Abstract: An improved system and method for obtaining photogrammetric measurements which eliminates optical distortions created by thermal gradients on windows that are used to protect the photogrammetry camera. A gate valve is introduced between the window and the wall that opens for a limited time to allow the camera to take measurements of a test article contained within a thermal testing chamber. This limits or eliminates any thermal gradients on the window and improves photogrammetric measurements. With a gate valve the window can be removed entirely, as the gate valve can prevent a thermal gradient from being introduced to the lens of the photogrammetry camera. The improved system is suited for making close-in photogrammetric measures of test articles on earth.