TEC160ED for sale on Astromart

[gregbradley]

This would be an awesome scope. You can't buy an AP160 but you can buy a relatively similar TEC160ED.

http://www.astromart.com/classifieds/details.asp?classified_id=726577

With the Aussie dollar at alltime highs this must be an awesome opportunity for someone. I haven't seen one of these for sale before.

Yuri makes a flattener as well.

Greg.

[telemarker]

It didn't last long.

[gregbradley]

No it didn't last long at all. I wouldn't've been the only to see that as a desirable scope.

Look at the alternatives to a TEC160ED:

TOA150 which is 10mm less aperture and more expensive by about $3000 after accessories (TEC scopes come with rings).

AP160 - almost impossible to buy.

AP155 - one for sale for US$9750 - a lot more expensive, 5mm less aperture, similar type of lens setup, not a feathertouch focuser although AP focusers are very very good but the one on AMart is the greased one not the later greaseless. Flattener is about US$2000 whereas TEC one is US$750.

TMB152 - these get a good review but depends on what type of focuser/tube as there have been many varieties. The earlier heavy model has a focuser like a tank and the later ones have a nice feathertouch.
Also more expensive, 8mm less aperture, not a feathertouch usually and lower strehl usually than AP or TEC which run at .99 strehl which puts them at the absolute high end with AP having the edge over TEC for other fineries in the scope.

The only "worry" about the TEC160ED is the main lens is FPL 51 rather than FPL53. Not sure why, perhaps availability of glass or cheaper for much the same performance. I don't think there is much difference between the 2 glasses.

Greg.

[rally]

Greg,

My comments are more specifically AP rather than visual.

I think you should be comparing the TEC160FL with a TOA150 not the TEC160ED in terms of colour correction.

The FL is/was more expensive than the ED too !

Where are the strehl ratio specs and the longitudinal chromatic aberration charts for the TEC to support this.

The aperture increase is 14% more light - sure its worth something (more for visual than AP) but not if the colour correction and strehl are not in the same league.

The TOA150 is near perfectly corrected from IR to UV and a strehl ratio of 99.2% (theoretical perfect is 100%) making it a perfect maging scope.

But I am sure its a nice scope

Cheers

Rally

PS When does it arrive !!!

[Zaps]

Even Roland Christen has admitted that for astrophotography at least the TOA are the best color-corrected instruments available, better even than his own.

[Waxing_Gibbous]

I think you'll you'll find that the 160 ED is made with FPL53.
The 160 FL is made with Calcium Fluorite as the colour correcting element.
Its more expensive as it is more expensive to produce. The regulations governing its manufacture are quite strict (principally with regard to disposal of the toxic by-products).

As a BTW: Contrary to general belief CaFl2, which is a crystal, is much easier to figure than ED glass and can be produced in batches with very little variation from 'perfect'.

[rmcconachy]

The TEC f/7 140ED uses FPL-53 but the f/8 160ED uses FPL-51. Yuri has suggested that he might one day make a version of the 160ED with a focal ratio between f/7 and f/8 using FPL-53. This information is sourced from posts Yuri has made to the TEC Yahoo group.

[Kal]

Some useful information there.

I went to the TEC yahoo group to look up some more information and found this post by Yuri (http://tech.groups.yahoo.com/group/tec-scopes/message/10757) to be enlightening with regards to the larger FPL-51 TEC scopes:

Hi Jack,
I did not know that optical glasses could be classified by fragility
or classes from lowest to highest. As far as I know, the glasses are
usually different by optical properties, homogeneity, stress
birefringence, striae and bubble contents.
We are working with FPL51, FPL53, CaF2. The difference between last
two were discussed in post #9803 and earlier. Price wise - no much
different between FPL51 and FPL53, for example, cut blank of FPL51 for
APO160ED costs 3.8 times more than molded blank of FPL53 for APO140.
As it was said here the color correction of triplet depend not only on
the middle lens, but two other matting glasses. FPL53 and Fluorite let
us have faster optics. Optics in APO160ED and APO200ED are a bit
slower and color correction is optimized for visual observation.
Roland's APO160 F7.5 was designed for CCD imaging in first hand, where
the high color correction in wider spectral range is required, and
requested using air-spaced design and FPL53 glass...
So, your attemp to distinguish FPL51 as lowest class glass I would
call as incorrect.
regards, Yuri

So Yuri infact confirms that the 160ED and 200ED are optimised towards visual observation.

[Waxing_Gibbous]

I stand corrected. I got my info from some guy in a bar. :)

[gregbradley]

I think it is hard to compare the highend APOs for astrophotography.

Certainly there is a point where the difference is so hard to notice you would be better off with a larger aperture compound scope. Most astrographs are compound scopes.

APO imaging though has a wonderful appeal.

For sure the TOA 150 is right up there with the best. I find 99.2% strehl hard to believe especially when Tak do not make their own lenses. Also if you live in an area with rapidly falling temperatures the TOA150 may not be the best scope there as I wonder what the cooldown time is and whether the lens keeps up with rapidly falling temps with such a large air gap. Obviously in Sydney it works fine but then Sydney does not have rapid drops in temp really.

Marcus's images consistently show that bit extra resolution that you would not expect from 150mm aperture. Mike's AP152 consistently surprises with its resolution.

I myself tested my TEC180FL and AP140 on the same object with the same camera and the same location and there really wasn't anything in it except image scale and more detail as expected from the larger aperture.

Yuri has just posted he no longer makes the APO160ED as he can no longer get the glasses.

This has been a trend for AstroPhysics and TEC. AP no longer really makes anything besides 130's and Honders Riccardi and hopefully soon the Mak Cass. Roland can make 140s and 160s. Not sure what his plans are there but I don't think there have been anymore 160s made since 2005. I bet supply of the glass and its cost is the main bugbear plus the extra work of making an air spaced triplet versus an oilded triplet.

I think you would be looking a long time to get a scope better than the TEC160ED which is no longer made. Sure the 160fl would be better but would it even be noticeable? Maybe - hardly though.

Moot point now as it is no longer made. How long before TEC160 and 180 are no longer made. So its been 200Fl, 200ED and now 160ED no longer made due to inability to get the glass.

At this rate it could end up that TMB make the only large scopes from Russian glass.

I predicted this trend and was one reason why I stretched myself to get the TEC180 whilst they were still being made.

I bet a bunch of guys who've been around a long time kick themselves for not getting an AP155 or AP160 or AP180 when they were being made.

Greg.