Why do I need to cool my camera?
Steve says: “The sensor in a digital camera warms up during the long exposures required for deep-sky astrophotography.
This energy produces what is known as ‘thermal noise’, as the heat tricks the sensor into believing that it has received some additional photons.
These false detections result in fully saturated pixels being peppered across the image.
Modern astro cameras designed for deep-sky imaging are equipped with Peltier cooling systems that are attached to the rear of the sensor to reduce the temperature by between 25° and 50°C below the ambient temperature, thus dramatically reducing the unwanted noise.”
Email your astronomy queries to Steve at email@example.com and they could get answered in a future issue of BBC Sky at Night Magazine.