ZWO ASI2600MC DUO Astrophotography Camera
The ZWO ASI2600MC Duo camera is a 2-in-1 camera, which combines 2 sensors in the same camera, one for imaging and the other for autoguiding.

The main imaging sensor is a 26 million pixel (6248 x 4176 px) APS-C format color CMOS. At full resolution, the maximum acquisition speed reaches 15 frames/second with 16-bit dynamic range. Equipped with the latest technologies of the STARVIS sensor architecture offered by Sony, the camera offers next-generation features: a complete absence of electroluminescence, high-capacity pixels, wide dynamic range and very low read noise.

The autoguiding sensor is located parallel to the imaging sensor. This is the same SmartSens SC2210 monochrome sensor found in the ASI220MM MINI guide camera.

Important Note: All ZWO ASI cameras equipped with thermoelectric cooling must be powered by a dedicated DC power supply; the 5V power supply from the USB port is not enough. We recommend that you use either a 220V/12V power supply delivering at least 3A, or a lithium battery power supply delivering a voltage between 11V and 15V. The power connector is of the 5.5x2.1 mm type, with the positive pole in the center. Using devices with voltages outside the 11V-15V voltage range can cause serious and permanent damage to the cameras.

A 2-in-1 camera
The ZWO ASI2600MC Duo model contains 2 sensors. The main sensor is the imaging sensor. The secondary sensor is the autoguiding sensor. It is placed next to the main sensor and recovers a small part of the instrument's peripheral field. Although off-center, and sometimes distorted by the instrument's optical aberrations, the image obtained is sufficient to detect a guiding star; current CMOS sensors are very sensitive and can capture stars of significant magnitude in 1 or 2 seconds of exposure.

The integration of the two functions in the same camera reduces connectivity (a single USB cable) and increases speed. Optical splitter and guide camera become unnecessary.

Sensor performance
Designed by Sony for leisure applications, the IMX571 sensor is built on the STARVIS technical architecture. The latter incorporates powerful functionalities allowing the obtaining of bright and contrasted images, with a significant dynamic range, including in low lighting conditions. The most important is the use of an opto-electronic structure called "back-illuminated" (or BSI, Backside Illumination sensor). All the sensor electronics are placed under the photosites; the distance to be crossed by the light in the sensor is reduced, as well as the blocking of the photons by the non-photosensitive electronic elements. The sensitivity is greatly increased, even in very low light conditions. This stepped structure allows more electronics to be placed in the sensor itself, such as ADCs, thus minimizing artifacts and noise.

The Sony IMX571 sensor has 26 million pixels of 3.76 µm side. Its dimensions are roughly equal to those of the APS-C sensor of a Canon R10 or 850D camera. Mounted on short focal astrographs, it will cover a field of several degrees on the sky.

The guiding sensor used in the ZWO ASI2600MC Duo camera is that of the ASI220MM Mini. This is a 1920 x 1080 px SC2210 monochrome CMOS offered by the Chinese manufacturer SmartSens. The sensitivity is very high and the quantum efficiency reaches 92% at 500 nm wavelength, with a read noise of 0.6 e-. The guiding sensor does not benefit from the cooling of the camera.

Quantum efficiency and readout noise are the two most important parameters for measuring camera performance. High quantum efficiency and low readout noise are prerequisites for significantly improving the signal-to-noise ratio.

The read noise is the sum of several components: the thermal noise of the photosites, the noise linked to the electronics of the sensor and the quantization noise from the analog/digital conversion stages. The lower the read noise, the better the results; technological work is therefore carried out at each level in order to reduce it as much as possible. At the output, the camera incorporates an HCG (High Conversion Gain) device that can reduce readout noise at high gain while maintaining the high dynamic range you would get at low gain. This HCG mode activates automatically as soon as the gain reaches 100.

Traditional, older generation CMOS sensors show a very weak specific signal in the near infrared: electroluminescence. It is characterized by uneven illumination at the edge of the field on long exposures which can pose a problem for pre-processing. Due to its different electronic architecture, the ASI2600MC Duo camera does not cause any electroluminescence. So you won't have to worry about it when working at high gain and long exposures.

Electronics and cooling
The combination of USB 3.0 with a 512 MB DDR3 memory buffer ensures stable and secure data transfer, eliminating any risk of saturation / drop in speed or untimely disconnection with the computer during bulb exposures.

The ZWO ASI2600MC Duo camera is equipped with 2-stage Peltier thermoelectric cooling, with fan forced convection. It lowers the temperature of the imaging sensor to -35°C relative to the ambient air, so as to greatly reduce the dark current and electronic noise during long exposures.

* Temperature differential of -35°C was tested in 30°C ambient air. It may decrease when the cooling system operates for a long time or when the ambient temperature drops.

A polyimide heating resistor is installed on the front face of the camera, at the level of the protective glass. It prevents mist or frost from depositing on the glass during exposures

The assembly mechanics
The ASI2600MC Duo has an M54x0.75 female type inlet thread; the backfocus is 17.5mm. Two M54 rings are supplied. They make it possible to compensate for the thickness of a filter wheel (21 mm) and an optical splitter (16.5 mm) to achieve the 55 mm backfocus necessary behind the photo adapters of the optical tubes. An M54 to M48 conversion ring is supplied, so that the camera can be screwed onto a photo adapter with M48 thread.

Optional adapters exist for mounting Nikon and Canon photo lenses on the front of the ZWO ASI2600MC Duo camera.