What could it be...

Tricky one. It looks, from the top of the damaged area, like 'something' went in, but the lower margin suggests 'something' coming out.

My first guess is a (very) pointy umbrella; my second, lightning.

Old box camera, the flash got a bit close

Regards JD.

alright, clearly you have identified the iris, that is the easy part... the parts pictured here are of substantially heavier gauge then an old camera would likely have, and the materials are all contemporary alloys (sorry, I don't know the specific alloys, but mostly steel and not too exotic)

Early lime-light spot got out of hand?

Not lime-light, and not really out of hand, more out of whack

The aperture of an old movie projector.

The beam rectifier or reflector was damaged and concentrated the light beam (from arc lamp) at the wrong spot.

you're on the right track, if I was a generous soul I'd give it to you but then my fun would be over... between you and JohnDG this mystery won't last much longer

Just a couple of observations:

First is the discoloration around the aperture. The discoloration appears to be ellipitcal, and centered on the damage.

Second, the aperture appears warped at its top.

The only firm conclusion I can draw from this is that the damage was caused by heat. I can offer no speculation about the cause of the heat, unless the operator was taking pictures of a burning thistlewick, and got too close.

Heat is definitely the cause of the damage, when you know the source of the heat you will have the answer...

Camera pointing into the sun, or should say just off center of the sun. -- JHF

It seems like a diffuser section of a small gas-fired burner. in the centre you can see the tip of the gas nozzle and the diffuser is there (behind this will be the air blower) to give a swirling motion to the flame. The front part of this will be a cone to entrain the flame which is missing.

The damage to the diffuser is high flame impingement due to some fault in the exhaust

or maybe due a burner backfire.

No gas, and no fire (unless something has gone far more horribly wrong then actually happened here)

Looks like the cooling fan quit.

It is an intense light beam from the inside that was aimed incorrectly.

Maybe a photographic enlarger?

It doesn't involve photography, but your initial assertion is correct.

Okay.

We have a shutter, an iris, a source of heat and a non-normal function.

Judging from the heat discoloration of the shutter and the damage to the iris, the heat source has substantial energy available that is not normally handled by the shutter or the iris.

The pattern of the heat discoloration to the shutter suggests that it occurred with the shutter nearly closed, probably by getting out of time or failing to open at all.

The damage to the iris is off-center and is localized, not involving the entire iris, and would appear electrical as the plates of the iris repelled each other.

I am leaning toward a sensor, scalable with the iris, normally protected by the shutter in the closed position, and an unusual electrical discharge that found earth through the shutter to the iris.

We have a shutter, an iris, a source of heat and a non-normal function.

Yes

Judging from the heat discoloration of the shutter and the damage to the iris, the heat source has substantial energy available that is not normally handled by the shutter or the iris.

The available energy was unchanged from normal, though the energy at the iris and shutter was in excess of normal operating levels, which caused the damage

The pattern of the heat discoloration to the shutter suggests that it occurred with the shutter nearly closed, probably by getting out of time or failing to open at all.

The shutter was operating normally, though normal operation frequently leaves the shutter closed more often then open

The damage to the iris is off-center and is localized, not involving the entire iris, and would appear electrical as the plates of the iris repelled each other.

The iris/shutter assembly is not powered and was not energized prior to, during or as a result of the damage

I am leaning toward a sensor, scalable with the iris, normally protected by the shutter in the closed position, and an unusual electrical discharge that found earth through the shutter to the iris.

A nice guess, but sadly off target

I will post the answer tomorrow evening. For those who can't wait... let me know and I'll send you the answer. There are enough hints between the thread and my profile (hint hint) that an acceptably close guess can be made without knowledge of the specific device (though even that has been fairly clearly identified through the course of this thread... you just have to know where to look and what bits to put together)...

Good Luck and good fun

Another guess, maybe a stage spot light operating from the back of the hall, the light has to be strong enough to reach the stage and controllable, on/off and size? during normal operation the light source short circuited, producing excessive heat and consequently the damage?

Regards JD.

You are right about everything but the short circuit theory... Everything electrical about the device was operating properly.

This is some form of theatrical lighting. Behind this iris, (the side we see here), is a high power light bulb. I would say the elements in this bulb resides in a vacuum. I would also guess that this glass type envelope, (perhaps a quartz glass), was compromised. This would cause the element to burn up quickly, at a very high temp, causing the damage.

OK, that's the best I got.

Yes. Yes. Yes. Yes, no. And yes but no...

