ASI 461 MM Pro Mono Camera

The ASI461MM Pro is a cooled monochrome camera for demanding astrophotographers and for astronomical research.

It uses the Sony IMX461 CMOS chip, measuring 44 x 33 millimeters, with 100 megapixels and a resolution of 11656 × 8750 pixels. Thanks to the Backlit technology makes the sensor especially sensitive.

BSI, backlit CMOS structure:

One of the advantages of the back-illuminated CMOS structure is increased sensitivity. With a classic front-illuminated sensor, photons entering the sensor's light-sensitive layer must first pass through the metallic wiring located directly above it. The wiring structure reflects some of the photons, reducing the sensor's efficiency.

With a backlit sensor, light can penetrate the photosensitive layer from the back. In this case, the wiring embedded in the sensor is located below the photosensitive layer. As a result, more incident photons strike the light-sensitive layer.

The ratio between photons and the electrons generated is called quantum efficiency. The higher the quantum efficiency, the more effectively the sensor converts photons into electrons and the more sensitive it is.

Two-stage cooling: An integrated thermoelectric cooler (TEC) keeps the sensor up to 35°C below ambient temperature. At 0°C, dark current noise is only 0.003 e/s/pixel. This means that a 300-second exposure results in a dark current of only 0.7 electrons. This is below the camera's readout noise! ​​At -20°C, the noise drops below 0.00024 e/s/pixel, so even 5-minute exposures are virtually noise-free.

Anti-fog function: On clear nights, the front glass of the camera gets very cold; the humidity in the air condenses and ruins photos. An ultra-thin polyimide heating element warms the glass just enough to prevent condensation. This "Anti Dew Heater" consumes about 5 watts and can be switched off to save energy.

No amplifier brightness Conventional CMOS sensors are a weak source of infrared light during operation, which is often visible in the corners of uncalibrated images. This is a typical sign of so-called "magnifier glare." With this camera, you don't have to worry about amplifier glare, even with high gain and long exposure times. Amplifier glare suppression technology is already implemented in the firmware. No additional software is required.

Color or black and white? Monochrome cameras have one advantage: they are much more sensitive and have better resolution than color cameras. Color cameras, on the other hand, require a larger investment: they need color filters and a filter wheel.

Summary:

• Cooled camera with large sensor for DeepSky photography
• Sony IMX461 CMOS sensor
• 100 megapixels: resolution 11656 x 8750 pixels
• No amplifier glow (Amp Glow)
• Quantum efficiency of approximately 91%

Specs: