57 replies to this topic

[Jeff B]

I recently took possession of a TEC 160ED, S/N 033, made in 2008.  This vintage TEC uses FPL-51 glass for the ED center element.  I don't know the mating glasses and I respect Yuri's design as proprietary so I did not and will not ask what mating glasses are involved.  The 160ED along with the 200ED (which uses an identical glass combination), were discontinued in 2010 because the reject rates for glass were too high (and no, I don't know which glass(es) was/were at issue).  There were 42 of the 160EDs produced.  The 160ED and 200ED are "scaled" to each other in design so they share some DNA other than the glass.  

 

Please be aware that this evaluation is of this particular S/N TEC 160ED.  

 

This review will be progressive, as the material develops.  I will first evaluate the physical aspects of the scope and its construction, followed by a DPAC evaluation with R,G,B LED's and maybe Y too if I'm feeling frisky.  The DPAC results will be photo-documented.  I will then evaluate the scope visually, first by itself and then, over a much longer time interval, in comparison with some other 160mm class aperture triplets frrom CFF and AP.

 

Jeff

Edited by Jeff B, 09 March 2019 - 12:22 PM.

[junomike]

 

[Tyson M]

Looking forward to it!

 

 

[zjc26138]

Can't wait to hear and see the results!

[CHASLX200]

I guess for a $8k scope used it should be a cut above in every way.

[starzonesteve]

Thanks for taking the time to undertake this in a public forum. I’m interested not only in your results but in your methodology as well. Any documentation/explanation will be appreciated.

[Jeff B]

Well, let's start off with some of the physical stuff and initial inspections.

 

First thing I did was to ditch that rotten, no good, lower than a snake's belly endcap with the standard collet.  In its place I put the endcap with a thin AP back with three locking thumb screws.  This endcap configuration has about an extra inch of back focus over the standard collet version and better grip too, both of which are very useful when it comes to bino-viewer use (more on that in a later posting). 

 

Some of the physical stuff:

 

1. Length with the new endcap and the dew shield fully retracted is 44.25".

2. Weights are as follows:

     a. Bare OTA :                                               24.5 lbs.

     b. OTA w/rings & dovetail:                           28.5 lbs.

     c. OTA as pictured ready to observe

         with rings, dovetail, finder assembly,

         diagonal and full Denk II viewer system: 34.0 lbs.

 

I was surprised at just how lite weight the assembly is.  For example in configuration c., my 140ED (with handle) is 30 lbs., my CFF F6.5 is 36 lbs., old AP 152 F9 is 34 lbs., old AP 152 F10 ATM build is 40 lbs., and former TMB/APM 152 F8 was 38 lbs.  

 

The G11 seemed quite comfortable with the OTA, which comes as no surprise as this sample of the G11 was superb with the TMB/APM 152 F8. 

 

I also found the OTA surface to have a good feel and grip to it. 

 

I did a bunch of residual back focus measurements (RBF) with several diagonals as that is important to me for bino-viewer use.  With my standard AP Maxbrite diagonal with the DPAC grating screen placed directly on the top of the diagonal (no 1.25" adapter), I measured 77mm of RBF using the shorter endcap configuration.  With my Lumicon deluxe 2" diagonal there was 83.5mm of RBF while an ancient Novak 2" diagonal from the 80's had 79.5" of RBF.  The Baader/Zeiss prism diagonal with 1.25" quick lock top measured in at 116.5mm if I pulled the diagonal out a little to reach focus while the same configured Baader BBHS silver diagonal came in at 104.5mm RBF.

 

More later.

 

Jeff

 

Edit:  Forgot to mention that whenever I get a new refractor I check the collimation of the focuser with my Glatter laser by firing it down the focuser and seeing where the exit beam lands relative to the center hole of the aperture mask I make for each scope.  To my surprise, it was off center about 3/16" or ~.2 degrees, not much but still an error.  The spot stayed put too when rotating the laser.  Backing off the FT endcap and tweaking the cap's collimation/locking screws brought the laser through the mask's center hole for the entire focuser travel.  It took me all of 5 minutes.  In fairness, this was after I had changed out the stock focuser endcap/collet for the one with the AP back but I made sure the three little collimation/locking screws on the face of the FT/AP endcap were recessed before screwing it on the focuser draw tube end.  Except for my own ATM projects, I've never had to use those screws to collimate a 3.5" FT focuser.  This was the first time the focuser collimation was off with the TEC refractors I've had (have).  To be further fair, I do not fiddle with the FT's rotation feature either, as the associated unlocking, rotation, and  locking can, by itself, introduce small amounts of error (maybe 1/16").  So I leave it alone.  Someone before me may not have.  So the error was small at ~.2 degrees and easily correctable, but I wanted to mention it for completeness.

 

After the cap tweak I checked the lens block with my cheshire eyepiece and it was great, just one round reflection dot.  

 

Jeff

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Edited by Jeff B, 10 March 2019 - 07:31 PM.

[Cosmosphil]

"First thing I did was to ditch that rotten, no good, lower than a snake's belly endcap with the standard collet.  In its place I put the endcap with a thin AP back with three locking thumb screws.  This endcap configuration has about an extra inch of back focus over the standard collet version and better grip too, both of which are very useful when it comes to bino-viewer use (more on that in a later posting)."

 

I completely agree with Jeff's decision for his set up and indeed myself purchased an AP back at time of order for the 140 which is of his vintage 2008-2009. 

I had a lengthy discussion ( as lengthy as you can get with him, maybe a minute or two) with Yuri on that subject and it was agreed that I should just order the AP back "in case".    

But, find that for standard weight eyepieces and diagonals, the "rotten" collet works fine and is beautifully machined.  As I didn't foresee and still today do not see any bino-view uses or massive 2" eyepieces I've not replaced it.   I'm sure there will be varied opinions on the collet visual back of this vintage but for me it is hardly "snake belly" level.  

[Jeff B]

"First thing I did was to ditch that rotten, no good, lower than a snake's belly endcap with the standard collet.  In its place I put the endcap with a thin AP back with three locking thumb screws.  This endcap configuration has about an extra inch of back focus over the standard collet version and better grip too, both of which are very useful when it comes to bino-viewer use (more on that in a later posting)."

 

I completely agree with Jeff's decision for his set up and indeed myself purchased an AP back at time of order for the 140 which is of his vintage 2008-2009. 

I had a lengthy discussion ( as lengthy as you can get with him, maybe a minute or two) with Yuri on that subject and it was agreed that I should just order the AP back "in case".    

But, find that for standard weight eyepieces and diagonals, the "rotten" collet works fine and is beautifully machined.  As I didn't foresee and still today do not see any bino-view uses or massive 2" eyepieces I've not replaced it.   I'm sure there will be varied opinions on the collet visual back of this vintage but for me it is hardly "snake belly" level. 

Good point. 

 

The stock collet on the new 140FL I evaluated was muuuuuch better than the older ones I have now lying around.  It had what appeared to be a different collet lining material which had much more grab to it than the older ones.  Use of bino viewers or fat but 2" eyepieces was not an issue.  They would stay put and not auto-rotate. 

 

Jeff

[Kent10]

Weren't the early collets plastic inside and then they were changed to metal.  Maybe that is the difference you are seeing, Jeff, between the older 160ED and the newer 140FL.

[vahe]

 I will then evaluate the scope visually, first by itself and then, over a much longer time interval, in comparison with some other 160mm class aperture triplets from CFF and AP.

 

 

I would be real interested in a comparison between 160ED and 160FL, both in very high power planetary performance.

.

Vahe

[DeanS]

Hi Jeff,

 

Where are you located?  I just picked up a TEC160FL this past weekend and would be interested in a comparison.  I have my TEC140ED that I will compare with it before I sell it.  Will be interesting to see if what yuri says it is true; "the main difference is in your wallet"   

 

Dean

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Edited by DeanS, 10 March 2019 - 10:22 PM.

[Jeff B]

Hi Dean and nice catch there!

 

I live about 30 miles NE of Cincinnasti. 

 

A comparison of my 160ED and your 160 FL would be fun.  I too have an exceptional 140ED, S/N 105.  It's not going anywhere.

 

Jeff

Edited by Jeff B, 10 March 2019 - 10:58 PM.

[starzonesteve]

Ummm, you guys live REALLY close to one another...

 

 

 

...

[Cosmosphil]

 I need a bib and a washcloth after these pics from Jeff & Dean........  

[DeanS]

Hi Dean and nice catch there!

 

I live about 30 miles NE of Cincinnasti. 

 

A comparison of my 160ED and your 160 FL would be fun.  I too have an exceptional 140ED, S/N 105.  It's not going anywhere.

 

Jeff

Eric has been texting me, lets wee what we can work out.  I am about 10 miles south of Lexington.

 

Dean

[Jeff B]

Dean:

 

This is sounding very doable.  We are only a couple of hours apart.  It appears Lexington dominates the north but everywhere else, especially south, seems to be very nice.

 

Eric is just a few miles away too.

 

Jeff

[rcg]

Depending on your schedules, I have a CFF165 that is supposed to arrive around the end of March/April and hopefully my mount will arrive by then. Interested in a comparison myself, I'm in Eastern Missouri about 125mi south of St. Louis. Jeff I'm Nick's friend from St. Louis.

Edited by rcg, 11 March 2019 - 06:05 PM.

[Yu Gu]

Now, this is super interesting!

I have several questions:

1. What are the visual and DPAC differences (if any at all) between 160ED and 160FL?

2. What's the impact of 25% more aperture on planet observation (resolution, low-contrast features, sensitivity to seeing, cool down time,...), 200ED vs 160ED?

3. For those people who kept both 160FL and 130GTX (and smaller travel scopes), what's the reason for using 130mm?

Clear skies!

Gu

[MooEy]

Hi Jeff,

 

Where are you located?  I just picked up a TEC160FL this past weekend and would be interested in a comparison.  I have my TEC140ED that I will compare with it before I sell it.  Will be interesting to see if what yuri says it is true; "the main difference is in your wallet"   

 

Dean

 

 

*sigh* *unzips*

[MooEy]

Now, this is super interesting!

I have several questions:

1. What are the visual and DPAC differences (if any at all) between 160ED and 160FL?

2. What's the impact of 25% more aperture on planet observation (resolution, low-contrast features, sensitivity to seeing, cool down time,...), 200ED vs 160ED?

3. For those people who kept both 160FL and 130GTX (and smaller travel scopes), what's the reason for using 130mm?

Clear skies!

Gu

Not quite the same between the 130 and the 160. You can take off the focuser from the 130 and it fits the Orion backpack nicely. The vixen sphinx breaks down to tripod and mount head and you can actually use public transport.

 

For the 160, it takes a Mach1GTO class of mount which pretty much needs a proper vehicle. The shorter ones will barely fit into a lift sideways on a trolley. The longer ones require you to carry it vertically. Fitting into a boot becomes a challenge once you go beyond that 1 meter length. 

[John Fitzgerald]

Dean,

What is the faintest magnitude you believe you have reached in your images?

[Jeff B]

Depending on your schedules, I have a CFF165 that is supposed to arrive around the end of March/April and hopefully my mount will arrive by then. Interested in a comparison myself, I'm in Eastern Missouri about 125mi south of St. Louis. Jeff I'm Nick's friend from St. Louis.

Nick has friends?  

[DeanS]

Dean,

What is the faintest magnitude you believe you have reached in your images?

Don't really have any idea, never checked.

[Jeff B]

Well, I cheated the new scope curse and had a night of exceptional seeing and transparency so I took the 160ED out for a spin in my side yard.  The initial goal was to evaluate several bino-viewer/diagonal combinations for focus with the 160ED but went way beyond that as the seeing was at times just excellent, sub arc at times.  

 

The only bino-friendly combinations were the Baader/Zeiss T2 diagonal and the Baader Mark V and Zeiss viewer I got from Denis Levatic with 30mm prisms.  These combinations are suitable only for very low to moderate powers as chromatic effects of the stacked prisms started to intrude at ~100x.   But the low power views of the moon were spectacular with my 30 & 35 mm Ultimas and, especially,my pair of Denk 32mm Plossls (I continue to be impressed with these eyepieces). 

 

All other viewer/diagonal combinations required use of the Denk OCS/power switch system (I have an adapter to allow the Zeiss viewer to be mated with the Denk power switch).  

 

This scope has excellent, sharp optics.  The moon had that etched quality to it that I have come to associate with truly high quality optics.  I ran the thing up to ~ 240X on the Moon and it was sharp like you read about with no visible color error along with a rather neutral color tone.  

 

I did star testing on Rigel, Betelgeuse, Castor, Pollux, and Sirius.  I did not use a green filter and all testing used the Denk II viewer with either a single select OCS/sweeper combination giving about 1.5X or the Denk II with an OCS/power switch giving ~1.4X/2.0X/2.8X.  I actually selected these combinations in DPAC as they and the Zeiss viewer similarly configured, seemed to correct the subtle undercorrection I saw in green light. 

 

The star testing was just excellent, especially really close to focus where the diffraction rings just fell uniformly down into and climbed out of focus showing a very tight airy disk with one faint, uniform ring.  I could see no spherical effects other than the chromatic effects visible in the intra and extra focal images.  There was no astigmatism or coma that I could see even up to over 300X.  The tested stars showed their distinctive natural colors at focus.  Only at very high power (north of 250X) could I start to catch out a bit of stray blue with a little bit of a subtle yellow tint to the stellar cores.  There was very little "junk" and scatter around the stars at high power focus, which demonstrated the excellent seeing and cleanliness of the optical train.  Even Sirius was "clean", very steady, very bright, very blue/white and ...

 

And I wasn't even really looking for it...

 

The Pup. 

 

I just happened to notice it at about 180X and it was steady sometimes for a good 30 seconds or so.  I turn off the drive and let the two drift across the field to make sure I was not picking up some form of stray light.  Yup, the Pup ran with its master.  A very pleasant unexpected surprise.    

 

Time to finish up my DPAC work and post it.

 

Jeff

Edited by Jeff B, 12 March 2019 - 08:14 AM.