The third camera used in the Starfish competitive camera shootout is a camera that we designated 'CamC'. This camera was designed as an entry level deep sky imaging camera by a European camera manufacturer. It seems like the designer targeted guiding applications with it also, since it does have an integrated ST-4 style guide port interface. The camera has a fairly sensitive Sony image sensor that has extremely low dark current. The camera also digitizes the pixel data with a 16-bit A/D converter and has a very respectable read noise specification.
The image sensor is a bit small compared to the Starfish and CamE thus reducing the FOV over which to find guide stars. Also, the camera only supports the USB 1.1 interface standard and not the current USB 2.0. As such, this camera had the slowest image upload speeds of the cameras tested and by a wide margin. Full-frame upload takes around 3 seconds. This not only makes focusing a bit tedious but will also limit the frequency of guide corrections you will be able to make. The camera does support smaller ROI operation however and this would mitigate this problem somewhat.
The most troublesome problem with this camera's performance relating to guiding, is the fact that the guide pulse durations measured varied wildly. It appears that the guide pulse timing is handled by the controlling computer and thus is directly dependant upon the CPU's workload. Even though we tested with a computer having an Intel Core Duo CPU running at 2 GHz, the pulse width would vary anytime the CPU workload changed. Even moving the mouse around the screen would cause measurable pulse width errors which would affect the accuracy of guide corrections. |