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TEC-itis!

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#351 peleuba

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Posted 01 May 2020 - 08:47 AM

This was posted today in Yuri's fb group.

 

I thought I would share this here as well, to all those afflicted or think they will become afflicted...

 

attachicon.gifFB_IMG_1588262279271.jpg

 

 

Tyson - thanks for posting... I saw this a few days back when Yuri was discussing it and I was a little suprised to see it.  I have owned three TEC OTA's purchased from Yuri and was fortunate enough to tour the TEC "factory" in Golden, CO some years back.  From the slightly less then ½ day I spent at TEC I came away knowing that TEC is the "real-deal" when it comes to making telescopes.  They control almost every single part of the process from optical manufacturing to OTA fabrication.  At one point, TEC was even producing focusers for their OTA's but have switched back to the FT3545.  So, it may be better to outsource some of the production to SME (subject matter expert) type of companies on expensive, hard to produce parts. 

 

When the conversation with Yuri, Alex and Eduard got around to optical fabrication Yuri told me that they do not use interferomtery on every serialized lens.  They did use test plates and double pass auto collimation among some other methods.  

 

In any event, seeing Yuri's post surprised me (in a good way) that interferometry has become part of the standard production process.  As good as the star test, double pass, foucault etc. is - these tests are qualitative.  Sure, they can help discern a great optic from an average optic from a poor optic; but, only an interferometer is able to assign wavefront ratings and truly measure the lens or mirror under test.  When an interferometer is used in a production environment two things happen:  (1) It tells the optician when the lens meets the minimum spec and is, therefore, finished;  (2) It certifies the lens.

 

In the TEC io.group Yuri mentioned that he can test up to a 100 lenses per day.  And, while I am not privy to the TEC testing process, interferomtery is very sensitive to temperature deltas in the glass.  Meaning that after you touch a lens to move it onto the test stand, the interferometer will give wildly inaccurate readings because the surface of the glass changed shape from the heat of your hands touching it while moving it into place on the stand.  Sometimes you need to wait 15 minutes or more depending upon the size of the lens under test.

 

It would be very good to know what wavelength (color) Yuri is testing at.  The most common is red (635nm) but most refractive optics are nulled in green.  If testing in red, the results when testing in green will be worse.  There is no reliable way in which you can use simple math to convert the PtV/RMS/Strehl in red to what the equivalent would be in green because of the effects of spherochromatism.  


Edited by peleuba, 01 May 2020 - 09:47 AM.

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#352 Heywood

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Posted 01 May 2020 - 11:28 AM

Tyson - thanks for posting... I saw this a few days back when Yuri was discussing it and I was a little suprised to see it.  I have owned three TEC OTA's purchased from Yuri and was fortunate enough to tour the TEC "factory" in Golden, CO some years back.  From the slightly less then ½ day I spent at TEC I came away knowing that TEC is the "real-deal" when it comes to making telescopes.  They control almost every single part of the process from optical manufacturing to OTA fabrication.  At one point, TEC was even producing focusers for their OTA's but have switched back to the FT3545.  So, it may be better to outsource some of the production to SME (subject matter expert) type of companies on expensive, hard to produce parts. 

 

When the conversation with Yuri, Alex and Eduard got around to optical fabrication Yuri told me that they do not use interferomtery on every serialized lens.  They did use test plates and double pass auto collimation among some other methods.  

 

In any event, seeing Yuri's post surprised me (in a good way) that interferometry has become part of the standard production process.  As good as the star test, double pass, foucault etc. is - these tests are qualitative.  Sure, they can help discern a great optic from an average optic from a poor optic; but, only an interferometer is able to assign wavefront ratings and truly measure the lens or mirror under test.  When an interferometer is used in a production environment two things happen:  (1) It tells the optician when the lens meets the minimum spec and is, therefore, finished;  (2) It certifies the lens.

 

In the TEC io.group Yuri mentioned that he can test up to a 100 lenses per day.  And, while I am not privy to the TEC testing process, interferomtery is very sensitive to temperature deltas in the glass.  Meaning that after you touch a lens to move it onto the test stand, the interferometer will give wildly inaccurate readings because the surface of the glass changed shape from the heat of your hands touching it while moving it into place on the stand.  Sometimes you need to wait 15 minutes or more depending upon the size of the lens under test.

