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#276 garret

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Posted 12 September 2018 - 12:09 PM

 

Fluorite triplets 105/1000, 135/1080 and 175/1200 - similar to Zeiss APQ - coming:

 

https://astro-theke....aktur/produkte/   (Please scroll down.)

Thanks! very useful information about glass, APO, ED, fluorite and much more if you can read German like I can (I'm from The Netherlands)

 

Gerrit van der Veen


Edited by garret, 12 September 2018 - 12:09 PM.

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#277 donadani

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Posted 12 September 2018 - 12:22 PM

Thanks! very useful information about glass, APO, ED, fluorite and much more if you can read German like I can (I'm from The Netherlands)

 

Gerrit van der Veen

Hi Gerrit,

 

did you read this too? https://astro-theke....n-apochromaten/

 

Ralf added this info just before a week or so...;)

 

cs

Chris



#278 garret

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Posted 12 September 2018 - 12:47 PM

 

Gerrit van der Veen

Hi Gerrit,

did you read this too? https://astro-theke....n-apochromaten/

Ralf added this info just before a week or so...wink.gif

Yes indeed! after reading that, all topic's and posts about  "150/ 152mm ED" are amateurish of a very low level including dealers and manufacturers  lol.gif

 

Garrett


Edited by garret, 12 September 2018 - 12:50 PM.


#279 Kent10

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Posted 12 September 2018 - 06:11 PM

Scattering on AR coatings primarily occur because of microroughness of the coating. This often follows the contours of the glass surface, i.e., the rougher the substrate, the rougher the coated surface. The coating "exaggerates" or "magnifies" the roughness of the original bare glass surface, this is why people spend so much effort trying to get the glass surface smooth prior to coating.

 

Given the same coating technology, the more coating layers there are, the more the roughness is magnified. A single-layer coating will generally be more smooth than a coating with 50 layers. So there is a design trade-off: either you add a lot of layers and increase transmission but also increase scatter, or you opt for a simpler coating structure and increase reflections but decrease scatter.

 

Or, you go for a more expensive, new coating technology that creates dense "hard" coatings of uniform thickness. Latest Pentax and other companies' expensive lens products have this on some of their surfaces. This is under the constraint that, the lens and coating has to make a profit at an end user price of a few thousand dollars in a low-volume market with potentially lots of excess inventory. Therefore the figure per lens surface cannot be more than a few hundred dollars for objectives, and a few tens dollars for eyepiece lenses.

Thanks for this information.  And that is why I have so many eyepieces.  I like them all but for different objects and they all have a different "flavor."



#280 X3782

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Posted 13 September 2018 - 05:13 AM

Yes indeed! after reading that, all topic's and posts about  "150/ 152mm ED" are amateurish of a very low level including dealers and manufacturers  lol.gif

 

Garrett

Cause if we spoke in a professional language then people get lost lol.gif

There's nothing really cutting edge here, it is about building some well-well-understood consumer optic at a reasonable price, the technology is from the 1980's, the fundamental optics design you can do yourself with a notebook computer and free software.

It is also not "premium quality" in the sense that the figure/polish per lens surface is costing a few hundred dollars max only, an hour of work is about 50-100 dollars. It's not using "the best possible materials that exist", the glass companies reserve that for more important clients/industries. It's not using the most advanced fabrication techniques that exist.

 

If you look at the equations and the data sheets and the textbooks, things are understood quantitatively, in degrees. But consumers want it broken down into marketable buzzwords that one can latch onto and understand intuitively. Then the understanding becomes black and white, and people argue in extremes, whereas reality is grey.

 

It's not about whether one explains it amateuirish or professional (that's just how good you are with marketing and setting up mystique to sell your product, and if the engineering people started doing that it's the end). It's about the consumer reading textbooks and understanding things better numerically, without the hype and the hearsay.


Edited by X3782, 13 September 2018 - 05:27 AM.


#281 daveCollins

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Posted 13 September 2018 - 11:12 AM

Warning to all:

 

I visited the site for Astro theke mention above and sent an email inquiring about their scopes.

 

I almost immediately received an extortion email threatening me with destruction and demanding a payment in Bit Coins. I was told a Trojan had been installed on my system. The email went into detail about calling the police and that sort of thing.

 

Astro Theke did not respond to my email. I would suggest staying away from the site.


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#282 donadani

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Posted 13 September 2018 - 11:43 AM

Warning to all:

 

I visited the site for Astro theke mention above and sent an email inquiring about their scopes.

 

I almost immediately received an extortion email threatening me with destruction and demanding a payment in Bit Coins. I was told a Trojan had been installed on my system. The email went into detail about calling the police and that sort of thing.

 

Astro Theke did not respond to my email. I would suggest staying away from the site.

???

