Building Camera - Advice on CCD Imager
Posted 20 May 2013 - 09:19 AM
To start with I want to find a chip with smaller pixel size because my refractor is only 632 mm focal length, and I would like to sample at about 1"-2"/pixel, which means the pixel size needs to fall between 3 - 6 microns square.
The Kodak 8300 would probably work (5.4 microns), but are there any others (monochrome) in that size category with higher QE?
... And maybe cheaper too?
Posted 20 May 2013 - 09:50 PM
An ST-10 will get you what you're looking for.
If you like Blooming chips, the ST10 is the best for QE. Me, I do not like dealing with the blooms.
Posted 21 May 2013 - 07:09 PM
The KAF3200 (used in the ST10 mentioned by Raginar & blueMan) has 6.8 X 6.8 micron pixels - that would make my sampling about 2.3"/pixel, maybe just a little coarse.
The Sony ICX694ALG (used in the SX mentioned by Iver) is 4.54 X 4.54 and yes, it has impressive QE - this would let me sample at about 1.4" / pixel.
Now to go through the painful process of acquiring one or two of these - always difficult when you are dealing with a manufacturer primarily devoted to consumer products
Posted 22 May 2013 - 02:05 AM
My issues with the Sony chips and these issues may not even affect you:
1) Small FOV - admittedly not too long ago I wasn't overly concerned with having such a small chip, but considering I want to get into widefield photography it is counter intuitive especially with my scope.
2) Small pixels - when compared to the larger pixel CCD offerings, the high QE of the Sony is negated.
If Sony come out with a significantly larger chip and retain that kind of QE, now that would be something to look forward to.
The other thought I have is ... how freaking expensive is it to get a chip straight from a manufacturer that generally sells in bulk quantities to vendors?
Posted 22 May 2013 - 01:03 PM
The last time I checked (2011) Kodak (now TrueSense Imaging) will still sell small quantities). I think the 8300's are about $400.
I am yet to check on the availability of the Sony Imagers.
Posted 25 May 2013 - 09:29 AM
Posted 25 May 2013 - 09:45 AM
I think an 8300 would still be the best bet.
Posted 26 May 2013 - 09:05 AM
Do you recall where you got the pricing info from? I would like to get current pricing on the ICX694ALG for the record,
though I am leaning towards the KAF8300.
Part of the reason for that is the relative ease designing a PCB to support a cooled imager - the KAF's are dual in-line, while the ICX694 has multiple rows of pins. This usually results in a trace routing nightmare http://www.cloudynig...icons/frown.gif
Posted 26 May 2013 - 11:15 AM
i am definitely also interested in this project...
Posted 26 May 2013 - 11:39 AM
I checked to see if I still had one of the emails I normally received to no avail. I was sitting in an electronics lab searching the internet for prices at the time. If they send me another reminder email, I will post back with their contact info. Looking at that design, I'm thinking you'd have to use two pcb's to cover the inner pin outs? Anywho, if you run into a difficulty with pcbs, I can take a design to school and make whatever you'd need. Actually, I want to try and build my own camera one day too.
Posted 28 May 2013 - 09:07 AM
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Posted 28 May 2013 - 12:40 PM
I will check on the availability from Top Source, though I am leaning towards the KAF 8300. IMHO, for a few microns' reduction in pixel size, the increase in complexity may not be worthwhile, at least for the first pass at the design.
The complexity arises in the layout within the cramped confines of the camera head.
There is another reason - To improve cooling efficiency, I was thinking of soldering short, thin wires directly to the CCD from surrounding PCB. This technique is preferable to plugging the CCD into a socket on the PCB. Doing that would be a pain on chips with multiple rows of pins. Most of the thermal loading comes from conduction.
I will still go ahead and find the availability/pricing on the Sony Imager just in case.