A flip-up helmet mount for a night vision goggle includes a plurality of nested relatively movable brackets, the first of which is secured to a user's helmet. A second bracket pivots relative to the first to provide flip-up motion for the night vision goggle, and a third of the nested brackets is pivotal on the second bracket to provide a tilt angle adjustment for the night vision viewer. In order to both save battery power, and to prevent the user from inadvertently revealing his position by forgetting to turn off the night vision viewer before flipping it up, the support structure includes a magnetic flux source cooperable with a magnetically-responsive switch of the night vision viewer to maintain the viewer turned on only when the viewer is in its use position. When the viewer is flipped toward its upward position, the magnetic flux source is responsive to a combination of gravitational force and centrifugal force to move away from the magnetically-responsive switch device and effect turning off of the viewer. Because the viewer remains mounted on the flip-up mount during this series of events allowing the user an unobstructed natural view of the environment, the viewer is immediately available to be flipped downwardly to its use position to be placed back into operation. The gravitationally-responsive magnetic flux source moves back into association with the magnetically-responsive switch when the viewer is returned to its use position.