Cooled Greyscale Quickcam (continued)
I modified the imager in order to reduce the lead length from the CCD to the circuit board from 2.75 inches to 2.0 inches. This involved moving the project case towards the front about an inch and placing the circuit board on the very bottom of the project case. This was done to avoid suspected damage to CCD chip from leads that are too long. I made a switch to select 12 volts from a marine battery or 7.2 volts from a 2000mAH model racing car battery. Here's a pic of the switch:
The switch was my attempt at better control of the peltier's cooling instead of operating it at 12 volts only. I found that the CCD runs cooler at 7.2 volts. On the first night of operation the ambient temperature was 33 degrees F. At 12 volts the CCD temperature was 12 degrees F; at 7.2 volts the temperature was 3 degrees F. A Radio Shack digital thermometer is used to monitor the CCD's temperature. The thermometer sensor is mounted on the cold plate just below the CCD.
First light on the scope (10" LX200 f/3.3) was on 2/15/00 with much Moonlight and cloudy skies. I was able to eek out these images with heavy processing:
Trapezium (Anti-blooming turned off) - Stack of 12 short exposures
On the right is a screen dump of a raw image of M51 and the settings used in QCV2. 13 exposures of 90 seconds each were stacked after subtracting one dark frame for the resulting image on left.
UPDATE: Click here for peltier control by adjustable power supply
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