ASI678MC ZWO Camera

A next-generation uncooled color CMOS camera

• 1/1.8" Sony IMX678 color CMOS sensor with 8.4 million pixels (2 µ)
• Up to 47 fps at full resolution
• 12 bit analog to digital converter
• For planetary images, assisted visuals or “lucky images”

The ZWO ASI678MC camera is equipped with a color CMOS sensor with 8.4 million pixels (3840 x 2160 px) and 8.9 mm diagonal, in 16:9 format. At full resolution, the maximum acquisition speed reaches 47 images/second with a dynamic range of 12 bits. Equipped with the latest technologies of the STARVIS 2 sensor architecture offered by Sony, the camera offers state-of-the-art features: total absence of electroluminescence, wide dynamic range, very high sensitivity in the near infrared, dark current and very low readout noise.

With its 1/1.8" format color sensor, the ZWO ASI678MC camera is suitable for planetary imaging at high acquisition speed. You will thus obtain magnificent photographs of the planets, in color, freeing yourself from the dangers of turbulence thanks to its sensitivity to In low light conditions, the 662MC offers excellent results in assisted visual aids .

The IMX678 has square pixels that measure just 2 µm on a side. With such small pixels, it is very important to calculate the resulting sampling of your settings based on your viewing conditions and vision. If necessary, you will have to adapt the focal length of the instrument or perform binning, so as not to oversample the images.

Sensor performance

Designed by Sony for surveillance and security applications, the IMX678 sensor is based on the STARVIS 2 technical architecture. The latter integrates powerful functions that allow bright and contrasted images, with significant dynamics, even in extremely limited lighting conditions. The most important is the use of an optoelectronic structure called “back-illuminated” (or BSI, Backside Illumination sensor). All sensor electronics are placed below the photosites; The distance that light must travel through the sensor is reduced, as is the blocking of photons by non-photosensitive electronic elements. Sensitivity increases considerably, even in very low light conditions. The sensor is also extremely effective in the near-infrared (NIR), a spectral band prized by planetary astrophotographers for its lower sensitivity to atmospheric turbulence. This staggered structure allows more electronic components to be placed within the sensor itself, such as ADC, thus minimizing artifacts and noise.

Compared to previous generations of Sony sensors, the IMX678 offers very low read noise and reduced dark current, significantly improving the signal-to-noise ratio. When comparing two black images, we see that the ASI178MC image is less noisy and smoother.

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

The reading noise is the sum of several components: the thermal noise of the photosites, the noise linked to the sensor electronics and the quantization noise from the analog/digital conversion stages. The lower this read noise, the better the results; Therefore, technological work is carried out at each level to reduce it as much as possible. At the output, the camera incorporates a HCG (high conversion gain) device that can reduce playback noise at high gain while retaining the large dynamic range that would be obtained at low gain. This HCG mode is automatically activated as soon as the gain reaches 80.

The assembly mechanics

The ASI678MC has an M42 type female inlet thread; back focus is 12.5mm. A mechanical M42 to 31.75mm male converter is supplied, as well as a 2m long USB cable and an ST4 autoguide cable. ZWO also offers a good quality 2.5mm focal length lens. Thus equipped, the camera can also act as an All-Sky camera for sky surveillance.

Software

As with all ZWO brand cameras, the main and most complete camera control software is ASIStudio , downloadable for free from the manufacturer ZWO's website. The brand also offers a free SDK (Software Development Kit) so that many software programs, free or paid, natively support ZWO cameras: Prism, NINA, FireCapture, MaximDL, SharpCap, PHD2, AllSkEye, etc. We invite you to consult the specific documentation of this software for its level of compatibility or visit the ZWO website for a comprehensive list.

ZWO also offers a unified ASCOM driver to control all your accessories through the ASCOM/Alpaca platform. This driver can be downloaded for free from the ZWO website.

For Linux and Mac users, Indi or Indigo drivers They are free and available on the websites of these platforms. Control is then carried out using the KStars/Ekos software (on Linux) and AstroImager/AstroTelescope from the CloudMakers editor (on Mac).

Finally, ZWO cameras can be accessed through video drivers such as DirectShow or TWAIN. For more details, please visit the ZWO website.

Specifications

Characteristic	ZWO ASI678MC Camera
Sensor
Sensor	CMOSSony IMX678
Sensor type	Colors
Sensor format	1/1.8"
die size	3840 x 2160 pixels
Dimensions of a pixel	2.0 x 2.0µm
Die dimensions	7.7 x 4.3mm (diagonal: 8.86mm)
Pixel capacity	11,270 e-
Electronic
A/D converter	12 bit
Gain	2.75 e-/ADU
Reading noise	0.6 to 2.7 e-
Shutter	Electronic, “roller blind” type
Exposure time range	32 µs at 2000
Cooling
Cooling type	Passive
Cooling regulation	No
water cooling	No
Connections
computer interface	SuperSpeed ​​USB 3.0 Type B
Self-guided interface	Yeah. ST4 compatible with RJ12
Additional interfaces	None
Electrical power supply	5V, via USB port

Mechanical characteristics

Characteristic	ZWO ASI678MC Camera
back focus	12.5mm
Mechanical entry	Female thread M42x0.75
protective porthole	D21 anti-IR glass
Dimensions (diameter x height)	62mm x 37.1mm
Weight	126g

Items delivered:

• 1 ZWO ASI678MC color camera
• 1 x 2.5mm CCTV Fisheye Lens
• 1 USB3 cable (2m)
• 1 ST4 autoguiding cable
• 1 M42x0.75 male to 31.75 mm male adapter, with plug