Gossen Lunasix 3 Light Meter

Vintage Gossen Lunasix 3 light meter in excellent condition. