Thermal Camera - The AGA 680 Thermal 15X Microscope - retro tech porn - Page 1
Forum section: electronics / testgear

author: Fraser
author_rank: Super Contributor
timestamp: February 23, 2015, 11:12:30 pm
content: Those who know me will be aware that I am a long term user, collector and repairer of thermal imaging cameras. This thread details my latest acquisition..... the AGA 680 Thermal Imaging microscope !AGA is the forefather of Agema who became part of the much respected FLIR thermal camera manufacturing company. Medical and Industrial applications for thermal imaging include the use of thermal microscopy for examination of very small targets. AGA produced the 680 camera system in the early 1980's for medical and industrial use. You may be assured that the cost of the system would have been truly eye watering !The thermal camera is a scanning mirror based unit that uses motorised mirrors to create a raster image using only a 1 pixel liquid nitrogen cooled thermal sensor. Scanning systems were common and standard in the thermal camera market place in the 1980's. They may sound very Heath Robinson like the early mechanical raster Televisions, but they are in fact precision machines that made thermal imaging possible in an era when even a single pixel sensor cost a small fortune...staring array technology had yet to be made. Liquid Nitrogen is not uncommon in industry and medical institutions so was not considered a great disadvantage. A very different situation for the home user however ! Your average Jo would not have had the finances for such a purchase though.The 680 is the main camera cylinder that may be fitted with a variety of large aperture lenses and the specialist microscope head. The Liquid Nitrogen is poured into the top rear mounted port that may be seen in the pictures. The Vacuum Dewar contains enough Liquid Nitrogen for a 4 hour operating time before a refill is needed. The 680 camera passes its scanned image data to the control and display unit via a long umbilical cable. Due to size and weight the 680 is normally operated on a tripod or desk mount. The microscope version of the 680 would normally be mounted on the test jig that is used for sample inspection. The microscope head contains both an optical and thermal microscope lens structure. The optical microscope is used to align the sample correctly. The thermal lens is then moved into position on a slide assembly and the thermal images captured. The microscope provided 15X magnification.The camera also contains a number of specialist thermal imaging filters that may be placed in front of the thermal sensor. these include a 2000C range extender, water imaging filter, sunlight filter and various attenuation filters. These filters are all designed to be user removable and sit in their own individual filter holder modules.Why did I purchase it ?1. It has a very rare and useful thermal microscope head that would cost a small fortune to purchase today. Perfect for in depth PCB inspection.2. I collect thermal cameras of all ages and types3. I suspected the unit would sell cheaply as there is no controller and it is old.4. It was located less than 1 mile from my homeThe unit sold today for GBP35 and I collected it this afternoon.I have quickly opened the unit to see what lives inside. as expected the build quality is similar to that found in military equipment. Built like a tank and of very high quality. Cables are neatly laced, the chassis is large and heavy providing rigidity, the optical path is enclosed in machined aluminium modules, the motors are superb quality and the gearboxes use metal precision gears and clutches. Hmmmm nice engineering.Now this camera will never be returned to service and is just a sample of the technology for my collection. I don't bother playing with Liquid Nitrogen these days.... nasty stuff if handled or stored incorrectly. Now the microscope head.... that is a different matter. It is a LW lens assembly and so may be used with my industrial FLIR thermal cameras. I hope to use it as a thermal camera microscope again for PCB and other work, such as thermal imaging of insectsTime for the pictures......

author: Fraser
author_rank: Super Contributor
timestamp: February 23, 2015, 11:12:59 pm
content: Images

author: Fraser
author_rank: Super Contributor
timestamp: February 23, 2015, 11:13:23 pm
content: Images

author: Fraser
author_rank: Super Contributor
timestamp: February 23, 2015, 11:13:48 pm
content: ImagesNote I have not cleaned the lenses yet so they do have muck on them from storage.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 24, 2015, 12:11:15 am
content: I had my eye on this but got distracted & forgot... guessed it was probably you that got it

author: Fraser
author_rank: Super Contributor
timestamp: February 24, 2015, 12:47:58 am
content: Oooops Sorry Mike,I offered the seller GBP50 last week as soon as he put it up for sale. He declined. I guessed it would appeal to a very restricted market (likely only you and me) so did not expect it to sell for a great deal. I would have gone to GBP70 for the lens alone though. The seller is actually a recycling company called 'WEEE STOP'. They have branches around the UK. They had no idea what the unit was or what it was worth. They just stick it items on ebay and they find their market value. They stated 'collection only' on this item and did not seem the most flexible of companies to deal with. They are just up the road from me which made this a particularly attractive auction as the unit is heavy.It has some nice Germanium optics in it. None of this cheap GASIR glass stuffThe item I listed as the 1st scanning mirror may not be a mirror as it appears to be Germanium plates on a drum or a six sided large Germanium prismIt is also in the wrong place to be a mirror. Mirror scanners place the first scanning mirror far back in the optical block and it reflects the image onto another scanning mirror closer to the front of the camera and facing its partner. A spinning mirror right at the front of the optical path makes little sense. A spinning prism though....that could be a possibility. If it is a prism, it is one heck of a chunk of Germanium ! I hate to guess at its production cost.I need to do some more research on these early units.If the unit does not suit my needs I will let you know.Aurora

author: Fraser
author_rank: Super Contributor
timestamp: February 24, 2015, 11:21:09 am
content: Thermal source for calibration & reference - designed for the 680 cameraBy pure coincidence the thermal reference source (Black Body) that was built for the AGA 680 appeared on ebay USA the other day. Needless to say it is now winging its way to me in the UKThe AGA Black Body produces calibrated temperatures between 16C and 100C which will be very useful when I am testing and assessing thermal cameras. I already have a more modern Black Body source but that tops out at less than 50C so the AGA source will extend that range for me.I am not familiar with the internal design of this unit so will be taking it apart as soon as it arrives. I can see that the source head has a fan in it but no idea what the heat source is. Peltier ? Watch this space.It's a multi voltage design as well so no need for a step down transformer in the UKNote the 'AGEMA' labels stuck over the original AGA markings on the rear panel. This unit must have been produced just after AGA became AGEMA.Pictures from the auction attached

