TMB Planetary Eyepieces, Genuine vs UK Sourced

[cs1cjc]

I have in front of me two Planetary eyepieces. One is a genuine 4mm TMB Planetary II eyepiece as authorised by TMB Optical and available from Astronomics and Highpoint Scientific in the US, which I have just bought (at some expense!). See:

TMB Website

TMB Optical Planetary 4mm long eye relief 1.25" Eyepiece TMBP04 | High Point Scientific

The other, also 4mm, was sourced in the UK about a year ago and is similar to all those I can currently find on UK supplier web sites.

The eyepieces are, so far as I can tell, made to the same optical design. I have not yet had an opportunity to test them against one another, but the differences are more than skin deep as is shown in the attached photographs, in which the genuine eyepiece is on the left in each case.

TMB is not a registered trademark in the UK but is still likely to be protected, see for example:

Passing off - Wikipedia, the free encyclopedia

[Merlin66]

Chris,

You've lost me a bit...where does it say TMB on the second eyepiece?

[jnc71106]

in the middle picture it has tmb optical near the top above where is states sw 4mm of the right hand eyepiece

[cs1cjc]

Chris,

You've lost me a bit...where does it say TMB on the second eyepiece?

Apologies. This should make it clear

[michael.h.f.wilkinson]

The lettering on the "non original" looks a lot like that on my Burgess-TMB optical Paragon (down to the MM). This was certainly an original (I have all the paperwork), made by Burgess Optical.

[Merlin66]

My 7mm TMB Optical looks different again!

It is very similar, barrel shape and body shape to the one you show on the left, but the rubber knurled portion is wider and "TMB®Optical" and "Planetary" are engraved on the bottom ring. I doesn't have a twist up eyecap. (Note: doesn't say Planetary II)

Another variation??

[jnc71106]

These eyepieces confuse me far to much so I stay away from them

seems to be a can of worms whenever a thread about originals and clones is started

[cs1cjc]

These eyepieces confuse me far to much so I stay away from them

seems to be a can of worms whenever a thread about originals and clones is started

You are wiser than I have been because I have four UK sourced ones. I certainly feel I can no longer recommend them, but it is a pity. These are essentially well priced, lightweight, simple (5 lenses and 6 air to glass surfaces except for the 9mm which has 6 lenses and 8 air to glass surfaces) eyepieces with a flat field and low distortion, in a decent range of focal lengths. In a number of respects they remain unique in the market. There are also enough good reports for me to believe that bad reports are more likely to do with production and quality control issues than inherent problems with the optical design.

[Merlin66]

I find the 7mm TMB absolutely great on my white light solar scope with a Herschel wedge!!

[Caldwell 14]

Well I was thinking about buying a set of these from skies the limit, perhaps not then, what are the BST explorers like? same issues ?

[jnc71106]

From what I've read on here the bst are the better eyepiece. Ive seen both and the bst's are certainly better build quality IMO