 

It would be very good to know what wavelength (color) Yuri is testing at.  The most common is red (635nm) but most refractive optics are nulled in green.  If testing in red, the results when testing in green will be worse.  There is no reliable way in which you can use simple math to convert the PtV/RMS/Strehl in red to what the equivalent would be in green because of the effects of spherochromatism.  

The pictured chart states that the test wavelength is 543 nm, i.e., green.


Edited by Heywood, 01 May 2020 - 11:31 AM.


#353 peleuba

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Posted 01 May 2020 - 11:53 AM

The pictured chart states that the test wavelength is 543 nm, i.e., green.

 

It does indeed.  I missed that.  Thank you.



#354 jrbarnett

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Posted 01 May 2020 - 03:15 PM

TEC's suck.

 

I mean how foolish to eliminate light scattering, polish-dependent surfaces in the optical train.  Much better to add big hard to thermally equalize air gaps and additional dependencies of precise polishing and perfect coating selection and application on additional surfaces.

 

I mean just LOOK at that beautiful objective - nice obvious GREEN coatings (green's good, right?  the color of money), and it has gen-uine fluorite!

 

Compare it to my TEC.  What a piece of junk!  As you can plainly see, they didn't even include an objective!  No glass!  You can see the aluminum rear cap plainly, no glass, no coatings.  Bah!  That danged Yuri "Vic's your Daddy" Petrunin.  A real piece of work.

 

whistling.gif

 

- Jim

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Edited by jrbarnett, 01 May 2020 - 03:16 PM.

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#355 Jsquared

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Posted 02 June 2020 - 11:31 AM

Does anyone know if the recent tec 140 increase price applies to those who’ve paid deposit with invoice and are waiting for scope delivery or just new orders ?

#356 Thom

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Posted 02 June 2020 - 11:45 AM

Does anyone know if the recent tec 140 increase price applies to those who’ve paid deposit with invoice and are waiting for scope delivery or just new orders ?

It applies to people who have already paid deposit with invoice and are or were awaiting shipment. I was notified last week.
 


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#357 Heywood

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Posted 02 June 2020 - 02:51 PM

It applies to people who have already paid deposit with invoice and are or were awaiting shipment. I was notified last week.


Ha! I knew it! The last price increase worked in the same way!

#358 ryderc1

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Posted 02 June 2020 - 03:17 PM

Ha! I knew it! The last price increase worked in the same way!

I believe those who already had placed an order were offered a free pair of TEC rings ($330 new) for the scope if they maintain their orders or a waiver of the normal cancellation fee if they cancel their order within a reasonable amount  of time. Seems like a very fair approach to me.



#359 Heywood

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Posted 02 June 2020 - 05:42 PM

I believe those who already had placed an order were offered a free pair of TEC rings ($330 new) for the scope if they maintain their orders or a waiver of the normal cancellation fee if they cancel their order within a reasonable amount  of time. Seems like a very fair approach to me.

 

Oh, I agree.  Very fair.  Actually, more than fair!

 

Heywood



#360 Jsquared

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Posted 02 June 2020 - 11:18 PM

I believe those who already had placed an order were offered a free pair of TEC rings ($330 new) for the scope if they maintain their orders or a waiver of the normal cancellation fee if they cancel their order within a reasonable amount of time. Seems like a very fair approach to me.


I looked through my email and found my notification. Since rings were part of my order the blow was softened to a total increase of “only” 470$. Attached was an amended invoice. Sigh

Repeat after me “it will be worth it”

#361 ares53405

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Posted 03 June 2020 - 12:51 PM

I looked through my email and found my notification. Since rings were part of my order the blow was softened to a total increase of “only” 470$. Attached was an amended invoice. Sigh

Repeat after me “it will be worth it”

“It will be worth it”, “It will be worth it”, “It will be worth it”.  I own a TEC 140ED and can officially say, “It will be worth it”!  waytogo.gif

You're going to have a lot of fun with that scope!  Wishing you clear and steady skies.  Mark


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#362 Joel-1793

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Posted 03 June 2020 - 01:21 PM

TEC 200FL f/8 on AP1200 mount, SN #001 from 2005 in Arizona!

