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Are Unitron objectives lenses bad?

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#101 CHASLX200

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Posted 28 April 2021 - 05:47 AM

I would be livid if I plopped down $50,000 for a 6 inch Unitron and the lens really sucked.

That is why you test first if paying that much.  I would hate to see what shipping a 800lb 6" would cost.


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#102 LukaszLu

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Posted 28 April 2021 - 08:01 AM

does anyone know what the "Passed Japanese Optical Institute" Means?  Like what kind of test was done?  What was the Japanese Optical Institute?

We would have to start with the question of whether "JTII (Japan Telescopes Inspection Institute)" really existed at all, or was it just a marketing product, such as "institutes" established only to display their stamp on toothpaste and washing powder commercials? Was it a government initiative aimed at supporting Japanese exports, or was it an idea of ​​producers to improve their competitive position? Or maybe it was the initiative of someone who decided that he would make money from optics manufacturers by selling them such certificates and stickers, as is the case with various "eco" certificates, "customer laurels" etc ...?

 

Why on the Internet you can not find any traces of this "institute" or information about it? This question bothers me, if only because I have the Kenko telescope, with optics having such manufacturing defects that it should not have passed any test - and yet the telescope is proudly decorated with the "Passed JTII" sticker ...



#103 DAVIDG

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Posted 28 April 2021 - 08:13 AM

I would be livid if I plopped down $50,000 for a 6 inch Unitron and the lens really sucked.

 Things similar to this happen all the time even today. The forums  on this site are full of messages were someone has bought an expensive scope and the image quality is not what they expect. Then the suggestions start that it is collimation, it is seeing, the scope hasn't cooled enough, you need a better eyepiece, you need a better diagonal etc  but rarely does anyone say test your optics. Just do a simple star test. Amateur believe the hype that they are getting amazingly perfect optics all the time and that can't be the problem as to why the image is no good. It has to be something else since the ad say I'm getting "Optics that are laser tested   that can show 1/50 wave errors  and that are guaranteed to perform to theoretical limits and made by ultra skilled craftsman"  The fact that when people start testing optics and these bad ones show up, that should tell you that they were not  testing their optics or their standard were very loose. 

   The biggest example was the Hubble. They tried a number of things  to clear up the fuzzy image until it final sunk in that the optics were figured wrong. All they had to do is take an image of star that was defocused the same amount on each side of focus and they would have seen the difference and know what the problem was. 

   The telescope industry for many years as operated under " Your satisfaction is guaranteed"  not that the optics will meet a certain  wave rating. So if your happy with the image great, if not we'll give you another scope or your money back. If they only get a small percentage of returns that doesn't affect their profits they will continue to make that level of product.

 

                 -Dave


Edited by DAVIDG, 28 April 2021 - 12:36 PM.

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#104 clamchip

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Posted 28 April 2021 - 09:15 AM

Here's info on JTII:

1961 http://home.europa.c...cope/61jtii.jpg

 

1966 http://home.europa.c...cope/66jtii.jpg

 

1973 http://home.europa.c...cope/73jtii.jpg

 

Robert


Edited by clamchip, 28 April 2021 - 09:19 AM.


#105 starman876

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Posted 28 April 2021 - 10:41 AM

so they tested each telescope?I find that hard to believe.  I am sure this was some percentage of each lot that was tested.


Edited by starman876, 28 April 2021 - 10:55 AM.


#106 photiost

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Posted 28 April 2021 - 10:46 AM

I suspect then every so often some lemons did get a clean pass  ... 



#107 starman876

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Posted 28 April 2021 - 10:55 AM

I suspect then every so often some lemons did get a clean pass  ... 

looks like an advertising gimmick to me.



#108 Terra Nova

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Posted 28 April 2021 - 11:08 AM

I suspect then every so often some lemons did get a clean pass  ... 

https://youtu.be/MLhYghzNfII


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#109 SteveGR

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Posted 28 April 2021 - 11:25 AM

Never had a TV scope.  If they are as good as a Tak then i would love them.

They are good, not sure if they are quite Tak good... but they are also different beasts, they are faster Petzval designs (at least the ones I have seen).  the Genesis(es)? I have looked through were nice.

 

To the original question of the thread, for the Unitrons I have looked through, my socks always remained on, not even any serious pressure to try to knock them off. A couple I would call good, and one I would call atrocious.  They sometimes are better to look at then look through. smile.gif


Edited by SteveGR, 28 April 2021 - 11:25 AM.

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#110 DAVIDG

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Posted 28 April 2021 - 11:56 AM

looks like an advertising gimmick to me.

