This photographic technique involves setting a camera’s shutter speed to remain open for an extended period, typically ranging from several seconds to multiple hours, while aimed at the night sky. The extended exposure allows the camera sensor to capture faint light from celestial objects, such as stars, nebulae, and galaxies, which would otherwise be invisible in shorter exposures. A common result is the capture of star trails, caused by the Earth’s rotation during the exposure.
Employing extended durations for capturing astronomical subjects offers several advantages. It allows imaging of faint objects, revealing details not visible to the naked eye or in standard photographs. Furthermore, it makes possible the creation of visually stunning images that convey the vastness and beauty of the universe. Historically, this methodology has enabled groundbreaking astronomical discoveries and continues to be a valuable tool for both professional astronomers and amateur astrophotographers.