My version of the Cookbook Camera Head has some obvious changes and some not so obvious changes from the original version described in the manual. The first thing, I choose not to use the supplied metal housing from University Optics. The original pre-amp housing also does not provide enough support as I wanted to use a connector and cable between the camera head and the control unit. So I purchased a "bud" box with just the right inside dimension to hold the pre-amp board. The box is mounted to the camera body with 2 threaded 1/4 inch hex standoffs with are also one of the 3 screws which hold on the front and rear body cover plates. This method also provides a much better solid ground connection for the pre-amp with the camera body. You will notice that there is an adjustment pot on top of the box. This is a 10 turn pot with a value of 500 ohms and is put in series with P1 on the pre-amp board. P1 is normally a 1000 ohm trimpot, but I changed mine to a 500 ohm trimpot. The sum of the 2 pots now has a range of 1000 ohms, just as in the original circuit design. But with the 10 turn pot on top of the box I get a MUCH finer adjustment of the Reset voltage. And I don't have to fumble around trying to adjust trimpot P1 in the dark.
The DB-25 signal connector is mounted on the back of the "bud" box to provide a connection to the Control Unit. All of the low level signals, temperature sensing, and Peltier voltage go into and out of this connector. Having this connector for the camera head allows me to remove it from the Control Unit for easy storage in the Control Unit carrying case. This cable is approximatly 15 feet in length which allows me to get a reasonable distance from the telescope and the computer table. That way I'm not right on top of the telescope.
The water lines used in the original design are normally 1/8 inch inside diameter plastic hose. On mine I decided to use 1/4 inch inside diameter plastic hose so I could increase the amount of water flow for better temperature stability. This effectivly increases the size of the heatsink on the camera body which slows down temperature drift. These lines are coupled to a submersable water pump which runs at 110 VAC. It is the type used for water fountains and pumps about 200 gallons per hour. Using 1/8 inch line would have severly impacted the water flow from the pump. I normally use a 5 gallon bucket of water with ice to bring the water temperature down. The pump is also placed inside a small 1 gallon bucket so the heat from it does not contribute to the main water supply. I routinly get a Cold Finger temperature of -35 degrees centigrade with this combination.
The inside of the camera body is lined with anti-static foam to reduce the thermal effects of the body side walls with relation to the Cold Finger, which is where the CCD chip is mounted. Mounted and epoxied inside a small hole on the Cold Finger is the LM-35 centigrade temperature sensor. The output from this sensor reads directly in Centigrade from -40 deg C to + 100 Deg C. The output is read on a digital panel meter on the Control Unit and is also used to control the proportional temperature controller for the Peltier.
I also went to great pains to center the TC-245 CCD chip in the center of the optical window. Now my images are dead center to my optical images and this helps a great deal in aiming the telescope. Especially when you consider that at F/4 on a 10 inch telescope the Field of View for this camera is about 21.9 arc minutes x 16.1 arc minutes. There is not a lot of room for error in searching for deep sky objects.
The photo of the Camera Head was taken with a Casio QV100 digital camera.