 

Dave - I know Ralf Mündlein - the man behind Astro Theke personally and own two of their scopes - the third a 105 FLT is on order… I can asure you he is one of the finest astro guys and refractor nerds around! I don´t know what went wrong with your mail I have zero problems entering the site and my McAfee don´t report any threat here...

 

I have Ralfs personal mail adress too and will contact him - if you´re interested in his products I can give you the contact via PN - just let me know. 

 

cs

Chris


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#283 daveCollins

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Posted 13 September 2018 - 12:04 PM

???

 

Dave - I know Ralf Mündlein - the man behind Astro Theke personally and own two of their scopes - the third a 105 FLT is on order… I can asure you he is one of the finest astro guys and refractor nerds around! I don´t know what went wrong with your mail I have zero problems entering the site and my McAfee don´t report any threat here...

 

I have Ralfs personal mail adress too and will contact him - if you´re interested in his products I can give you the contact via PN - just let me know. 

 

cs

Chris

I was mistaken and so apologize. I received an email from the site and it was well written email which answered my questions. So issues must have had another source. Sorry for the mistake on my part.


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#284 BillP

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Posted 21 December 2018 - 04:32 PM

So I took the same diagonal, the same eyepiece, and aimed them at the same target, on the same night using my Twilight II mount.  The scatter was less in the FS-152 than the TSA -102.

 

Sounds like it should be equal since the same eyepiece in those scopes would produce the same exit pupil.  However, the magnifications are quite different with the FS152 producing 1.5x the magnification of the TSA102.  That means the halo of scatter around the star, which is in effect an extended object, will cover more area while being the same combined brightness.  So in effect appearing overall dimmer.  So even this is really an apples-oranges test given you were not working at the same magnification AND exit pupil.  Given the different magnifications your perception system will kick in as well doing its own alterations to the view given the different sizes of the scatter halo.  A better controlled test would be the TSA vs. one of the new Tak fluorite doublets of same focal ratio and aperture so you are just dealing with the double vs. triplet differences.  And additionally, exactly how much of that supposed scatter halo around the stars was from surface scatter of the glass vs water vapor or particulate scatter from the air?  I note that scatter levels around stars in a same instrument vary wildly depending on the water vapor in the atmosphere, altitude, etc.  So much of what we are "seeing" is not necessarily optical scatter from the objective at all!

 

If you want to know if fluorite has less or more surface scatter than non-fluorite then the ONLY way to determine this is with a scatterometer or other suitable instrument designed to assess surface scatter.  And further, I would want the glass tested manufactured by the same company as I am hesitant to believe that TEC, AP, and TAK are all just as adept at working with fluorite crystal.  So theory is nice for marketing blurbs to either promote their product or demote a competitors product, but in the end the skill and experience of the organization comes into play as well.  Tak of course has a significantly longer track record of working with and innovating with fluorite crystal than either TEC or AP can ever hope to muster.  Just like that ancient blurb alluding to how fluorite is fragile to temperature or water droplets. lol.gif   Never any problems in that respect from Tak, but other unskilled with fluorite manufacturers "apparently" have the problem working with fluorite.  Experience makes many theoretical issues non-issues.


Edited by BillP, 21 December 2018 - 04:49 PM.


#285 Paul G

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Posted 21 December 2018 - 07:26 PM

Sounds like it should be equal since the same eyepiece in those scopes would produce the same exit pupil.  However, the magnifications are quite different with the FS152 producing 1.5x the magnification of the TSA102.  That means the halo of scatter around the star, which is in effect an extended object, will cover more area while being the same combined brightness.  So in effect appearing overall dimmer.  So even this is really an apples-oranges test given you were not working at the same magnification AND exit pupil.  Given the different magnifications your perception system will kick in as well doing its own alterations to the view given the different sizes of the scatter halo.  A better controlled test would be the TSA vs. one of the new Tak fluorite doublets of same focal ratio and aperture so you are just dealing with the double vs. triplet differences.  And additionally, exactly how much of that supposed scatter halo around the stars was from surface scatter of the glass vs water vapor or particulate scatter from the air?  I note that scatter levels around stars in a same instrument vary wildly depending on the water vapor in the atmosphere, altitude, etc.  So much of what we are "seeing" is not necessarily optical scatter from the objective at all!

 

If you want to know if fluorite has less or more surface scatter than non-fluorite then the ONLY way to determine this is with a scatterometer or other suitable instrument designed to assess surface scatter.  And further, I would want the glass tested manufactured by the same company as I am hesitant to believe that TEC, AP, and TAK are all just as adept at working with fluorite crystal.  So theory is nice for marketing blurbs to either promote their product or demote a competitors product, but in the end the skill and experience of the organization comes into play as well.  Tak of course has a significantly longer track record of working with and innovating with fluorite crystal than either TEC or AP can ever hope to muster.  Just like that ancient blurb alluding to how fluorite is fragile to temperature or water droplets. lol.gif   Never any problems in that respect from Tak, but other unskilled with fluorite manufacturers "apparently" have the problem working with fluorite.  Experience makes many theoretical issues non-issues.

