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New Baader/Zeiss T2 prism - Correct Image!


iPeace

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1 minute ago, John said:

The picture looks just like the one I have and use with my Tak 100. Mine shows an upright image but left & right reversed :icon_scratch:

Maybe there is more than one version that looks the same ?

There is indeed. Yours will have a different part number:

http://www.baader-planetarium.com/en/accessories/optical-accessories/prism-and-mirror-star-diagonals/baader-t-2-stardiagonal-(zeiss)-prism-with-bbhs-r-coating-(t-2-part-01b).html

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Ah, yes I can see there are slight differences in the casing design. The one you have uses an amici prism design and has a clear aperture of 31mm wheras mine uses a standard prism with a 35mm clear aperture.

Baader stuff is great but it can be confusing working out which componant is which !

It will be interesting to see if you witness the amici spike effect.

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1 minute ago, John said:

Ah, yes I can see there are slight differences in the casing design. The one you have uses an amici prism design and has a clear aperture of 31mm wheras mine uses a standard prism with a 35mm clear aperture.

Baader stuff is great but it can be confusing working out which componant is which !

It will be interesting to see if you witness the amici spike effect.

I suppose I'll know it if I see it?

:confused4:

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4 minutes ago, iPeace said:

I suppose I'll know it if I see it?

:confused4:

I think Baader have really minimised the effect with this product but my understanding is that it's inevitable to some degree. It's probably only going to show on the brightest of objects and then you may have to look for it. If the fully corrected image is a priority then this is probably as good as it will get from any manufacturer currently and I can fully see why you went for it.

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Anyway, I've got a herd of diagonals to compare this season.

There's the 2" TeleVue Everbrite Dielectric I can use as a baseline.

Then there's the 2" Baader Zeiss prism, standard reverse-image (mine was sold as produced to Zeiss standard, it doesn't seem to be described the same way now):

http://www.baader-planetarium.com/en/accessories/optical-accessories/prism-and-mirror-star-diagonals/baader-2"-bbhs-r-prism-star-diagonal-prism-with-2"-clicklock-clamp.html

Then there's the 2" Baader Amici prism, explicitly not of astro quality, but I have used it for astro anyway to create a uber-RACI:

http://www.baader-planetarium.com/en/accessories/optical-accessories/prism-and-mirror-star-diagonals/baader-2"-amici-erecting-prism-90°-with-2"-holder-and-2"-sleeve.html

And finally, my most recent, the T-2 Baader Zeiss astro amici prism:

http://www.baader-planetarium.com/en/accessories/optical-accessories/prism-and-mirror-star-diagonals/baader-t-2--90°-baader-roof-prism-with-bbhs-r-coating-(t-2-part-02).html

Any specific ideas on how to compare the performance of these are most welcome.

:happy11:

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5 minutes ago, John said:

I think Baader have really minimised the effect with this product but my understanding is that it's inevitable to some degree. It's probably only going to show on the brightest of objects and then you may have to look for it. If the fully corrected image is a priority then this is probably as good as it will get from any manufacturer currently and I can fully see why you went for it.

Like on Venus? Is it something that would have really jumped out, grabbed me by my whatever, and said: I'm why people don't buy amici prisms?

:icon_biggrin:

As per my report, the worst I saw at max. mag. was a definite rainbow fringe either side of perfect focus.

Edited by iPeace
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My diagonal herd comprises:

- 2" Tele Vue Everbright Enhanced Aluminum (on the ED120)

- As above but the dielectric version (on the Vixen ED102SS)

- 2" Astro Physics MaxBright Dielectric (on the LZOS 130 F/9)

- Baader T2 Zeiss Prism (on the Tak FC100 F/9)

I've given up trying to see any differences between them to be honest with you. There probably are some but nothing obvious to my eye :smiley:

If I had to live with just one I think it would be the Astro Physics but thats probably mostly because I've always wanted to own something by AP and the diagonal is all that I've had, thus far !

