Oculus handbook Issue 2 January 2013
a mast or roof. As the camera power is taken from the USB cable, any long leads should be as heavy as
possible to reduce the internal resistance. An optimum setup would use a high quality USB extension
cable with AWG 20 power cores, plus a short A to mini B cable at the Oculus end. Active cables can
work OK, but make sure that the cores are AWG 20. The mini B cable is anchored into the back plate
by a ‘Heyco’ clamping bush, but this can be extracted from the plate by compressing the clamp and re-
fitted to your new cable, as necessary.
The Oculus is designed to minimise any lens and dome dewing problems, but these are very common
in optical systems that are cooled by radiation to the sky. It is very likely that you will have dewing on
humid nights unless the dome is kept warm by powering the internal heater via the 12v socket on the
rear of the assembly. This socket can accept a 2.1mm coaxial power plug from any 12v DC supply
capable of driving at least 1 amp - the polarity is not important. Heating will increase the dark signal of
the camera, so be aware that the heater is best used only when necessary. The voltage to the dew heater
can be varied to alter the amount of heat supplied. At 12v input about 10 watts is dissipated, but 6v
input will reduce this to around 2.5 watts when dewing is less of an issue. Don’t exceed 15v, or the
heaters may be damaged.
A rear view of the Oculus, showing the heater socket and USB cable.
