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Questions about Baader Zeiss Prism diagonal

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#1 Steve Daniel

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Posted 29 October 2020 - 08:46 AM

Hello all, I have this diagonal:  Baader 2" Clicklock 90° Star Diagonal with Carl Zeiss Spec Prism # PRISM-2Z 2456117.

 

Last night I noticed the prism seems to slide slightly left to right (90 degrees to the optical path), maybe 1mm, enough to cause a knock as the prism slides left to right when handling.  There is no movement I can detect up and down or back and forth (along the optical path) that I can detect. I don't notice any image degradation, still great viewing, stars are quite pinpoint.

 

Questions for the wise here:

- is this a common occurrence with prism diagonals?

- should I open this up and tighten things just enough to stop the sliding?

- what is the alignment procedure for this diagonal should I find I need to align it?

- should I just send it somewhere for service?

- should I leave it as is and just keep using it?

 

Thanks all.



#2 wrvond

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Posted 29 October 2020 - 09:22 AM

It's worthless. I'll give you $10.00 to cover shipping and you can send it to me.  ;)

 

Seriously, a prism that is free to rattle around is at risk of damage, and you don't want to damage an out of production Zeiss Spec prism!

 

To collimate any diagonal, I use a flat mirror and my Hotech laser. Insert the Hotech into the eyepiece barrel and turn it on, hold the telescope barrel flat on the mirror and observe the return laser dot on the grid. Adjust the mirror/prism until the dot is centered on the grid.



#3 sanbai

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Posted 29 October 2020 - 12:31 PM

I'll check that tonight, but I don't recall anything like this in my unit. However, it's not the first time I hear something similar in CN. Give a call to Alpine (if bought in the US) or Baader


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#4 Steeveaux

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Posted 29 October 2020 - 12:40 PM

I'd be inclined to leave it alone.  Lots of thermal expansion thought goes into the design.  It needs to be loose enough to stay loose and tight enough to stay in place.  If it is too tight, the figure might suffer--intolerable.  If it is too loose, the chunk of glass might rattle a little--I can handle that.

 

I've got that prism, btw.  Can't wait to get home and shake it!

 

Steve



#5 Steve Daniel

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Posted 29 October 2020 - 02:49 PM

Thanks all for the ideas.  @wrvond, I'll be keeping it lol.gif  At this point, I'm inclined to leave it alone, at least unless I notice a visual problem, or it seems to be getting more loose over time.


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#6 daniel_h

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Posted 29 October 2020 - 04:19 PM

it won’t get damaged, if you get 2 small pieces of foam with adhesive, or some 3m tape, open it up and place it in the corners of the prism to stop it rattling around, obviously not in the middle of the prism surface, place near edge



#7 Jeff Bennett

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Posted 29 October 2020 - 05:08 PM

I recently obtained the same diagonal, a used unit that seems to be in perfect shape.  I gave it a very light shake side to side and did hear a slight rattle suggesting some play around the prism.  But the diagonal seems to be well collimated, both before and after the shake.  I have been comparing to an AP MaxBright and have been happy so far.

 

I would be very curious to hear what Baader has to say; I have read other accounts of this and suspect that it is a design feature.


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#8 mtminnesota

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Posted 29 October 2020 - 05:23 PM

I may be wrong, but I can't imagine why a manufacturer would want any optical component sliding around inside its housing.  I bought one of those diagonals from Baader and the prism slid around at least 1/8" when it was tilted.  They gave me a replacement, which was made correctly.  These cases show that all is not well in the plant in China that makes these things.  


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#9 wrvond

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Posted 29 October 2020 - 06:56 PM

While my Baader prism is not a Ziess spec, it is a 2" BBHS with ClickLock #2456117.

It does not rattle at all.



#10 sanbai

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Posted 29 October 2020 - 09:11 PM

While my Baader prism is not a Ziess spec, it is a 2" BBHS with ClickLock #2456117.
It does not rattle at all.

It's the same item. I've checked mine and don't feel any play at all.

Edited by sanbai, 29 October 2020 - 09:12 PM.


#11 Steve Daniel

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Posted 29 October 2020 - 09:13 PM

Thanks, Sanbai, appreciate you checking.


Edited by Steve Daniel, 30 October 2020 - 12:30 PM.


#12 RichA

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Posted 29 October 2020 - 11:29 PM

Hello all, I have this diagonal:  Baader 2" Clicklock 90° Star Diagonal with Carl Zeiss Spec Prism # PRISM-2Z 2456117.

 

Last night I noticed the prism seems to slide slightly left to right (90 degrees to the optical path), maybe 1mm, enough to cause a knock as the prism slides left to right when handling.  There is no movement I can detect up and down or back and forth (along the optical path) that I can detect. I don't notice any image degradation, still great viewing, stars are quite pinpoint.

 

Questions for the wise here:

- is this a common occurrence with prism diagonals?

- should I open this up and tighten things just enough to stop the sliding?

- what is the alignment procedure for this diagonal should I find I need to align it?

- should I just send it somewhere for service?

- should I leave it as is and just keep using it?

 

Thanks all.

Seen from many microscope bino heads, it's easy to chip a prism that is loose.  Shimming it with some kind of semi-compressible material is a solution.


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#13 Steeveaux

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Posted 30 October 2020 - 07:15 AM

Mine "rattles" very gently.  It is almost imperceptible. It is obvious that it is not tight though.



#14 Steve Daniel

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Posted 30 October 2020 - 03:31 PM

Sent an email to Baader; we'll see what they say...



#15 BillP

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Posted 01 November 2020 - 10:54 PM

Thanks all for the ideas.  @wrvond, I'll be keeping it lol.gif  At this point, I'm inclined to leave it alone, at least unless I notice a visual problem, or it seems to be getting more loose over time.

It will not hurt to call Alpine Astro or email them and ask what can be done.  Bob Luffel is a great guy and will help you out.  The optics in any equipment should ever rattle.  I've had my Zeiss prism for 5 years now and it makes no noises.


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#16 Scott99

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Posted 02 November 2020 - 12:49 PM

The optics in any equipment should ever rattle.  I've had my Zeiss prism for 5 years now and it makes no noises.

agree, especially the "premium" expensive stuff....send this one back - I've had 4 Baader diagonals and none rattled.  I'm sure they'll be happy to replace it for you.


Edited by Scott99, 02 November 2020 - 12:50 PM.



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