An illuminator includes: a body with an opening, for receiving optical means; illuminating means arranged around the opening in a frontal face of this body and commandable to illuminate a space in front of the frontal face, electronic control means of the illuminator; heat dissipating means; connecting means for removably fixing the illuminator at least to the optical apparatus. The body of the illuminator includes a rear face opposite the frontal face which includes a plurality of distinct functional case elements positioned around the opening for receiving at least the electronic control means and/or which defines the heat dissipating means and/or the connecting means, in such a manner as to enable an operator, when the optical apparatus is associated with the illuminator, to access the optical means to dismantle the optical means from the apparatus and/or adjust optical adjusting means of the optical means.