I remember reading a similar story in Telescope Making magazine back 20 or 25 years ago involving the very experienced U.S observer and telescope maker Tom Clark (the first amateur to make a 36" -- the "Yard 'scope").
At the time of the incident, he was observing with a 17.5" Coulter Odyssey Dobson mounted Newtonian. After a night of observing he left the 'scope outside until well after dawn. As a result, it was heavily coated with dew in the morning including a very wet primary. In order to quickly dry the mirror before packing the 'scope in the car, he pointed the telescope so the sun was shining down the tube illuminating the mirror. He went away to pack some other things into the car and when he turned back to the telescope a few minutes later, the whole top of the sonotube telescope was ablaze.
Being in the biz you'd think he'd know about covering a large mirror. I remember a photo of a C11 fitted with a diagonal left on an appartment balcony. All was left were the tripod legs and the OTA. Everything else was torched.
We have a collection of all different sized stainless bowls and my wife uses one of them to collect vegies from the garden.
Last summer we could see smoke coming from behind the kitchen.
As we lived in the bush, panic stations kicked in and im already running to the fire pump.
My wife came around the corner with the large bowl ( about 40cm) with a cloth in the middle smouldering away.
We then tried a few more bowls but it was only one thst could ignite paper in about 30 seconds.
This bowl is now banned from our bush block and im still worried with it in the kitchen at our new house.
Pretty scratched now so the mirror effect is not as good but im still worried.
I never thought about putting a secondary and eyepiece with the bowl.
Hmmm a parabolic for $10......bargain
Cheers
Andy
..... oooh 
I remember a photo of a C11 fitted with a diagonal left on an appartment balcony. All was left were the tripod legs and the OTA. Everything else was torched.
