The present disclosure provides an optical system suitable for detecting muzzle flashes in a scene, the optical system comprising: a first optical module customized for detecting flashes at short range of the optical system by analyzing irradiance received on a first infrared sensor; a second optical module customized for detecting flashes at long range of the optical system by analyzing irradiance received on a second infrared sensor; wherein: the first and second optical modules are configured to share a common field of view and to operate independently of each other.