Moravian instruments, Inc., source: https://www.gxccd.com/art?id=762&lang=409, printed: 30.04.2025 14:09:42

Main page▹Product Overview▹Astronomical cameras

4.4.2025
New CG series of auto-guiding and planetary cameras
 The C0 and C1 cameras proved to be reliable auto-guididers, but sometimes the C0 or C1 cannot be used on OAG because of its shape — both C0 and C1 exceed the front plane, defined by the OAG front thread, and thus they can possibly interfere with the telescope's rear mounting interface. The new CG cameras are designed not to exceed the OAG in the front. But otherwise the CG cameras are essentially the C0 ones in the flat casing.

The new CG series of auto-guiding and planetary cameras are only the reshaped C0 series:

  • The camera body is flat not to exceed the side cross-section of OAG.

  • Autoguider and USB ports are located on the camera back instead of on the camera head side.

The new CG camers (left), compared to the C0 model (right)

CG camera models are equipped with Sony IMX global shutter CMOS detectors with 3.45 × 3.45 μm square pixels. Individual models differ in resolution and dynamic range.

Model CMOS sensor Resolution Digitization Pixel size Image area
CG-1500 IMX273 1456 × 1088 pixels 8-bit, 12-bit 3.45 × 3.45 μm 5.02 × 3.75 mm
CG-3000 IMX252 2064 × 1544 pixels 8-bit, 12-bit 3.45 × 3.45 μm 7.12 × 5.33 mm
CG-3000A IMX265 2064 × 1544 pixels 12-bit 3.45 × 3.45 μm 7.12 × 5.33 mm
CG-5000 IMX250 2464 × 2056 pixels 28-bit, 12-bit 3.45 × 3.45 μm 8.50 × 7.09 mm
CG-5000A IMX264 2464 × 2056 pixels 12-bit 3.45 × 3.45 μm 8.50 × 7.09 mm

C2 camera with XS-sized filter wheel, C2-OAG, and CG auto-guider

C5 camera with XL-sized filter wheel, C5-OAG, and CG auto-guider

CG cameras were designed especially with automatic mount guiding on mind. They work in connection with a host computer (PC). Guiding corrections are not calculated in the camera itself, it only sends acquired images to the PC. The software running on the PC calculates the difference from required state and sends appropriate corrections to the telescope mount. The plus side of using a host PC CPU to process images is the fact, that current PCs provide overwhelming computational power compared to any embedded processor inside the guiding camera. Guiding algorithms then can determine star position with sub-pixel precision, can match all stars detected within the field of view to calculate average difference, which limits the effects of seeing, etc.

Calculated corrections can be sent back to mount using PC-to-mount link. If the mount controller does not support so-called “Pulse Guide” commands, it is possible to use the “Autoguider” port. It is enough to connect the CG camera and the mount using standard 6-wire cable and guide the mount through the camera.

Standard 6-pin Autoguider Port is located beside the USB3 port on the back side of the CG cameras

Standard 6-pin Autoguider Port is located beside the USB3 port on the back side of the CG cameras

The Autoguider port follows the de-facto standard introduced by SBIG ST-4 autoguider. The pins have the following functions:

1 R.A. + (Right)
2 Dec + (Up)
3 Dec – (Down)
4 R.A. – (Left)
5 Common (Ground)
6 Not connected