Abstract: A device for remote detection of surface flaws in enclosed cavities that have been treated with a photoluminescent medium. The device has a non-rotating ultraviolet radiation source, an offset rotary drive means, a passive rotary scanning means that includes a plurality of lenses, reflectors and an optical filter, a non-rotating solid-state photodiode, and support electronic circuitry. Ultraviolet radiation from the illumination source is projected onto the test-part surface and causes dye penetrant that has been previously deposited onto the test-part surface to fluoresce at a different wavelength, thus revealing the presence of surface cracks and flaws. The receiving lenses capture the fluorescent light and project it onto the photodiode, which generates a series of electrical pulses that correspond to the presence of surface flaws. By encoding the linear and angular position of the scanning means, an accurate and quantitative map of the flaw pattern can be constructed.