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#363 Jeronimo Cruz

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Posted 03 June 2020 - 01:44 PM

WOW!!!

 

PM sent Joel.



#364 Noltimier

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Posted 06 June 2020 - 04:15 PM

Hello everyone.

 

I put in my order for a TEC 140FL last August through Anacortes Telescope. 

Happy to say it finally arrived yesterday...All I can say right now is this piece of equipment is a work of art!

Even more unbelievable is that tonight through Monday we are supposed to have clear skies.

 

TEC 140 FL WITH CASE.jpg

 

I'll post an image of the objective next.

 

Mark

 


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#365 Noltimier

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Posted 06 June 2020 - 04:19 PM

Here is the objective.

TEC 140 FL OBJECTIVE.jpg

 

I hold all of you responsible for taking me down this pathsmile.gif

Thanks!

 

Mark

 


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#366 Scott in NC

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Posted 06 June 2020 - 05:29 PM

Nice, Mark! :waytogo:



#367 Heywood

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Posted 06 June 2020 - 07:20 PM

Hello everyone.

 

I put in my order for a TEC 140FL last August through Anacortes Telescope. 

Happy to say it finally arrived yesterday...All I can say right now is this piece of equipment is a work of art!

Even more unbelievable is that tonight through Monday we are supposed to have clear skies.

 

attachicon.gifTEC 140 FL WITH CASE.jpg

 

I'll post an image of the objective next.

 

Mark

 

Did you buy that case from TEC?

 

Thank you!

 

Heywood



#368 Noltimier

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Posted 07 June 2020 - 10:07 AM

Hi Heywood.

 

The case was ordered from TEC via Anacortes at the same time as the telescope, rings and carrying handle.

 

Mark



#369 Haydon

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Posted 07 June 2020 - 10:22 AM

They are excellent cases- lighter weight than Scopeguard style cases and yet very well built and robust.  They have great storage too.



#370 WE349A

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Posted 14 July 2020 - 01:22 PM

Just chiming in to say that after 18 months or so of ownership, I still love my 140FL. Perfect size, amazing quality.
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#371 Scott in NC

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Posted 05 September 2020 - 09:50 PM

TEC 140 set up for observing tonight!  If you look closely you can see Jupiter and Saturn in the background (upper right of the image).

 

9DCD6E03-B674-45D6-8349-06EAD0366891.jpeg

 

 


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#372 jena100

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Posted 06 September 2020 - 01:21 PM

I bought a TEC140ED back in 2014.  Naturally, I looked through old internet posts for encouragement that I'd get my scope quickly.  I think I found a couple of posts where people said they got their scopes in two months.  I even had a chance to talk to Yuri about it at an astronomy show.  My scope took over 11 months.  I was dismayed that it took so long, but I was not surprised.  Going back to the days when I bought a Cave 8-inch reflector in 1973, I've found that it's reasonable to double any verbal or printed time estimate for a custom-made piece of astro hardware.  If it arrives sooner, then count yourself lucky.

Tom Cave was a friend of mine going back to 1946. He started Cave Optical in 1953 if I remember correctly. You are right about time quotes from any custom telescope maker. They mean well with the quotes, but just let them work and enjoy the results when you get it. Tom made a pier mounted 8" f-7 for me in 1963. I sold it in 2006 while waiting for my TEC 140. Dumb me. I wish I had that Cave. I do have the 140 S/N 84. I will not be dumb again. I think I will have it placed in my casket.


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#373 Alan S

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Posted 08 September 2020 - 04:33 PM

Took the 140 with me for some fun after work yesterday...pushed the color a bit for this blue hour shot - because...why not!?!  I always tell my colleagues that the best scope at the observatory is the one in the foreground lol.gif

 

MLSC_TEC.jpg


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#374 Jsquared

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Posted 09 September 2020 - 10:06 PM

Anyone know the light range of TEC lens coatings ? Does it pass infrared ?

#375 alan.dang

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Posted 11 September 2020 - 01:30 AM

Anyone know the light range of TEC lens coatings ? Does it pass infrared ?


It should. When you look at Baader, they quote the focus shift to 1000nm.
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