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 24, 2015, 11:53:17 am
content: Quote from: Aurora on February 24, 2015, 12:47:58 amIt's the place I got the blood analyzer from - I did try making them an offer on the Mass Spectrometer they had when I was up there, but they seem to prefer to leave things to run.QuoteI was really only interested in it for teardown curiosity, and you've satisified some of that with photos!

author: Chanc3
author_rank: Frequent Contributor
timestamp: February 24, 2015, 03:23:04 pm
content: Interesting stuff! I was very interested in putting a bid in for this, but then I spotted it was collection only and I live about 5 hours drive away!Glad someone on here picked it up, and even better to see the teardown! Good work!

author: Fraser
author_rank: Super Contributor
timestamp: February 24, 2015, 03:59:04 pm
content: I will be digging deeper into the optical path in due course so I will be able to upload more in depth pictures for you to puruse.These very early cameras are more curios and collectables than practical instruments but the optics are often as good as, or superior to, modern assemblies, so well worth looking out for.Aurora

author: 3roomlab
author_rank: Frequent Contributor
timestamp: February 24, 2015, 04:03:26 pm
content: wow, i guess this is what biologists use to capture heat given off at cell level? the sensor must be very very sensitive?

author: bookaboo
author_rank: Frequent Contributor
timestamp: February 24, 2015, 04:13:06 pm
content: What's the plan for the microscope part? Will you be pairing it with a sensor salvaged from another unit or will you be able to make a bracket/stand that can hold an existing camera in place?

author: Fraser
author_rank: Super Contributor
timestamp: February 24, 2015, 06:22:54 pm
content: @Bookaboo,No plans set in stone yet. I have several thermal camera cores that could be mated with the microscope lens. Mating it with the objective of a thermal camera may be a challenge if I do not have the appropriate optical interface.This will be a little project for me when I have a spare momentAurora

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 24, 2015, 06:29:16 pm
content: Quote from: Aurora on February 24, 2015, 03:59:04 pmPresumably there is the question of the wavelength that the optics are coated for - I'd assume anything designed for a cooled sensor wouldn't be any use for a modern microbolometer

author: Fraser
author_rank: Super Contributor
timestamp: February 24, 2015, 06:57:32 pm
content: AGA used both cooled SW and LW sensors. The optics for this 680 unit were designed to work with either bandThe Inframetrics 525 is the same and can even have SW and LW sensors in one camera sharing common optics.Agema did the same with some of their camera lenses as well. It is not uncommon to see band specific lenses though, as you indicate. The Agema PM550 is an example of such. Its lenses are SW only and perform poorly on a LW camera. I tested this and Agema even made the auxiliary lens mount different to that of the LW thermal cameras to avoid user error.Aurora

author: Fraser
author_rank: Super Contributor
timestamp: February 24, 2015, 11:16:32 pm
content: I have extracted the catalogue image of the AGA 680 microscope complete. It is attached.

author: Fraser
author_rank: Super Contributor
timestamp: March 16, 2015, 06:15:22 pm
content: Whilst researching the 680 design I have found a description of how such a unit works. It is based on the scanning principle using Germanium Prisms rather than mirrors. It must have cost a small fortune to produce. The data is for another AGA camera of the same period but I have confirmed that the principle of operation is the same.Images attached

author: Fraser
author_rank: Super Contributor
timestamp: March 17, 2015, 02:02:39 pm
content: Well the thermal microscope is off to pastures new. I received an offer for it last night that I cannot refuse. A company in the USA still uses these things and needs my unit for parts. Its going to serve them better than me so a no brainer.Aurora

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 17, 2015, 03:05:11 pm
content: I hope you checked that their offer was more than the scrap germanium price, which AFAICS is of the order of a pound per gram

author: coppice
author_rank: Super Contributor
timestamp: March 17, 2015, 03:20:48 pm
content: That machine looks very similar to one I used to use, but it would have been in the late 70s, not the early 80s.

author: Fraser
author_rank: Super Contributor
timestamp: March 17, 2015, 04:09:06 pm
content: Mike,Thanks for the comment. I do not really understand the trade in scrap Germanium.....who actually reuses the stuff ?. At the market value you state, unless there is more than 4000g of Germanium in the lenses and Prisms, I think I am getting better than scrap valueI do need to do some checks for any export restrictions on this very elderly unit before shipping it though.Aurora

author: coppice
author_rank: Super Contributor
timestamp: March 17, 2015, 04:12:47 pm
content: Quote from: Aurora on March 17, 2015, 04:09:06 pmWhy wouldn't people reuse germanium lenses? Its cheaper than refining new germanium.

author: Fraser
author_rank: Super Contributor
timestamp: March 17, 2015, 04:20:26 pm
content: Its not a material that I considered taking t a scrap merchant. I have a lot of Germanium in old thermal camera lenses. I presume that there are specialist dealers in such scrap who know how to treat and market it for re-use. Something I should look into. Thanks.Aurora