Dark Nebulas Detection - Integration time and subexposures
Posted: Fri Mar 05, 2021 3:25 pm
Hello everyone,
It is often seen people taking longer subexposures to detect dark structures (eg. M78), tipically at least 5 min. However, reading Dr. Robin Glover detailed explanation in this forum about picking the correct exposure, the best SNR for a given total integration time is achieved with a single subexposure time, which is independent of the object signal, and usually less than 5 min. In addition, the integrated object signal depends on the total integration time, not the subexposure time.
Is the need of longer subexposures to shoot dark structures a myth or is there any theoretical support to it? If the latter, what am I missing?
Cheers,
André
It is often seen people taking longer subexposures to detect dark structures (eg. M78), tipically at least 5 min. However, reading Dr. Robin Glover detailed explanation in this forum about picking the correct exposure, the best SNR for a given total integration time is achieved with a single subexposure time, which is independent of the object signal, and usually less than 5 min. In addition, the integrated object signal depends on the total integration time, not the subexposure time.
Is the need of longer subexposures to shoot dark structures a myth or is there any theoretical support to it? If the latter, what am I missing?
Cheers,
André