TMB Planetary II EP light tails

[glend]

Can anyone tell me why my TMB Planetary II 9mm EP is displaying tiny light trails behind stars in the field.

While observing tonight, using my 12" GSO Dob, I used various EPs, including the GSO Superviews in 30mm and 15mm, as well as my 9mm GSO Plossel, all of these were the usual perfect view with no distortion or light tails, flaring, etc. But when I put the TMB in the focuser it exhibits tiny trails on each of the stars in the field mostly pointing away from the centre of the field, it's also hard to focus. Why is this so, and what could of happened?

When I first got the TMB the view was great. What's changed? I did collimate the scope with my laser, but each of the GSO EPs are great and the collimation seems spot on.

Any ideas?

[brian nordstrom]

:shrug: Hate to say it Glen but it sounds like this eyepiece has a fault , looks like something has moved inside throwing off the optical axis ?

Where did you get this one , local ? and if so take it back , most retailers will do a replacement without any fuss .
But I have never heard of an eyepiece being Ok and then suddenly having major 'Coma' all of a sudden :question: , that's what it sounds like from your description .
Good luck .
Brian.

[omegacrux]

Glen
I noticed my tmb 6mm was rattling when shaken
Fiddled around with it ,
and it was slowly un-screwing itself , at the top
Sinched it up finger tight and it's right now

David

[glend]

Thank you for those suggestions. I bought it off ebay from a UK astro store. It worked fine the first tme I used it but this last time it was terrible. I noticed that the wider top section turns as if it had a zoom or something. I will try to tighten it up and give it another go.

[Steffen]

The top section is actually an adjustable eye guard. It does screw off altogether eventually, at which point you'll have access to the top ring that holds the optics together. Maybe that one is loose?

(That's from memory, I haven't got TMB Planetaries anymore, YMMV.)

Cheers
Steffen.