AP and TEC have rough ground, fine ground, rough polished and fine polished fluorite themselves, in house. Is Tak grinding and polishing their fluorite elements in house? I was under the impression they purchased them from Canon Optron already polished.



#286 BillP

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Posted 21 December 2018 - 07:52 PM

AP and TEC have rough ground, fine ground, rough polished and fine polished fluorite themselves, in house. Is Tak grinding and polishing their fluorite elements in house? I was under the impression they purchased them from Canon Optron already polished.

 

My understanding as well.  Meaning Canon, who apparently is subcontracted by Tak for the glass work in Taks, has way more expertise and experience.  I would imagine that the major camera makers have more experience moving glass than any telescope company...light years ahead of them.  Does not change anything.  Comparatively TEC and AP have minuscule experience with fluorite.  Tak made the wise choice and subcontracted that out to a company with vastly more experience rather than try to recreate the wheel with no hopes of ever catching up.  Canon has been using fluorite elements in their lenses since 1969!  They also currently use BR Lens technology, sub-wavelength structure coatings, miccrosphere AR coatings, regular use of aspherics, etc.  Fuji uses variable gradient glasses!  Basically camera makers are about as far ahead of telescope makers as possible relative to pushing glass.


Edited by BillP, 21 December 2018 - 08:03 PM.

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#287 junomike

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Posted 21 December 2018 - 08:04 PM

My understanding as well.  Meaning Canon, who apparently is subcontracted by Tak for the glass work in Taks, has way more expertise and experience.  I would imagine that the major camera makers have more experience moving glass than any telescope company...light years ahead of them.  Does not change anything.  Comparatively TEC and AP have minuscule experience with fluorite.  Tak made the wise choice and subcontracted that out to a company with vastly more experience rather than try to recreate the wheel with no hopes of ever catching up.  Canon has been using fluorite elements in their lenses since 1969!  They also currently use BR Lens technology, sub-wavelength structure coatings, miccrosphere AR coatings, etc.  Fuji uses variable gradient glasses.  Basically camera makers are about as far ahead of telescope makers as possible relative to pushing glass.

They (Tak) also now  have more over-head and possibly  less profit margins as they are contracting out.

Could explain the mediocre Focuser/accessories included with the high cost/Premium Tak Refractors?


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#288 marcus_z

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Posted 21 December 2018 - 08:34 PM

They (Tak) also now  have more over-head and possibly  less profit margins as they are contracting out.

Could explain the mediocre Focuser/accessories included with the high cost/Premium Tak Refractors?

I think Tak will always make cast aluminum focusers for two reasons:

1. In the history of their company they started with aluminum molding

2. In Japan people are traditional


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#289 junomike

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Posted 21 December 2018 - 08:44 PM

I think Tak will always make cast aluminum focusers for two reasons:

1. In the history of their company they started with aluminum molding

2. In Japan people are traditional

That's possible, but I still think when you pay someone else to make your lenses you have to cut costs somewhere.....(I could be wrong also).



#290 edif300

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Posted 22 December 2018 - 10:31 AM

I think Tak will always make cast aluminum focusers for two reasons:

1. In the history of their company they started with aluminum molding

2. In Japan people are traditional

 

3. There is no need for changing something working right.


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#291 marcus_z

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Posted 22 December 2018 - 10:39 AM

3. There is no need for changing something working right.

Well, with the advent of 1kg 100° eyepieces the market has changed a bit. I upgraded my Taks with Feather Touch focusers.



#292 edif300

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Posted 22 December 2018 - 10:53 AM


That's possible, but I still think when you pay someone else to make your lenses you have to cut costs somewhere.....(I could be wrong also).

 

No one is making its lenses... All them are outsourcing FPL53, 51, CaF2, FCD01....



#293 edif300

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Posted 22 December 2018 - 11:06 AM

Well, with the advent of 1kg 100° eyepieces the market has changed a bit. I upgraded my Taks with Feather Touch focusers.

Maybe 1kg has changed the world wink.gif . I am uploading more than 5kg in my Tak focusers...

 

TOA-U16m%205,5kg.jpg

 

http://www.astrosurf...m_Butterfly.jpg

 

FSQ-106EDX + KAF16803:

 

http://www.astrosurf...ED-KAF16803.jpg

 

 

And my low weight viewfinder:  bow.gif  :

 

http://www.astrosurf...eld monster.jpg


Edited by edif300, 22 December 2018 - 11:16 AM.

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#294 junomike

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Posted 22 December 2018 - 11:14 AM

 

No one is making its lenses... All them are outsourcing FPL53, 51, CaF2, FCD01....

