i thought i was brave pulling the inferred filter out of my old nikon 950
your alot braver man than me. there's no way i would be doing that to my 60d lol
The replacement sensor for the 450D has arrived. It is obviously brand new with no marks on it at all. Now I have to make a decision: do I cut my loses and just go for the full spectrum mod (removing LP1 and LP2 filters), replace the highly reflective stock cover glass with the MC Clear sensor cover glass and seal it with Argon in that chamber - thus create a dry chamber Version II of my cold finger 450D; or do I try again to debayer the sensor (myself this time) along with the filter and coverglass changes.
I need to re-read all the pros and cons of physical Debayering and work out if the improvement in resolution is worth giving up the microlenses (which have to be scratched off to get to the Bayer Matrix). I will go back and look over my initial mono test images as well (before it was too far gone). Stay tuned.
How much was the sensor Glen ?
I suppose the worse that could happen is you have to buy another sensor if debayering doesn't work. If my latest clean up of the internals of the 450D does not work I may go full spectrum.
That is after I've stripped, cleaned, relubricated and rebuilt the EQ6 and rebuilt my pier to get rid of the Heath Robinson rat cage on top. I wouldn't even dare put a pic up of it in it's present state, I'd get lambasted by one and all. Maybe after ... maybe ...
This is all being brought on by the lousy skies over here at present. Hot and humid or raining. Seeing is rubbish.
Brent the replacement sensor was $38 USD (from China source on Aliexpress) compared to about $85 USD from a Canon spares source in the USA. It's the real deal, all the numbers match, and looks brand new.
I stripped down the mono camera this afternoon and remove the ruined mono sensor. I looked at how I would remove the cover glass from the new sensor and protect the gold wires on the sensor with epoxy which is do-able with some risk (it's nice to have the CentralDS sensor here as an example of how they protected the gold wires) but the microlense removal and polishing off the bayer layer is high risk - I could just wind up back where I was before. I have installed the MC Clear glass in the filter frame where the LP1 used to be, bedded in silicon it will create a sealed chamber in front of the sensor (even if the sensor cover glass is removed and not reinstalled).
Update: So this evening I have taken the plunge and removed the sensor cover glass to gain access to the surface of the sensor. I used my little Hot Devil butane torch and it worked pretty good, hopefully nothing on the board got too hot - time will tell. I have inspected every gold wire connection and they all look good. Next step is covering the gold wires with epoxy to protect them during the debayering. Photos attached.
I've got my fingers crossed for you ...
What are you going to use to polish the microlens & bayer layer off ?
Hi Brent, I have not decided yet, there are a few options. JTW suggests using an APS-C sensor cleaning swab with the microfibre covering removed (in other words just use the flexible plastic end) and dipped in glass polish; some Net uTube people just use toothpicks or cut down paddle pop sticks; I saw one guy that used a Dremel tool with a pointed polishing pad; others use match sticks, etc. I have glass polish so I will use that at some point.
This morning I have started the epoxy process to protect the thin gold wires. First I masked off the surface of the sensor using a rectangle of tape cut to size. Then mixed up some boat building epoxy (International HT9000) with a little glue powder, and dripped that onto the contact area using the shaft of a cotton bud. Had to do some cleanup with acetone so I could remove the tape later. Photo is attached.
It will now sit until the epoxy has kicked and I will pull that tape off at that point. Once it is fully cured I can start on the sensor surface.
Update. I have finished debayering now. It seemed to take a long time but I have polished off the microlense layer and the CFA layer. It's pretty easy to tell when you get to the CFA as the normally white polishing compound started to turn green. It's harder to tell when to stop, so cleaning the polishing tool is important. The corners are really hard to get into, and I have some material left right up in each corner but I think I can live with that.
I reassembled the camera today to do some test shots, leaving the cold finger out for now. I have attached a couple of shots. To me the luminance is improved over the first attempt and that's important, also the uniformity and lack of grainy appearance is an improvement over the CentralDS job. I stopped polishing when I reached uniformity in the Orange/Gold layer and this preserves the luminance, any deeper and your into the pixel surface.
I did not use any scraping, just the polishing by hand and I think that allowed me to control progress better than scraping, and there are less scratches to try and get out. I installed the MC Clear coverglass in the LP1 frame position, and the chamber is sealed with silicon. I cleaned the sensor surface to be spotless (of dust, contaminants, etc) before sealing it up. Argon was put in while sealing it up, and it sat in an Argon container overnight.
I need to get the camera on a scope asap the sky co-operates and check some long test subs. I also need to shoot some flats to see what I am dealing with as artifacts. Zooming in on my test shots from today I can see some artifacts on the flat shot but I think it was (mostly) in the camera lens that I had on the front.
So I think I am getting there.
Disaster! I was taking the camera apart to install the cold finger and that means removing the sensor board. Since I had it out I looked at what I could do about a couple of those artifacts and saw there was a small microfibre hair in the corner inside the cover glass. I decided to remove the sensor cover glass and clean it again. As I was popping the sensor cover glass off it cracked and a piece went onto the sensor surface and nicked it! ARRGGGGG! After all the hard work and care I go and do something stupid that I probably could have just ignored. At first I through I could polish the little nick out but it became obvious it went through the orange/gold surface coating and into the pixel surface underneath. It's tiny but as far as I am concerned the sensor is stuffed. Stupid is the only word to describe how I feel. So another sensor is now junk. I don't know where to go from here, so much effort and so close to success. Very frustrating.
