The various Philips web-cams have earned a reputation for performing well when used for astronomy work on the back of telescopes. This is due to their good sensitivity (1 lux), small pixel size (5.6um square) and chip size (640 x 480). Their only drawback was the inability to take exposures exceeding 1/7th of a second, limiting their use to planetary, solar and moon imaging.

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All this changed in September 2001 when Steve Chambers,  a member of the Quickcam and Unconventional Imaging Astronomy Group (QCUIAG) announced that he had devised a modification to the camera which would allow exposures of any desired length of time, up to the noise limit of the CCD detector. This exciting new development has opened up the whole skies to the camera and already, stunning results have been seen on various web-sites. The modified camera is known unofficially as the Vesta-SC in his honour.

THE VESTA AND TOUCAM CAMERAS

VESTA 675

Various web-cameras have been marketed by Philips,specifications for all these cameras and their latest drivers can be found at this Philips web-site  . The Vesta 675,680 and 690 use a Sony ICX098AK CCD ; the Toucam 740 and 840 use an ICX098BQ CCD chip.

A more comprehensive list of web-cams and their specifications can be found on my site here together with links to modifications.

Note - Of the Philips cameras only the following - Vesta 645, 675, 680, 690 , 740 and the new 840 (all CCD cameras incorporating the D16510 chip) have been modified for time exposure control by various workers.It is possible that the 750 is the same camera as the 740, with a different accessory. CMOS cameras, in general, are not suitable because of their inferior light-sensitivity.

The images below are all of modifications to the Vesta 680, although the 675 and 690 are identical in the particular part of the circuit to be modified. The Toucam is a one-board device, so the modification is similar, but not identical.

THE MODIFICATIONS

Pix of the camera board and the D16510 chip showing pin 10 lifted, the track cut near pin13 ,the wiring started and fixed with glue.

There are two phases to the modification - one hard, one easy. The first involves separating and lifting one leg of the D16510 IC from the board and soldering four very fine wires to the appropriate points. This is extremely fine work, requiring a very small soldering iron tip and a powerful magnifying glass. The second part requires a small circuit to be built incorporating a 74HC00 IC for switching logic. This is controlled by a small program in the computer, outputting to the board via the parallel port. The long exposure times are thus set from the computer and the results viewed on the screen.

A fully detailed description of this and further modifications can be found on Steve's web-pages here. As the innovator of this brilliant modification, his is the definitive description of the work. Please respect his copyright of this work.

This site has perhaps the best photos of all stages of the modifications.

This site provides a good description of the process and has links to other sites on the subject.

My untidy first attempt looks like this: the IC was mounted in a socket on a piece of perf-board.

but a box covers all ! (this is the MK11 camera)

Already having another camera, I decided to modify that as well, before I forgot the details.

The second go - using the 'dead-bug' IC mounting. View inside the case.The finished camera - the MK111.

Now for some clear skies !