New C2-9000 Camera with IMX533 CMOS sensor

Main page▹Product Overview▹Astronomical cameras▹News	26.5.2023 \|

The C2-9000 is a perfect starter camera for any serious beginner, regardless if he or she aims to capture beautiful images of deep-sky objects or to acquire serious data for astronomical research. With the sensor size approximately 11 × 11 millimeters, C2-9000 does not demand latest correctors and flatteners, it perfectly works even with common optics. But C2-9000 is not for beginners only, it grows with the user and its high sensitivity, exceptional dynamic range, low read noise and dark current are appreciated also by the most advanced astro-imagers as well as researchers demanding the best possible data. Compact yet robust, time-proven body of the C2 camera allows for all-containing device with mechanical shutter and internal filter wheel, very efficient and regulated sensor cooling and extremely fast USB3 connection. Options do not end here — C2-9000 can integrate with external filter wheels with up to 12 filer positions, OAG adapters, Nikon and Canon bayonets and numerous other telescope interface standards.

C2 camera with rolling shutter sensor

All current C2 cameras employ Sony IMX sensor with global shutter. The C2-9000 is the first C2 camera with back illuminated Sony IMX533 CMOS sensor with rolling shutter and 3.76 × 3.76 μm pixels.

Model CMOS sensor Resolution Pixel size Image area

C2-9000 IMX533 3008 × 3008 pixels 3.76 × 3.76 μm 11.31 × 11.31 mm

Remark:

The sensor belongs to the same family like sensors used in the C1×, C3 and C5 camera lines, only the digitization precision is 14-bit instead of 16-bit of the larger sensors.

C2-9000 camera head with internal filter wheel

The IMX533 sensor used in C2-9000 camera shows very good linearity in response to light. This means the camera can be used for advanced research projects, like the photometry of variable stars and transiting exoplanets etc.

Response of the Sony IMX rolling-shutter sensor (IMX533)

Controlling of the rolling shutter sensors differs significantly from controlling of the global shutter sensors and thus the camera C2-9000 internals are quite different from other C2 models.

The C2-9000 contains 256 MB of onboard memory, capable to store up to 14 full-resolution frames. Camera API allows for sequential exposures, during which short-exposure images are stored into memory possibly faster than the host computer is able to read them. Sequential exposures are paused when the internal memory is filled with images, not yet read by the host PC. As explained earlier, rolling shutter sensors are capable to perform image exposure while digitizing the previous image.

C2-9000 camera without filter wheel (left), with internal filter wheel (center) and with external filter wheel (right)

Thanks to C2-9000 onboard RAM, downloading of the image to the host computer does not influence image digitization process, as the download only transfers already digitized images from camera memory.

Time needed to digitize and download single full frame depends on USB connection type.

Full-frame, USB 3.0 (5 Gbps): 0.06 s
Full-frame, USB 2.0 (480 Mbps): 0.40 s

Generally, many sensor characteristics depend on the used gain.

Gain number Gain in dB Gain multiply Conversion factor Read noise RMS Full well capacity

0 0.0 dB 1× 3.05 e-/ADU 3.90 e- 50,000 e-

4030 36.0 dB 63× 0.06 e-/ADU 2.76 e- 950 e-

Remark:

Please note the values stated above are not published by sensor manufacturer, but determined from acquired images using the SIPS software package. Results may slightly vary depending on the test run, on the particular sensor and other factors (e.g. sensor temperature, sensor illumination conditions etc.), but also on the software used to determine these values, as the method is based on statistical analysis of sensor response to light.

The camera driver and user’s applications offer wide variety of binning modes up to 4 × 4 pixels as well as all combinations of asymmetrical binning modes 1 × 2, 1 × 3, 1 × 4, 2 × 4 etc. To allow such flexibility, binning is performed only in the camera driver (software binning) and does not rely on the limited capabilities of the hardware binning.

The negative side of software binning is the same download time like in the case of full-resolution 1 × 1 mode. This is why the C2-9000 camera also implements 2 × 2 binning mode in camera hardware.

The shortest theoretical exposure time of the C2-9000 camera is 49 μs. However, such short exposures have no practical application, especially in astronomy. The camera firmware rounds exposure time to a multiply of 100 μs intervals, so in reality the shortest exposure time is also 100 μs.

Remark:

Note the individual lines are not exposed at the same time, regardless of how short the exposure is, because of the rolling-shutter nature of the used sensors. The difference between the first and last line exposure start time is 37 ms.

There is no theoretical limit on maximal exposure length, but in reality, the longest exposures are limited by saturation of the sensor either by incoming light or by dark current.

C2-9000 camera variant interfaces

Other C2-9000 camera features like cooling efficiency, 12 V DC power and USB3 connection, telescope interfaces etc. are the same like the other C2 camera lines. Refer to the C2 camera product page for more details.

C2-9000 first light

Object M51 “Whirlpool Galaxy”

Author Martin Myslivec

Camera C2-9000

Filters LRGB

Exposure 10 hours (2.5 hour per LRGB channel)

Telescope 400 mm f/2.9 astrograph