 

Edited by John
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19 hours ago, Timebandit said:

 

Yes I know there is no upside down in outer space ?, but give

20 hours ago, John said:

I'll take the optical quality every time and handle the (for me minor) issue of the reversed left and right. I've sort of got used to it over the 35 years I've been using scopes with diagonals. I'd probably get confused if I changed to a fully corrected image in the main scope !

Also I can't see the point in using a top end objective and eyepiece and having something in between that is less than that :icon_scratch:

 

 

 

me quality of image every day, and this is especially true on planetary and lunar observing, where you are trying to pick out as much fine detail as possible .

The diagonal to many seems to be a bit of a infill and IMO there is no point putting effort and money into a great scope and eyepiece and then put a so so diagonal into link . As the quality of image is only as good as the weakest link in the optical chain. This is why I picked up a televues diagonal when one came up used to try and get a optical chain that was IMO equal in quality to each part in the link. Give me optical quality every time IMO. 

In time I may come around to this view - getting a quality refractor at some point and getting more experience under my belt to appreciate the extra quality could swing it.

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  • 1 month later...

I like this diagonal so much that I got another one...but had to return it. When observing a bright object (Jupiter), a pale smudge of light could be seen running horizontally through the object from one side of the image to another. This is clearly not supposed to happen... :duckie:

However, I've ordered another one to replace it, will give it a few more tries if necessary to get another good one.  :happy9:

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29 minutes ago, iPeace said:

I like this diagonal so much that I got another one...but had to return it. When observing a bright object (Jupiter), a pale smudge of light could be seen running horizontally through the object from one side of the image to another. This is clearly not supposed to happen... :duckie:

However, I've ordered another one to replace it, will give it a few more tries if necessary to get another good one.  :happy9:

Sounds like diffraction from a prism edge :icon_scratch:

Hope the next one is good :smiley:

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That 90 Degree erecting prism is tres expensive but what I've considered recently is ....

In the HIFI world the correct chain of importance is 

1. Source .... CD player or Turntable 

2. Amplifier 

3. Speakers 

So it stands that in the Astronomy world the correct chain of importance would be

1. Telescope / Optics

2. Diagonal

3. Eyepiece 

Now many will happily spend hundreds on an EP but only around £100 on a diagonal 

I suggest that this may be an error as the diagonal in the chain is actually more important than the EP

Brian 

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On 04/07/2017 at 02:08, John said:

Sounds like diffraction from a prism edge :icon_scratch:

Hope the next one is good :smiley:

Replacement is in and we will see if we can dodge the clouds to check it out after dark. Will report.

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Unfortunately, another dud. Back it goes. This one comes directly from Baader, so I will engage with them to try and find out what's going on.

I already have one that's perfect and would very much like another. Hope my good one is not the exception.

To be continued.

:(

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7 hours ago, iPeace said:

Unfortunately, another dud. Back it goes. This one comes directly from Baader, so I will engage with them to try and find out what's going on.

I already have one that's perfect and would very much like another. Hope my good one is not the exception.

To be continued.

:(

Shame.

How are you defining dud? Is this perhaps just the reason Amici prisms are not so suitable for astro?

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5 hours ago, Stu said:

Shame.

How are you defining dud? Is this perhaps just the reason Amici prisms are not so suitable for astro?

Good point. My use of 'dud' here is to designate these specimens as inferior to my first one, which is, to my eyes, perfect and which set my expectations.

I have since been in contact with Baader, and they have echoed your thoughts by stating their suspicion that what I've been seeing in the two specimens I have returned is within their tolerances, something only noticeable by the keenest of observers. Fair enough. I'm fully prepared to accept this is the case - and if I didn't know otherwise, due to having acquired one which is absolutely excellent, that would be the end of it. I would either live with it, or go back to reverse-image observing, as there are no high-quality, correct-image alternatives I know of (Baader's own 2" ClickLock version has been out of stock for some time now).

