Global shutter vs rolling shutter: understanding the impact on astronomical imaging

In astrophotography, the quality of captured images depends on numerous factors, including the type of shutter used by the camera. The two main types of shutters are the global shutter and the rolling shutter. Understanding their differences is essential for optimizing your astronomical observations.What is a rolling shutter?A rolling shutter captures the image by reading the sensor lines sequentially, usually from top to bottom. This process means that all parts of the image are not recorded at exactly the same time. Thus, if an object moves rapidly or if the camera is in motion, distortions can appear, such as the 'frozen' effect where objects seem tilted or distorted. This phenomenon is particularly noticeable during imaging of rapidly moving celestial bodies, such as planets or the Sun.What is a global shutter?Conversely, a global shutter (global shutter) exposes all pixels of the sensor simultaneously. This means that the entire image is captured at a single instant, eliminating motion-related distortions. This feature is crucial for obtaining accurate images of fast-moving objects, ensuring that their shape and position are faithfully represented.Impact on astronomical imagingIn astrophotography, precision is paramount. Distortions caused by a rolling shutter can compromise the quality of observations, especially when studying transient phenomena or rapidly rotating celestial bodies. For example, during solar imaging, where fine details such as solar flares must be captured accurately, using a camera with a global shutter is advantageous. Similarly, for planetary imaging, where planets rotate on their own axes, a global shutter ensures a faithful representation without motion artifacts.Example of a camera with a global shutterThe mono SC432M camera from SVBONY is equipped with a Sony IMX432 sensor with a global shutter. It offers a high frame rate of 120 FPS and large pixels of 9 μm x 9 μm, ensuring exceptional sensitivity and detailed images. Thanks to fan cooling and HCG noise reduction technology, this camera delivers optimal performance for capturing subtle details of celestial objects. (astronomy-store.com)ConclusionThe choice between a global shutter and a rolling shutter has a significant impact on the quality of your astronomical images. For precise and distortion-free observations of fast-moving objects, a camera with a global shutter, such as the SC432M from SVBONY, is recommended. Understanding these differences will help you make the most of your equipment and improve the quality of your observations.