Physical dimensions of the Sony ICX445 CCD detector, used in G1-1200 cameras, correspond to G1-0300 or G1-0800 cameras. But G1-1200 has 1.2 millions pixels measuring only 3.75 × 3.75 μm. The EXview HAD CCD production technology, ensuring high quantum efficiency especially in near infra-red portion of the spectrum, is particularly important for usage in astronomy when capturing dim stars or other objects.

Despite relatively small physical dimension of the CCD chip itself, the package is too large to be used in the round head of G0 cameras. So the 1200 model is available only in somewhat larger head of G1 cameras (similarly to G1-1400 model).

G1-1200 cameras are offered in monochrome as well as color variants:

Image digitization speed can be chosen between 2.5 MPx/s and 8 MPx/s. The whole image can be downloaded in a fraction of second, which is particularly important for automatic guider. Analog/Digital converter resolution is 16 bits (65,536 levels), which is even more than the dynamic range of the used CCD detector.

The CCD detector is equipped with electronic shutter, which allows capturing of very short exposures (shortest exposure is 125 μs). Longest exposure is on the other side limited only by the detector saturation, which allows automatic guiding using much dimmer stars compared to the best web or TV cameras. When coupled with a guiding telescope with focal length around 30 cm and diameter around 8 cm, G1-1200 can detect guiding star after several seconds of exposure time almost anywhere on the night sky.

As well as other G0/G1 cameras also the G1-1200 is equipped with standard “autoguider” port. This port allows direct connection of camera and telescope mount compatible with this standard, introduced by SBIG. The G1-1200 camera has mount switching circuits isolated from the rest of the system (camera itself, USB and host computer), which enhances reliability and noise resistance. Maximum switching current is 150 mA and on state resistance around 10 Ω.

The guiding itself is performed by the SIPS (Scientific Image Processing System) software or by other camera control software, for which G0/G1 camera driver exists (e.g. MaxIm DL or AstroArt) or which is capable to use general ASCOM camera drivers. Automatic guiding running in SIPS utilizes the computational power of modern PCs to achieve sub-pixel precision of star position, so it can guide very precisely even if a guiding telescope with short focal length is used.

SIPS software performs not only guiding, but also allows automatic calibration independently on camera orientation, recalculates calibration parameters when the telescope is moved to different declination so no calibration is needed. The guide star can be kept on defined pixel coordinates, which allows placing of the guide star on the same position during subsequent observations etc. Differences from reference positions are displayed graphically and all guiding actions including measured differences and performed corrections are logged into text window and can be saved into text file.