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Broken Diagonal


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Last night my nice televue 1.25" diagonal decided to drop out of the telescope onto concrete slab below:(. It has a big chip in one edge of the mirror. So two questions

do you just replace the whole thing or do you get replacement mirrors (at a reasonable price)

what can I do to avoid it happening again, apart from making sure the screw is done up tight?



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Looks like a replacement unit is in order. If the mirror is still held in place (just cracked) it would be interesting what the effect on the views were. It might be that for faint objects you won't notice any difference.

My 2" diagonal did not have a safety groove in it, so I used a metal file to cut 2 small grooves in it that the locking screws can 'bite into', so the screws cannot work slightly lose and the diagonal fall out.

You didn't mention any eyepiece damage, so you might have escaped with less damage than possible.



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there is a company that sells mirror plates for diagonals, not that expensive from what I recall. I guess it somewhat depends on the quality you are after, you could get a replacement mirror for £10 or so but it won't be a Televue or up to that standard but it may do for a while until a permanent replacement is secured. Galvatronics is the company, just google them.

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Sorry to hear of your little accident.

I'm not sure get anything like the performance out of it that you were used to unless the mirror is replaced by Tele Vue I reckon ..... the mirror will have to be precisely aligned in the body of the diagonal, of the same quality as the original (you did not say if it was a dielectric or not ?) etc.

Personally I would be having a look at my house contents insurance and see if I can get a replacement ..... just my opinion.


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thanks for the comments. The views aren't too good, there's a big black blob on one side of the image, it's still just about usable but quite annoying.

Fortunately the eyepiece survived and I bought the diagonal second hand so I haven't lost that much, it could have been a lot worse.

It's made me think twice about splashing too much on eyepices though. If I had had an ethos when the accident happened I would be pulling my hair out now!

I think I'll pick up a parfocal ring, put it on on diagonal and tie some cord between the ring and the shoulder of the diagonal. I'll loop the cord around the focuser to stop it hitting the ground if the next one falls out!

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