well. Thanks!!!


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Don Taylor
professor emeritus


Reged: 07/12/09

Loc: South TEXAS
Re: UPDATE: Prism Diagonals new [Re: Don Taylor]
      #6262775 - 12/19/13 10:47 PM

Agena has both versions of the T2-01C instock - well, I guess I got the last 245006K.

Looking forward to trying in my smaller refractors.


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BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: UPDATE: Prism Diagonals new [Re: BillP]
      #6298925 - 01/07/14 09:37 PM

FYI, just received the last two loaner diagonals, so will be doing a round of tests then publish a diagonal shootout article.

- Celestron 1.25" 1980s Prism

- Astro Tech 1.25" 99% Reflective 1/10th Wave Substrate Dielectric

- Takahashi 1.25" 100% Reflective Prism

- Tele Vue 1.25" Everbrite Dielectric 1/10th Wave

- Baader Zeiss 1.25" T-2 Prism

- Astro Tech 2" 99% Reflective 1/10th Wave Substrate Dielectric

- Baader 2" Prism

- Takahashi 2" Enhanced Aluminum Pyrex Mirror 1/10th Wave


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george tatsis
professor emeritus
*****

Reged: 11/20/08

Loc: Flushing, NY - Europe
Re: UPDATE: Prism Diagonals new [Re: BillP]
      #6299472 - 01/08/14 07:56 AM



George


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Fomalhaut
scholastic sledgehammer


Reged: 08/16/08

Loc: Switzerland
Re: UPDATE: Prism Diagonals new [Re: BillP]
      #6299516 - 01/08/14 08:36 AM

Bill, since you're including two Baader prism diagonals in your testings I would personally have appreciated the inclusion of also one Baader (same brand!) Maxbright mirror diagonal with 140 EBC-layers. Or maybe also an AP Maxbright with 47 EBC-layers to see if there occurs any difference... Just because these two seem reputed to be the very best (AP in your country, Baader in Europe). And in order that nobody will be able to say that the best prisms topped the second best mirrors only...
Nevertheless appreciating your work.
Chris


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