How to tell if its a genuine TMB planetary?

[sharkbite]

Hi folks -

I am looking to buy a 9MM TMB planetary, due to it being relatively cheap and getting rave reviews all over the internets...

A local supplier reckons TMB don't make em anymore,
so can't get em - and also to beware of "fake" ones being sold on ebay.

Also, allegedly there are 2 types of genuine TMB - one manufactured by Mr Bell, and another by Mr Burgess...(or so the internet says)

My question is:

Does anyone know how one tells the diffference?
Is there a marked difference in performance?

[slowflow]

Maybe CN forum can help

[Profiler]

Although I can't warrant this suggestion I have observed one rather simple distinction. There are heaps of clones/copies of the TMB/Burgess planetaries but from what I have often observed many of them they don't actually label themselves as TMB. They may have the same diamond artwork and numbers painted on them but they don't actually feature the words TMB/Burgess

[Wavytone]

Burgess optical are the real ones.
TMB stands for "Thomas M. Back" who was the optical designer for Burgess.

Steer clear of eBay, if you want these secondhand, look on CloudyNights or AstroMart.

[dannat]

if you look at the authorized versions being sold by Astronomics, the focal length lettering is in the middle of two bands of rubber diamond grips and "mm" is in lowercase, and the barrels are shiney black and undercut. In the knock-offs I have seen the barrels are a satin black, have tapers, and the focal length is printed below the rubber grip panels and is in uppercase "MM". Astronomics are licensed by the family (t.back has passed) to sell the ep's

For a short while Burgess sold the Type-IIs before the estate took control, those versions all have "Burgess/TMB" on the label someplace and I would consider these authorized as well. I don't "believe" any of the knock-offs had Burgess on them anyplace.

they were designed by tmb -but made in chine -initailly when he was alive they sold the knock offs as planetary -not hey label them as tmb planetary, using the name is the problem

fake in pichttp://www.cloudynights.com/ubbthreads/attachments/4975389-TMB_II_Clone.jpg

[Wavytone]

Ah yes something else about that clone - it bears the markings "SW" (super wide). The real TMB planetaries were a modern variant of the monocentric design, so the field of view is narrow - definitely not superwide.

To make it all the more confusing TMB did also make superwide eyepieces, the Paragon 30 and 40mm which WERE designated "SW".

[rmcconachy]

I think you may be confusing the TMB Planetary oculars with the TMB SuperMono (http://www.cloudynights.com/documents/tmb.pdf) line (both were designed by Thomas Back)?

[sharkbite]

Thanks folks will look out for the real thing....

Is there a great deal of difference in actual performance though?

[Don Pensack]

The original TMBs were, if I recall, 6-elements in 4 groups.
The TMB look-alikes (most made by Barsta) are usually 5-elements in 3 groups.
The ED eyepieces like the Astrotech Paradigm, Orion Epic-II ED, Telescope Service ED, etc. are probably closer in performance, with 6 elements in 4 groups and pretty good inexpensive eyepieces.

[Merlin66]

There was a LONG illustrated thread on TMB eyepieces over on SGL
Worth checking out...
http://stargazerslounge.com/topic/134974-tmb-planetary-originals-vs-type-iis/?hl=tmb+eyepiece#entry1983180