 Maybe but a certain percentage were checked and like I said the ones I have tested have tested well.  When it comes to Unitrons especially the 4" models  and ones  with larger apertures I don't believe they could have sold more then 100 or so per year. So it 's not like they were making thousands per year and  a  couple of bad ones slipped by. Each one of those lens should have been  checked. It would take no more then 15 minutes to test them.  They could have simply used an artificial star  to examine the images on both side of focus and in focus and that would have easily shown if there was an issue.  If you have the skill to make a lens you have the skill to test it correctly as well. Those skills go hand in hand or your  not making a lens your making a polished piece of glass.  You don't need a $50,000 Zygo Interferometer.  A ball bearing placed a mile away and a glint of sunlight off it makes a pretty  good artificial star  that will show you the lemons. 

 

               - Dave 


Edited by DAVIDG, 28 April 2021 - 03:30 PM.

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#111 starman876

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Posted 28 April 2021 - 12:14 PM

 Maybe but a certain percentage were checked and like I said the ones I have tested have tested well.  When it comes to Unitrons especially the 4" models  and ones  with larger apertures I don't believe they could have sold more then 100 or so per year. So it 's not like they were making thousands per year and  a  couple of bad ones slipped by. Each one of those lens should have been  checked. It would take no more then 15 minutes to test them.  They could have simply used an artificial star  to examine the images on both side of focus and in focus and that would have easily shown if there was an issue.  If you have the skill to make a lens you have the skill to test it correctly as well. Those skills go hand in hand or not making a lens your making a polished piece of glass.  You don't need a $50,000 Zygo Interferometer.  A ball bearing placed a mile away and a glint of sunlight off it makes a pretty  good artificial star  that will show you the lemons. 

 

               - Dave 

Unitron did not have a test bench.  I doubt they checked the lens on an artificial star.  All they checked for was the Newton rings.   Maybe they depended on information from Japan on the quality of the lenses.


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#112 clamchip

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Posted 28 April 2021 - 01:03 PM

The JTII inspections were done by a Japanese government authorized institute.

 

Robert


Edited by clamchip, 28 April 2021 - 01:06 PM.


#113 Kasmos

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Posted 28 April 2021 - 02:07 PM

It could probably use some more tweaking but my circa '57 Unitron 114 was at first a bit of a disappointment.

It's been improved but in side by side testing it was still out performed by the Celestron/Vixen C60, and the '58 Bushnell Sky Chief. 

V-vs-U.jpg

B-vs-U.jpg

That said, if you didn't have something for comparison, you'd likely be happy with it's performance.


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#114 CHASLX200

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Posted 28 April 2021 - 06:09 PM

 Things similar to this happen all the time even today. The forums  on this site are full of messages were someone has bought an expensive scope and the image quality is not what they expect. Then the suggestions start that it is collimation, it is seeing, the scope hasn't cooled enough, you need a better eyepiece, you need a better diagonal etc  but rarely does anyone say test your optics. Just do a simple star test. Amateur believe the hype that they are getting amazingly perfect optics all the time and that can't be the problem as to why the image is no good. It has to be something else since the ad say I'm getting "Optics that are laser tested   that can show 1/50 wave errors  and that are guaranteed to perform to theoretical limits and made by ultra skilled craftsman"  The fact that when people start testing optics and these bad ones show up, that should tell you that they were not  testing their optics or their standard were very loose. 

   The biggest example was the Hubble. They tried a number of things  to clear up the fuzzy image until it final sunk in that the optics were figured wrong. All they had to do is take an image of star that was defocused the same amount on each side of focus and they would have seen the difference and know what the problem was. 

   The telescope industry for many years as operated under " Your satisfaction is guaranteed"  not that the optics will meet a certain  wave rating. So if your happy with the image great, if not we'll give you another scope or your money back. If they only get a small percentage of returns that doesn't affect their profits they will continue to make that level of product.

 

                 -Dave

I guess Celestron and Meade got away with 1000's of not greats scopes over the years.  And for sure the D8 SCT.



#115 SandyHouTex

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Posted 28 April 2021 - 06:36 PM

es Unitron did not have a test bench.  I doubt they checked the lens on an artificial star.  All they checked for was the Newton rings.   Maybe they depended on information from Japan on the quality of the lenses.

What kind of a test just uses the”Newton rings”?

 

And I have to say that I am utterly flabbergasted that Unitron did not test their optics.  That being said, why in the world are they considered “collectable”?
 

Maybe I should start investing in the old Coulter dobs.  Sounds like a similar proposition.

 

Good gravy!


Edited by SandyHouTex, 28 April 2021 - 06:42 PM.


#116 SandyHouTex

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Posted 28 April 2021 - 06:37 PM

I guess Celestron and Meade got away with 1000's of not greats scopes over the years.  And for sure the D8 SCT.

Except that Celestron and probably Meade had actual test facilities.



