[SOLD] Expressions of Interest TEC180 Fluorite

[gregbradley]

Unfortunately due to family reasons I am forced to sell my beloved TEC180 fluorite oil spaced triplet. Otherwise I would never consider it.

This is an exotic scope and one of only one or 2 others in Australia. At one stage (for a few years) Yuri no longer made more of these as he could not get the exotic fluorite glasses needed. New price is US$19,000 + shipping, +GST and a 1 year wait (or longer). There is no guarantee he will continue to make these in the future as the trend for APO makers is to make these type of exotic instruments and then stop and settle on smaller apertures like 140mm or smaller.

This one is a proven performer and a stunning instrument. Its the largest APO refractor that can be handled by one person and still portable. I use it on a PMX mount which handles it well. It also gives spectacular visual views if someone wanted to use it for visual work.

I also have custom rings (German) as well as the standard TEC ones and a field flattener which can be added to the sale. It comes with the better Feathertouch F3545 focuser with the microfocuser knob and rotating focus unit with zero flex. The focuser is a delight to use. It also fits a Robofocus unit easily.

It has a custom end cap and a eyepiece holder with a brass compression ring.

Imaging wise this scope gives perfect round stars to the corners of a 16803 chip which is my usual imaging setup. I have never seen flex or issues with the focuser on this scope which is common with other scopes with modern large cameras like a 16803.

Lightwise the Fluorite lens has almost zero light scatter so delicate hues of reflection nebula or subtle details can be captured that other scopes tend to miss. Colours tend to be richer than FPL 53 triplet lensed scopes as well.

F7 is a decent F ratio to image at and 1260mm focal length suits a lot of targets with a 9 micron pixelled camera or the popular KAF8300 camera for smaller galaxies. You can image galaxies with this refractor as 7 inches of unihibited aperture captures a lot of light and is closer to a 10-12 inch aperture of a compound mirror scope.

Flats are quite simple with this scope as the optics are essentially perfect with Yuri's extremely high optical standards ensuring the highest Strehl ratios similar to Astrophysics standards.

It has a case with wheels that is very secure.

If you are interested PM for further discussion. I would also be willing to deliver it personally within a reasonable distance.

This is a rare opportunity as these scopes come up for sale very rarely and are held onto by their owners.

I can help someone set it up and get the best out of it.

Sample images taken with the scope:


http://www.pbase.com/gregbradley/image/155890887 Wolf Nebula image TEC180

http://www.pbase.com/gregbradley/image/110170343 Horsehead image TEC180

A larger recent image of the scope in action:

http://www.pbase.com/gregbradley/image/154231648/large

Greg Bradley.

[Mizar22 (Santi)]

Hi Greg,
can you contact me?
Thanks you
Santi

[gregbradley]

Replied to Santi.

Greg.

[alpal]

Hi Greg,
That sure is an interesting telescope.
I always wanted to know more about oil spaced lens designs.

I tried to find out more about it on the internet but details are few.
For instance - are all the triplet lenses oil spaced?
Some people oil just two lenses as in this link:
http://users.belgacom.net/astronomy/other.html
- but of course that is just a home made effort & not from a master like Yuri.

Who would be qualified to collimate this telescope if it ever needed to be done?
Maybe oil spaced refractors never go out of collimation?

cheers
Allan

[gregbradley]

Some triplets are air spaced like the Tak TSA models and the AP160. I think some APM lenses were air spaced. Oiled triplets are more common as it gets rid of the need to correct the inside faces of the lenses like the need to be for air spaced. So air spaced would be harder to make.

I suppose there may be some other aspects with air spaced like thermal issues - not sure. AP155 versus AP160 (oiled versus air spaced). There are plenty of top grade AP155 images around. I haven't seen a matching AP160 image but perhaps there are. AP160 is a rare scope.

With the TEC180 its more about the huge fluorite lens. Fluorite is amazing and whilst FPL53 (there is now an FPL55 which is essentially the same colourwise but better for grinding) is much the same the difference is in less light scatter and easier to achieve better colour correction.

The scope is now sold to a US buyer.

Greg.

[alpal]

Originally Posted by gregbradley

Some triplets are air spaced like the Tak TSA models and the AP160. I think some APM lenses were air spaced. Oiled triplets are more common as it gets rid of the need to correct the inside faces of the lenses like the need to be for air spaced. So air spaced would be harder to make.

I suppose there may be some other aspects with air spaced like thermal issues - not sure. AP155 versus AP160 (oiled versus air spaced). There are plenty of top grade AP155 images around. I haven't seen a matching AP160 image but perhaps there are. AP160 is a rare scope.

With the TEC180 its more about the huge fluorite lens. Fluorite is amazing and whilst FPL53 (there is now an FPL55 which is essentially the same colourwise but better for grinding) is much the same the difference is in less light scatter and easier to achieve better colour correction.

The scope is now sold to a US buyer.

Greg.

Thanks Greg,
So the scope is already sold!

I am really interested in oil spaced designs.
Please tell me then - were all the 3 lenses oil spaced or only 2 on the TEC 180?

cheers
Allan