As it is, I've been spoilt into expecting - now turned down a notch to hoping - another excellent specimen is to be had. Baader have promised to compare the one most recently returned to their current stock and to make absolutely sure the next one delivered is as good as it gets.

Excellent service; cannot ask for more. Worst case, I have my excellent specimen to keep and cherish and will have to compromise when it comes to any others. Hardly worth mentioning in the ledger of problems.

For the moment, I will hope that another excellent one is to be found.

To be continued.

:happy11:

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26 minutes ago, iPeace said:

Good point. My use of 'dud' here is to designate these specimens as inferior to my first one, which is, to my eyes, perfect and which set my expectations.

I have since been in contact with Baader, and they have echoed your thoughts by stating their suspicion that what I've been seeing in the two specimens I have returned is within their tolerances, something only noticeable by the keenest of observers. Fair enough. I'm fully prepared to accept this is the case - and if I didn't know otherwise, due to having acquired one which is absolutely excellent, that would be the end of it. I would either live with it, or go back to reverse-image observing, as there are no high-quality, correct-image alternatives I know of (Baader's own 2" ClickLock version has been out of stock for some time now).

As it is, I've been spoilt into expecting - now turned down a notch to hoping - another excellent specimen is to be had. Baader have promised to compare the one most recently returned to their current stock and to make absolutely sure the next one delivered is as good as it gets.

Excellent service; cannot ask for more. Worst case, I have my excellent specimen to keep and cherish and will have to compromise when it comes to any others. Hardly worth mentioning in the ledger of problems.

For the moment, I will hope that another excellent one is to be found.

To be continued.

:happy11:

Interesting! So you have one Zeiss (?) Amici Prism which you are totally happy with but the others have shown image artifacts you aren't happy with?

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Just now, Stu said:

Interesting! So you have one Zeiss (?) Amici Prism which you are totally happy with but the others have shown image artifacts you aren't happy with?

Exactly! I concur with your qualification of 'interesting'. As stated, Baader are on top of this and working to get me another excellent one.

:happy11:

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My understaanding is that to remove all visible traces of the "amici spike" the optical tolerances of the prisms have to be exceptional. Maybe you have one that falls into that category and the others have been up to spec but no more than that ?

Edited by John
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1 minute ago, John said:

My understaanding is that to remove all visible traces of the "amici spike" the optical tolerances of the prisms have to be exceptional. Maybe you have one that falls into that category and the others have been up to spec but no more than that ?

That is often the case with many products. The actual spec which is acceptable from a manufacturing QA standpoint can be below what some might find ok. The Quark is a prime example!

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2 minutes ago, John said:

My understaanding is that to remove all visible traces of the "amici spike" the optical tolerances of the prisms have to be exceptional. Maybe you have one that falls into that category and the others have been up to spec but no more than that ?

That seems to be the currently operative suggestion, anyway...

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1 minute ago, Stu said:

That is often the case with many products. The actual spec which is acceptable from a manufacturing QA standpoint can be below what some might find ok. The Quark is a prime example!

And with a limited audience for amici prisms for astronomy - due to their inherent traits - it falls to nutters like me to find this stuff out. I accept this is so. Just got another confirmation that a perfect one will be selected for me - but will be after the Easter holiday.

So I'm kept well informed, and it will be worth the wait.

:happy11:

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i

1 hour ago, iPeace said:

And with a limited audience for amici prisms for astronomy - due to their inherent traits - it falls to nutters like me to find this stuff out. I accept this is so. Just got another confirmation that a perfect one will be selected for me - but will be after the Easter holiday.

So I'm kept well informed, and it will be worth the wait.

:happy11:

 

So does this mean the rest of us just get the satisfactory ones, and you get a hand picked perfect example?. This does seem to of opened up the flood gates here and a can of worms by Badder. I and everyone else will want a hand picked perfect example too , I suppose this means Baader going through hundreds of boxes until they find a perfect one??                                      .  

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