A very good assessment, and an entirely possible diagnosis... just not the case this time

I made an error here... the elements are not in a vacuum but are in fact under several atmospheres of pressure... this is not however relevent for the particulars of this case...

One assumes a very strong light, generating a lot of heat? therefore as a consequence the iris would get quite hot, it then follows as this is used in a darkened hall insects such as moths might be flying about, and attracted by a small light in the centre of the iris, lands on same, sizzles, causing the damage?

Regards JD.

Very true, there are lots of sizzled insects in my world... but alas, none here...

It is a fairly strong light, and it does get hellishly hot...

Is it a carbon-arc lamp? Was the carbon rod misaligned and it touched the iris?

Not a carbon arc lamp and there was no physical contact with the iris...

Mis alignment of the light beam and instead of being centered, the beam focussed off center.

that is pretty accurate, though the beam was more than just off 'center' as I will reveal in a few hours.

I see in front of the iris two strait edges, top and bottom. These are possibly for holding different coloured lenses, therefore for my next guess, I would say that one of these lenses focused the light back on to the iris or alternatively, the lense was of such a material that it caught fire?

Regards JD.

the straight edges are a shutter, but you're on the right track with the idea that the light was inappropriately focused...

It is frustrating to almost know what is inside and what went wrong but not able to recognize the equipment.

A arc, laser or filament light source would all be able to cause damage if the reflector or lenses are damaged.

The iris will not be used to control the light beam but maybe only to stop stray light from exiting in the wrong direction.

My guess now is an instrument used to send a concentrated light beam into space where it will be reflected and measured. Maybe from the moon.

Or - (Under several atmospheres) - Under ocean spotlight. (used for filming Nemo)

As has been suggested in earlier posts, this is a theatrical lighting fixture, and it does have an arc lamp...

the reflector and lenses were not 'damaged' prior to or after the iris damage (which probably occured over several hours)

The iris is specifically used to manipulate the light beam

Your guess is, in a poetic sense, exactly right... though the space is largely imaginary and the measuring instruments paid for the illusion...

Did it get pointed at the sun by mistake?

Thats my guess too....

the damaging 'energy' originated from within the device

Looks to me like a carbon-arc follow spot.

it is a follow spot and it does use an arc lamp

Must be a xenon arc. Did the lamp blow?

it is, but it didn't

OR, did the lamp shift or come out of it's mount?

nope, but the effect you are thinking about is accurate... I'm going to post the answer at roughly 5pm MST (00:00 GMT)

From what I'm seeing, the plate on the exterior that appears to me to be mechanical based on the linkage on the right was in the closed position while the unit was left on too long, the heat/light source is mounted near the position of the damage. I have no idea what this piece of equipment is though.

Someone sprayed WD40 or sim onto the sticking iris while the lamp was lit and it (WD40) caught fire.

Stu.

OK, you got me rolling around with laughter on this one, but only because it has such a clear ring of truth to it... that is definitely the kind of bone head move you can expect from more than a few stage hands... the old anything can be fixed with duct tape, bailing wire or WD-40 philosophy is still running rampant in this business... If some bozo had sprayed WD-40 in there while it was running it would likely lead to a major fireball and a crispy spot-op not to mention a glass handgrenade exploding in the midst of high voltage DC wiring just the other side of a thin metal box...if they did it while the fixture was off (and cool) the next time it was turned on it almost certainly would have caused at the very least a huge noxious cloud of smoke and would most likely have ruined the iris...

I'm giving you a GA even though you're wrong because it's important for the thinkers of the world to remember we're surrounded by 'un-thinkers' (un-thinker: noun, a word I just made up to describe those amoung us who would rather bang their head on the door then think of a way to open it... like turning the knob)

As a great philosopher once said, "You can't fix stupid".

No-one has mentioned the word LASER. Surely if we are talking serious heat generating power and optical systems a laser is the obvious source? Still don't know what caused the failure though.

My guess is a Lazar that reflected back and damaged the iris

just regular light from a fairly conventional source

This appears to be an iris from an Archimedes death ray as shown last year on Mythbusters.

it's actually a related device, the Archimedian Portal of Righteous Chancres and Demonic Infiltration... It's just that the last chancre through the portal missed a little low and to the right thus thwarting the demonic overthrow of our plane... it was all over the news

I googled Hairlesssimian and in his blog, found that he is involved with theatre technology. Therefore, I would venture that the device pictured was a theatrical spotlight, damaged by some accident (overheating?). Such spotlights require modication of the beam, such as with an iris, and a previous suggestion that the device can hold colored filters also supports this possibility.