I have another sensor on the way that I had ordered as a backup in case I screwed up the debayering, so I need to consider whether I go through the whole process yet again or just install the backup and be satisfied with another colour camera. I will be considering while the sensor is in transit.
It'd be a shame to give up now Glen, the goal is so close. You should still be able to use the current sensor for testing in the interim, at least it might help you decide how you want to proceed...
Update: The backup sensor has arrived, and looks pristine. I will start work on it tomorrow - yes, I will be debayering another one; after all have made the investment in narrow band filters, and the filter drawer so I should give it a go.
I have also picked up another 450D body off ebay, which I can use as a parts donor or move over to if I have a problem with one of the other cameras. The problem with working on these things is that taking them apart and reassembling does put some stress on the ribbon cables and connectors, so having a body with no 'mod history' is prudent.
Update: The backup sensor has arrived, and looks pristine. I will start work on it tomorrow - yes, I will be debayering another one; after all have made the investment in narrow band filters, and the filter drawer so I should give it a go.
I have also picked up another 450D body off ebay, which I can use as a parts donor or move over to if I have a problem with one of the other cameras. The problem with working on these things is that taking them apart and reassembling does put some stress on the ribbon cables and connectors, so having a body with no 'mod history' is prudent.
I'll hold my breath for you. I'm amazed at how robust they are if you're careful. My 450D must be the most abused, hacked and sacked body ever but it's still going strong despite my ministrations and mods.
Shame the clouds are still over here, I'm all rebuilt in the Ob and got no sky time to align and test.
Two of my modded sensors I had high hopes for, carefully polished surface , gold wires protected with epoxy in advance of the mod, and each carefully encapsulated in tape and earthed on a anti-static mat prior to the mod. Neither is giving me anything, no images from either. I have mod fatique at this point, everything I try seems to make the problem worse.
I am going to give up on making a reliable mono DSLR and cut my losses on this project. I know I have one good spare body and as soon as my next replacement sensor arrives I will install it to make one good standard colour 450D - and leave it at that.
Over the past week's imaging, especially on the NGC5128 Supernova, I am again amazed at the performance of my cooled colour 450D - which allowed me to see the orange colour of the Supernova. I think I need to be satisfied with that camera and not 'focus' on the mono version any longer. Narrowband is probably not as important to me, living in a reasonable dark location, as it would be to a city person; and no real value at places like the Dark Site.
So consider this project closed. I have a set of three Baader narrowband 36mm unmounted filters, and a EOS filter drawer, which I will probably sell in the next month or so to recover some of the money I put into this project. Anyone interested in the filters or drawer let me know.
Now back to spending my nights imaging in glorious colour.
After getting the parametres right in DDS the pixel problem is pretty much resolved, and hey, even new CCDs can have column problems, or so I am told. So it is useable and I have moved on to finalising the camera now.
Installed the cold finger in the Mono camera today, and sealed an argon chamber under the reinstalled cover glass, put the Astronomik MC clear into the filter holder and created a double glazed area in front of the sensor.
Tomorrow I should be able to get the TEC and fan on the finger and run the cooling test. Looking forward to some narrowband imaging.
Finished wiring up the TEC and fan for attachment to the controller, and ran a preliminary test today. I should point out that at this point the cold finger is not insulated with foam sheet (as is my usual practice), but does have the Plastidip coating. Starting point was ambient 20C and humidity was 40%. On controller startup, with camera powered up, the temperature dropped rapidly, in about four minutes reaching its set point of -7C; which is a Delta T of -27C from ambient. This is a good result and in line with the same test of my original colour camera test. Ran some Offset/Bias frames at 1/4000th of a second, and then did a couple of three minute darks at ISO1600, they look identical when stretched.
I have attached a couple of pics of the mono camera under test, notice the frost build up on the cold finger.
Looking good for on scope testing soon.
Mono DSLRs are all about the filters and how you manage them. Given the backspacing requirements of the Canon APS-C sensor, I chose the Teleskop-Express EOS 36mm Filter Drawer device:
It allows me to use my current T-Adaptor and I got the 36mm filter drawer sent with it (ask on ordering as they can swap the standard 50mm, and 36mm filters are slightly cheaper and provide plenty of field for the APS-C sensor).
The issue that arises from putting a filter drawer on the front of a cold finger cooled DSLR (one that is using a dry gas purge system) is how do you prevent the loss of your gas and the internal condensation that might result. On the colour DSLR I just stick a Baader UV/IR Cut filter on the front of the T-Adaptor and it's fine, but on the Mono the filter drawer will leak and so needs a gas barrier behind it.
My solution was to use an Astronomik MC Clear EOS Clip-In filter to create the gas barrier. Normally a Clip-In filter is a press fit into the mirror box opening but to seal it I used black polyurethane on the outside ( the idea being that I can remove it if I had too in the future). Importantly, that MC Clear filter must be spotless before you install it because it is not a casual removal to clean it. Obviously don't get any sealant on the outside surface of the MC Clear as it will be hard to clean off.
Now the Filter Drawer can be used without loss of the internal dry gas, and stops any dust from getting into the shutter area from the aperture of the camera. You can always clean the outside of the MC Clear when required.
Photos attached.
there's no way i would be doing that to my 60d lol