I thought TEC, AP and the like ordered blanks and made (figured/polished) the lenses whereas Tak buys there's from Canon already finished?

Is that not the case?



#295 edif300

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Posted 22 December 2018 - 11:25 AM

I thought TEC, AP and the like ordered blanks and made (figured/polished) the lenses whereas Tak buys there's from Canon already finished?

Is that not the case?

Nor TEC nor AP are making their lenses. They are outsourcing the FPL53, CaF2, FPL51, FCD01.... They never MADE this glass. Maybe they are only polishing...

Are they even coating?


Edited by edif300, 22 December 2018 - 11:26 AM.


#296 edif300

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Posted 22 December 2018 - 11:29 AM

Making lenses is not ONLY polishing.... grin.gif



#297 junomike

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Posted 22 December 2018 - 02:20 PM

Making lenses is not ONLY polishing.... grin.gif

Ok fair enough. I was under the impression that whatever they (TEC. AP. CFF, Etc) did in-house was time consuming and thus costly as well as time = money.



#298 SandyHouTex

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Posted 23 December 2018 - 01:43 PM

Sounds like it should be equal since the same eyepiece in those scopes would produce the same exit pupil.  However, the magnifications are quite different with the FS152 producing 1.5x the magnification of the TSA102.  That means the halo of scatter around the star, which is in effect an extended object, will cover more area while being the same combined brightness.  So in effect appearing overall dimmer.  So even this is really an apples-oranges test given you were not working at the same magnification AND exit pupil.  Given the different magnifications your perception system will kick in as well doing its own alterations to the view given the different sizes of the scatter halo.  A better controlled test would be the TSA vs. one of the new Tak fluorite doublets of same focal ratio and aperture so you are just dealing with the double vs. triplet differences.  And additionally, exactly how much of that supposed scatter halo around the stars was from surface scatter of the glass vs water vapor or particulate scatter from the air?  I note that scatter levels around stars in a same instrument vary wildly depending on the water vapor in the atmosphere, altitude, etc.  So much of what we are "seeing" is not necessarily optical scatter from the objective at all!

 

If you want to know if fluorite has less or more surface scatter than non-fluorite then the ONLY way to determine this is with a scatterometer or other suitable instrument designed to assess surface scatter.  And further, I would want the glass tested manufactured by the same company as I am hesitant to believe that TEC, AP, and TAK are all just as adept at working with fluorite crystal.  So theory is nice for marketing blurbs to either promote their product or demote a competitors product, but in the end the skill and experience of the organization comes into play as well.  Tak of course has a significantly longer track record of working with and innovating with fluorite crystal than either TEC or AP can ever hope to muster.  Just like that ancient blurb alluding to how fluorite is fragile to temperature or water droplets. lol.gif   Never any problems in that respect from Tak, but other unskilled with fluorite manufacturers "apparently" have the problem working with fluorite.  Experience makes many theoretical issues non-issues.

Frankly I think your over thinking it.  Yes the magnification was different.  So what?  If I’m looking at an object that’s 2/3rds the size in my TSA versus the FS-152, and the scatter is larger than 2/3rds the size of the scatter in the FS-152, then the FS has less scatter.  I don’t need a laboratory instrument to see it.

 

People are always saying that the ZAOs are better than other Orthos from a scatter perspective, and that’s why they’re worth it.  Did THEY have to send their ZAOs and the other Orthos to a lab to figure that out?  The answer is no.

 

Isn’t it also true that in a lot of your eyepiece shoot-outs you evaluate scatter as a criteria for ranking?  Do you send your eyepieces to a lab for that?


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#299 Scott in NC

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Posted 24 December 2018 - 01:44 PM

Nor TEC nor AP are making their lenses. They are outsourcing the FPL53, CaF2, FPL51, FCD01.... They never MADE this glass. Maybe they are only polishing...

Are they even coating?

TEC and AP certainly do make lenses.  Taking a glass blank (which by itself isn't really useful for anything), then grinding, figuring, and polishing it into a lens, certainly qualifies as "making a lens."  If we can't say that those companies make lenses since they didn't make the original glass, then we might as well go to the extreme of saying that Ohara, Hoya, etc. don't make glass since they didn't produce the original raw materials (sand, etc.) from which the glass was made.  But doing so would be ridiculous.


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#300 Rich V.

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Posted 24 December 2018 - 01:56 PM

TEC and AP certainly do make lenses.  Taking a glass blank (which by itself isn't really useful for anything), then grinding, figuring, and polishing it into a lens, certainly qualifies as "making a lens."  If we can't say that those companies make lenses since they didn't make the original glass, then we might as well go to the extreme of saying that Ohara, Hoya, etc. don't make glass since they didn't produce the original raw materials (sand, etc.) from which the glass was made.  But doing so would be ridiculous.

Well said, Scott.  Reason prevails...  waytogo.gif  

 

Rich


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