ZWO ASI533MM-Pro
The ASI533MM Pro camera is the mono-version of the very successful ASI533MC Pro. It houses a 9 Megapixel square backside illuminated sensor with dual-gain technology. It essentially has no dark current, does not suffer from amp-glow and generally produces very clean images. The pixel-size of 3.76 is the same as many other cameras currently on the market.
Being a Pro-version it has cooling built in. The sensor can be cooled down to about 35 ºC below temperature, slightly less powerful than the ASI1600. The camera can use 1.25” mounted filters.
The connections are the same as other ZWO cameras, with a USB-3 connection for image download and a dual USB-2 hub. The camera requires 12V DC power at all times. Previous models could connect with USB-3 only and used the power for cooling. The ASI533MM needs power connected for the USB connection to be established.
The ASI533MM has been acting as the successor of the ASI1600MM at the observatory, very suitable for small to mid-size targets.
Specifications
Sensor: Sony IMX533CLK-D
Resolution: 3008 × 3008 pixels (9Megapixels)
Sensor-size: 11.3 x 11.3mm; 15.97mm diagonal
Quantum Efficiency: 91%
Full well capacity: 50ke
ADC: 14-bit
Interface: USB3 (image download) and 2 x USB2 hub
Camera size: 78mm diameter, weight 470g
Connections
The connection layout on most of the cooled ZWO cameras is very similar. The main connection is a USB3 port. This allows for very fast download speeds of images into the acquisition computer. Unfortunately it still uses the clunky B-type plug. A USB-C connection would be more convenient. The choice for B-type does eliminate the risk to mistakenly use one of the other two type-A plugs, which are USB2. These connectors are actually a small USB-hub. Typical devices that connect through this hub are the filterwheel and (if used) a guide-camera.
Next to the USB-ports is the 12V DC connector. This separate power supply is needed at all times and if cooling is on, can draw quite a bit of power.
Square Sensor
The sensor in the ASI533MM Pro has a square format. For galaxies, clusters etc, this makes for easy composition. But it might not be to everyones taste. The 11.31 mm length/width and 9 Megapixel is not very large. Many deep sky objects fit very well in the frame when combined with the 1000mm TOA-130 telescope. But for larger nebulae the ASI6200MM Pro is a better fit. The sensor has dual gain and essentially no dark current and/or amp glow and a very low noise-level. Pixel-size is 3.76 µm, similar to many other astrocamera’s. With the 1000mm TOA-130 telescope the pixel-scale is 0.78 arcsec/px and for the FSQ-106 it is 1.48 arcsec/px.
EOS-EF mount
With the flattener on the telescope, the back focus distance from the flattener to the sensor-plane is critical. Finding the proper adapters can be a tedious job, and many people have custom adapters made for their equipment. Historically I made a lot of use of the EOS-EF mount. ZWO makes EF adapters for all cameras with 44mm backspace. Takahashi designs imaging trains for EF mounts for all telescopes. And the bajonet connection makes mounting very easy. As cameras got bigger and heavier, most connections at the observatory are now standardized to M68, and the EF format is rarely used.