#117 starman876

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Posted 28 April 2021 - 07:19 PM

Except that Celestron and probably Meade had actual test facilities.

now that is a good point.  Why would a company with test facilities produce bad scopes.  Maybe Tim can chime in here.  He worked at Meade.



#118 DAVIDG

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Posted 29 April 2021 - 09:31 AM

now that is a good point.  Why would a company with test facilities produce bad scopes.  Maybe Tim can chime in here.  He worked at Meade.

 That is easy, PROFIT.  Time is money so if the consumer accepts the quality you produce that is all you need.  Meade and Celestron could have a $50,000 Zygo interferometer and test every set of optics but the release spec could be 1/2 wave or better. So if 99.9% test out at 1/2 wave  then ship it.. It meets spec.  If  an acceptable amount of returns happen that don't cut into profit then why change ?  If you determine that your process is robust enough that the optics you make are mostly in spec then you can relax your testing frequency and again let the customer provide the feed back if the your produce is good enough. That was Meade business model and model for many business.

    It also depends on what test you are  doing and how well the person doing the test is trained. From Gil's article about the testing at Criterion on the Dynamax series, they used a laser at the focus  of 8" Newtonian to produce an artificial star. That can be a very informative test when done correctly. The problem is that the technician doing the testing was examining the in focus image of the artificial star. That gives limited information on the quality of the optics. It tells you if the optics are collimated and if the their is astigmatism. It tells you nothing of the amount amount of spherical aberration or roughness of the optics. The really information comes when you compare the defocused images of the star on each side of focus. Now it easy to tell how good the scope is corrected  but Criterion was not  using that test. So their test method meet their spec so ship it  and we all know what that led too ! 

     The truth keeps coming out when amateur start testing their optics and see what they really have.  So when it comes to Unitron lenses it sounds like they  accepted the quality of the optics provided to them with no verification and amateurs assumed they were getting quality optics. 

 

                - Dave 


Edited by DAVIDG, 29 April 2021 - 01:03 PM.

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#119 bremms

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Posted 29 April 2021 - 12:10 PM

Funny I saw this thread. I was playing around in my telescope junk room and wanted to look at a couple lenses with DPAC.  3.25" F15 Jaegers was superb. Straight nice lines 80mm Towa.. well not bad but not good. Vixen 80mm F11 from a first scope 80.. Looked as good as the Jaegers, but I knew that one had a good lens.

So I have two Unitron 60mm F15 lenses one from the probably mid sixties and one from the early 70's( chipped.)

The one from the 60's is good but not great.

The one from the 70's is not very good.

The 4" Unitron I looked through every now and then as a teen I was never impressed with always had a soft focus and my  RV6 was better. Wonderful mechanics on the 4" Uni but MEH optics.

A friend had a 3" that was super sharp. Airy disc was perfect on doubles in that one.


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#120 SandyHouTex

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Posted 29 April 2021 - 04:51 PM

I guess I can cross “get a Unitron” off my bucket list.



#121 MtnGoat

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Posted 29 April 2021 - 05:32 PM

Since there's some drift approved by the OP...anyone know what this label tells me about the date of what I think is an early 140? 

label.jpeg

 

alt-az head

mount head s.jpg


Edited by MtnGoat, 29 April 2021 - 05:32 PM.

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#122 starman876

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Posted 29 April 2021 - 05:37 PM

Go to the Company Seven web site or check the Unitron History website.


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#123 starman876

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Posted 29 April 2021 - 05:41 PM

I guess I can cross “get a Unitron” off my bucket list.

Not all lenses were bad.   The majority of the lenses I have tested were excellent.  There were a few that were not the best I have seen.    I sense it is like any other scope.  The good ones people hang onto.  The bad ones get passed around on a regular basis.  People buy them realize the lens is not that great and quickly sell it.  I bet that happens with a lot of scopes.  If the same bad scope gets into enough hands then slowly that brand or model will get a bad name.  I have had dozens and dozens of Unitrons and I have only found a handful so far with bad lenses.  The bad lenses stay with me.  I do not pass them on.  


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#124 CHASLX200

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Posted 29 April 2021 - 06:07 PM

My 1960 4" M-152 could do 400x fine.  It was a very good lens when i got it in 1986. I had to send it to Unitron as it sat in the boxes for about 25 years and the lens was fogged up.  They got most of it.


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#125 Terra Nova

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Posted 29 April 2021 - 07:56 PM

Since there's some drift approved by the OP...anyone know what this label tells me about the date of what I think is an early 140? 

attachicon.giflabel.jpeg

 

alt-az head

attachicon.gifmount head s.jpg

Judging from your mount and the way it’s bolted to your tube, I would place it around 1954 to 1955. The red label and Milk Street address is consistent with that date.


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