MORAVIAN C5 100MC [COLOUR]

The Moravian C5 100MC Colour is a high performance cooled colour astronomy camera using the Sony IMX461 medium format CMOS sensor with a resolution of 11664 x 8450 pixels at 3.76μm. The sensor has a large area of 43.86 x 32.90mm, making it the ideal match for professional telescopes with large image circles such as those from Planewave Instruments.

Both C5A and C5S cameras are equipped with Sony IMX rolling shutter back-illuminated CMOS detectors with 3.76 × 3.76 μm square pixels. Despite the relatively small pixel size, the full-well capacity over 50 ke- rivals the full-well capacity of competing CMOS sensors with much larger pixels and even exceeds the full-well capacity of CCD sensors with comparable pixel size.

The used Sony sensors are equipped with 16-bit ADCs (Analog to Digital Converters). 16-bit digitization ensures enough resolution to completely cover the sensor exceptional dynamic range.

Two different body types are available - Asymmetric labelled C5A and Symmetric labelled C5S.

The Asymmetrical C5A variant mirrors the C3 and C4 series in both outer shape and internal construction. The front cross-section of the C5A cameras is the same as the C3 and C4 series, although the used sensors are much larger. The C5's head thickness corresponds to the thickness of the Enhanced Cooling versions of the earlier models.

Asymmetrical models also employ mechanical shutter, allowing you to capture dark or bias frames without the necessity to cover the telescope aperture.

The Symmetrical C5S variant's main purpose is to not exceed the central obstruction of reflecting telescopes with the camera located at prime focus. The asymmetrical variant typically overhangs the central obstruction of smaller telescopes (with ~0.4 m primary mirror diameter), despite the central obstruction of wide-field telescope being rather big.

Due to mechanical constrains, the symmetrical model lacks the mechanical shutter.

Compared to C3 and C4 cameras, both C5A and C5S series feature completely redesigned air cooling - more powerful and also quieter than even the EC variants of the C3 and C4. Also, the supplied AC/DC brick power adapter is more powerful and employs a more robust power plug.

Usage of large sensors required completely new design of the telescope interface, and the C5 series offers M68 × 1 threaded adapter on on the smaller 100 MPx C5 variant. The large 150 MPx version of the C5 offers M85 × 1 threads on the tiltable adapter. Like the C4 series, the internal filter wheel is not an option, so external filter wheels are necessary. The C5 cameras are equipped to control new EFW-5XL series of filter wheels.

Note: Huge sensors require huge 65 × 65 mm square filters and EFW-5XL-5 is designed for five such filters. The EFW-5XL-7 filter wheels for seven smaller 50 × 50 mm square filters are available for 100 MPx C5 variant with smaller sensor. In addition, the SFW standalone filter wheel is available with either 8 + Clear positions for 65mm square filters, or 12 + Clear positions for 50mm square filters (only for the 100M).

The mechanical shutter in the C5 cameras is designed to be as reliable as possible, so the number of open/close cycles is virtually unlimited, because there are no surfaces rubbing against each other. The price for high reliability is slow shutter motion. Luckily, mechanical shuttering is not necessary for exposure control, only for taking dark frames and possibly bias frames — all used CMOS sensors are equipped with electronic shuttering.

Sensors used in C5 cameras offer programmable gain from 0 to 36 dB, which translates to the output signal multiplication from 1x to 63x. The cross point is set to gain 3x (approx. 10 dB), where the full well capacity drops from more than 50 ke- to ~17 ke-. The read noise then drops from ~3.2 e- RMS to ~1.5 e- RMS.

Sensor linearity of Sony IMX461 sensor as found in the C5 100M camera.

The CMOS sensors found in these cameras have a response to light that is linear very close to the saturation point. This means the C5 series cameras can be used for advanced research and scientific applications like variable star photometry and exoplanet transits.

The regulated thermoelectric cooler is capable of cooling the CMOS sensor up to approximately 45°C below ambient temperature. The sensor temperature is regulated with ±0.1 °C precision. High temperature reduction and precision regulation ensure very low dark current for long exposures and allow proper image calibration. 

The USB 3.0 port operates at 5 Gbps allowing for fast transfer rates. C5 cameras are equipped with onboard RAM, capable of holding several full-resolution frames. 

For more information on Moravian C5 cameras, please refer to the Moravian website.

Specifications

Mechanical diagram showing C5A camera with no adapter (top), M68 x 1 adapter (middle) and M85 x 1 adapter (bottom). Detailed diagrams can be found on the Moravian website.

Gallery

Omega Centauri by Mark McComiskey using Moravian C5A-100M and ASA 600.

NGC4753 by Mark McComiskey using Moravian C5A-100M and ASA 600.