It is a theatrical spot light and you are certainly on the right track. It can hold colored filters (we call them 'gels'; the original methods of coloring light were to use either colored glass or gelatine... gelatine is much cheaper and doesn't slice open Puck's foot in the second act... sorry, non-sequiter) and there is definite beam modification going on...

I'll guess that the lamphouse shifted, causing the focus to shift to the side from the usual center to the iris. (Or perhaps the last bulb installed was never correctly aligned.) Alternatively, the bulb holder became dislodged, putting the bulb against or very close to the iris.

perhaps the last bulb installed was never correctly aligned

this is essentially correct, though this fact is primarily responsible for the location of the damage it is not the reason for the damage occuring... it just helped some, I've got another one with the damage nearly perfectly centered around the iris, the difference being that the lamp was properly positioned... If I say more I'll give away the whole farm but I will elaborate (with poorly executed illustration) when I reveal the whole answer...

The unit was operating at a outdoor music festival somewhere in Ohio, on a warm summer evening with electricity in the air. Just as <insert band name here> took the stage, a few small droplets of water began to fall from the sky... Shortly after the lead guitarist began his mind blowing solo, in the midst of numerous flash bulbs, fog machines, a few pyrotechnic explosions, no one seemed to notice the small lightning strike that entered through the "b" string on the telecaster, continued through the 1/4" guitar cable, backtracked through the soundboard which was sitting directly next to the lightboard... The arc of lightning then jumped to the "spotlight #7" main fader, found it's way through the 150' "spotlight #7" control cable, and right up to the light itself, causing untold (but easily seen) damage to the iris/shutter on the light...

yes?

We installed a shunt between the guitarist and all the rest of our equipment specifically to prevent this situation from happening... crappy bargain bin electronics have failed us again...

.It uses a Mercury arc lamp High voltage flash over??

I think you just forgot to turn the lamp off when not in use those lamps produce an awfull lot of heat.

other than that a bird flew into the turbine

two birds and a flying pig...

oh no..... the end is near! flying pigs, its an omen.

well, it's been fun, but I suppose it's time to let the cat out of the bag...

The pictures are of an iris and shutter assembly of a theatrical follow spot. It uses a 1600W xenon arc lamp positioned within a parabolic reflector that focuses the light to a point just in front of the iris after which the beam crosses itself and begins to expand again. After passing through the iris the beam then passes through a series of lenses to achieve the proper beam diameter and 'edge' (the edge of the beam can be soft and fuzzy or crisp and sharp depending on the relative positions of the lenses)

Pardon my mediocre drawing skills, but here is basically what should be going on...

The lamp's position can be adjusted (in or out and in a small circle perpendicular to the beam direction) within the reflector to optimize the beam and center it.

In this case the lamps position was off, moving the 'hot spot' down and to the right; and the iris assembly was positioned too far back so that the focal point was almost right on the iris thereby creating unusually high heat on the iris which caused significant damage making the iris inoperable.

Aside from the sudden lack of function on the iris the other symptom that clued us in to the problem was that when we put gel (colored plastic sheets) in front of the light it would burn a hole through it in 1-2 seconds, normally these gels last for a couple hours of exposure before the color begins to bleach out and then usually another hour or two before holes start to form.

Thanks again for playing and I look forward to be challenged by you in the future.

Thanks, Monk,

This one was fun.

I knew it was a spot lamp, but I couldn't figure , for the life of me , how someone could ****it up so completely. I had thought that they were essentially foolproof. I should have known better.

Thanks again,

Stu

I was too late to contribute but now that people know what happened, are they going to change the design so it never happens again?

Or is this a case of "Don't change anything! We'll make money on it!"?

regards,

Vulcan

I think it's more a question of "Who-dun-it?".

Was it supplied faulty? Were the instructions for setting it up inadequate? or ignored? Did whoever set it up know what they were/should have been doing? Was it moved by an accidental jolt, maybe by someone who didn't realize the consequences (or didn't care), and so didn't tell the lighting technicians?

If this was a common failure, surely people would stop buying them, and go to a supplier who made good'uns?

In this case the fixture was mal-adjusted when it left the factory... the basic design is fine, assuming everything is properly tweaked and when I called the factory to report the issue they were dumbfounded for a while because this is a very rare set of circumstances and they replaced the damaged parts free of charge... I seriously doubt they will modify the design signifcantly because the retrofitting would likely cost as much or more than just replacing the occasional iris...

Thanks for your interest,

J

Thanks for the fun.