Just seen this on SGL

[Sheila]

I dont do solar but i thought this might be for info for anyone thinking about solar

 

http://stargazerslounge.com/topic/217759-quark-and-cemented-triplets-a-warning/

 

not nice

[red dwalf]

oh dear, i feel his pain

[oldfruit]

Ouch!

[Brantuk]

Yes I saw that this morning - it's a stark warning to all of how wrong it can go and how dangerous the sun is if you don't get solar observing right first time.

[stash]

Better that than his/her eye's 

[Guest devil74]

Better that than his/her eye's 

+1

[philjay]

Yes it is bad luck for the owner but 

I do not really understand the reason why the cement should go manky  .

The danger here is one incident putting folks off from buying a Quark or a solar wedge or even solar projection which has been done for centuries.

Why should the objective get hot enough to melt the cement? Stick a piece of glass out in the sun all day and it wont hardly get warm. Ive done solar projection for hours in the past and nowt gets hot except the eyepiece and my head if Im not wearing a hat.

What was the scope?

What cement was used in the objective?

What were the tolereances in the cell? e.g. were the elements pinched in the cell?

 

Nah, too many variables and questions at the moment to say don't leave an unprotected objective out in the sun I'm afraid.

[+Ibbo]

My guess is the optics where pinched

 

and its just that a guess

[T A WOW]

I'm very surprised by that. Like phil says, glass doesn't get hot, just what it's focused on. The cell would be only 2(ish) inches thick (if that) and in that distance the light wouldn't have been focused much.

Something else must've been going on there.

[Teslar]

Ouch that looks expensive

[Brantuk]

It's been suggested that it could be down to the lens (a triplet) not being air spaced and/or some kind of internal reflection focusing heat on the lens itself. All I know is that it's very wierd and something must've been very wrong with the set up.