Charleston Observatory

Vesta SC - Long Exposure mods

On this page I detail the modifications to a Vesta webcam to convert it into a long exposure capable CCD imager. These modified cameras are then referred to as Vesta-SC, in recognition of the original developer of this modification, Steve Chambers.


Schematic Diagram showing additional circuitry added to the Vesta Webcam. This design is based on the Steve Chambers modification, and works with Peter Katreniak's K3CCDTools software. I did make a slight change, I had a 74HC10 handy so I used that instead of the 74HC00. Schematic below is the result of the part number change. 

Click on the image to view the full schematic


  • A webcam capable of accepting the mods, see list of models below :
  • Mod capable cameras include:

Philips Vesta PCVC675, Vesta PCVC680, Vesta PCVC690, 

Toucam Pro PCVC740, Toucam Pro II PCVC840, Philips SPC890 and SPC900.

Although the information posted here is for the Vesta line of webcams, these mods are applicable to several models of webcam, as listed above. These webcams are currently in short supply, due to Philips getting out of the webcam business. Occasionally I see a short-line source for these cameras but the supply seems quite sporadic. Average prices on these webcams has recently jumped as the demand exceeds the supply.

The older Vesta PCVC and Toucam cameras have drivers for Windows 98-XP
The newer SPC890 and SPC900 have drivers for Windows 7

The Toucam can be Firmware Flashed to allow the Win7 drivers to function.

Other than the webcam itself, you will require...

  • good quality fine-tipped soldering iron
  • circuit board holder
  • very fine solder
  • solder-wick braid
  • a strong hook-like object
  • X-Acto knife
  • Male DB25 connector and cable
  • 74HC10 Integrated Circuit (NAND)
  • (2) 470 ohm resistors
  • (2) 10K ohm resistors
  • (1) 100K resistor
  • toggle switch, SPDT or DPDT
  • very fine (32 awg) wire - insulated


  • Open the camera shell. Remove the two circuit boards and tripod mount.
  • Unplug the CCD Ckt board from the main board.
  • Unplug the USB cable from the main board.
  • Identify the various components on the circuit board.
  • Identify the traces and pins to be cut / lifted
  • Cut the trace at Pin 13 of the NEC D16510
  • Lift Pins 8 and 10 of the same chip
  • Solder fine wires to the following points:
  • -- Via next to cut trace at Pin 13
    -- Via next to NEC D16510 chip that is connected to Pad 10
    -- Pin 10 of NEC D16510 chip
    -- Pin 8 of NEC D16510 chip

    -- Pin 13 of NEC D16510 chip

  • Now build the "Dead Bug" chip circuitry per the schematic. It is referred to as the dead bug mod as the chip lies on it's back with the legs in the air. Stick upside-down to the circuit board with double-sided tape.
  • Mount the Parallel cable (DB25 Male) and the switch in the case.
  • Solder all the new wires and resistors to the new NAND chip, the Parallel Cable and the switch.
  • Test all connections with an ohm-meter to ensure that nothing is shorting or not connected
  • Re-assemble the camera into the shell
  • Mount on a tripod, load K3CCDTools on your PC and try it out!!

(reference some superb step by step photos at Peter Katreniak's site below

This image of M17 - the Swan Nebula - was my first long exposure capture. While I have since moved on to better and more capable dedicated Astro-CCD cameras, this remains one of my favorite images as it was my first.
It is included here for nostalgia... 

M17 imaged with a Long Exposure webcam

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