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Extreme sensitivity back-illuminated Scientific CMOS camera.  4 megapixel sensor with 6.5 micron pixels, Adaptive Optics capable, StarChaser Guider compatible.

Aluma AC2020BSI features a Windowless Class 1 sensor.

Fused silica chamber window is available with either VIS-NIR or UV-VIS optical coating options.


The SBIG Aluma AC Series represents the state-of-the-art in Advanced Scientific CMOS cameras for astronomical imaging systems. The camera’s advanced design permits high speed download via the USB 3.0 connection to the control computer. The Aluma AC2020BSI uses the Gpixel GSENSE2020BSI-H CMOS sensor with 4 million pixels at 6.5 microns in a 2048 x 2048 array. The sensor measures just over 13.3mm square. The Aluma AC series has powerful two stage cooling and supports optional water cooling. Aluma AC cameras can be operated directly from a 12VDC 8A power supply.

Design features include:

Back-Illuminated Sensor

Incredible sensitivity! High performance back-illuminated sensors are flipped over and thinned during manufacture, so incoming light does not encounter any circuitry before hitting the sensitive pixel area.  This provides optimum sensitivity across the entire visible spectrum – and beyond.

The sensor in the GSENSE2020BSI-H has a peak quantum efficiency of 91%, with a broad peak in the visible spectrum.  For near UV and IR applications, it  features good sensitivity all the way from 200 nm to 1000 nm.


Chamber Window Coating Options

The GSENSE2020BSI-H sensor is windowless, which provides the optimum sensitivity across the sensor.  For windowless sensors we recommend recharging the desiccant plug annually, to avoid any risk of moisture contamination on the sensor.

The fused silica optical window on the sealed sensor chamber is available with two standard coating options, depending on your application.  VIS-NIR provides optimal sensitivity from 400 nm through 1000 nm.  UV-VIS provides optimal transmission from 250 nm through 700 nm.


The Aluma AC2020BSI scientific CMOS camera features StackPro™, a revolutionary feature that performs image stacking inside the camera.

CMOS sensors often have more limited well depth and bit depth than their CCD predecessors.  At the same time, the modern CMOS sensors have much lower read noise than the equivalent CCD.  This low read noise can be used to advantage, by stacking many shorter exposures to achieve the same final result.  This does however result in a lot of extra disk usage and post-processing.

StackPro™ performs the stacking automatically, inside the camera.  It automatically subdivides your exposure into up to 16 individual subexposures, and stacks them inside the camera prior to download.  This eliminates the excessive amounts of data cluttering up your hard drive.  Stacking can also be used as an alternative to High Dynamic Range (HDR) mode.

HDR Mode

The sensor in the AC2020BSI is capable of operating in HDR mode, where high-gain and low-gain images are read out simultaneously.  Our included MaxIm LT software features an HDR merge feature, which greatly simplifies the process of producing clean, highly linear images.

Superior Cooling

Proven pin heatsink design shared with industry leading STX series cameras gets the heat out while providing low vibration.  Includes SmartCooling™ intelligent thermoelectric cooling and fan operation.

Water Circulation Ready

For high ambient temperature environments, the liquid cooling option improves thermal performance and helps minimize dark current.

User Rechargeable Desiccant

SBIG pioneered including a high-tech user-replaceable cartridge with ceramic filter and molecular sieve desiccant. Unlike competing cameras, which require factory service when their chamber desiccant eventually saturates out, the user can easily recharge the desiccant.  This eliminates the need for costly service – not to mention the associated down-time and shipping costs.  This feature is especially important in high-humidity locations.

Electronic and Mechanical Shutters

The GSENSE CMOS sensor has an electronic rolling shutter.  In addition the Aluma AC series cameras include a mechanical shutter to enable convenient dark-frame subtraction for optimal performance and sensitivity.  This is essential for remote/robotic operation.


Optional 12 Position Filter Wheel

The Aluma AC2020BSI is compatible with the new 12 position SBIG AFW-12-50R filter wheel, utilizing 50 mm round filters.

It is also compatible with the 7 position FW7-STX filter wheel, utilizing 50 mm square filters.

Self-Guiding and Adaptive Optics Options Available

The available SBIG StarChaser SC-3 is an excellent low-cost option for integrated autoguiding in front of the filters, and it supports our SBIG AO-X Adaptive Optics accessory.

The AO-X uses a tip-tilt window to quickly and precisely adjust the image position in response to autoguider feedback.  With Adaptive Optics there is no backlash, stiction, or lag, and the movements are precise and accurate.  This allows the AO-X to not only remove the effects of periodic error, drift, and wind gusts, but also reduce the effects of atmospheric seeing.  When used with an Aluma AC camera, the AO-X requires the StarChaser SC-3.

For more information please see AO-X.

USB 3.0 Interface

The Aluma AC includes a USB 3.0 interface port for high speed downloads.  For installations where longer cable lengths are required, the port is also compatible with USB 2.0.

I2C AUX Port

The STX cameras have a convenient auxiliary control port (also known as an I2C AUX port), which controls the filter wheel and provides optional external trigger interfaces.  Unlike older SBIG models, the AUX port is not used for AO-X control, as this function is now handled by the optional SBIG StarChaser SC-3 off-axis guiding camera.

MaxIm LT Software

All SBIG cameras come with our MaxIm LT software – a $249 value! MaxIm LT is a special version of our venerable MaxIm DL software that provides complete control of your camera, filter wheel, and autoguider, plus advanced image processing capabilities. If you wish you can upgrade to MaxIm DL Pro to get complete observatory integration and even more processing and analysis capabilities.

Included Accessories

All Aluma AC cameras include a deluxe carrying case, universal power supply, Aluma AC power extension cable, USB 3.0 cable, and MaxIm LT software.




SBIG Aluma AC2020BSI

Sales Tax Included
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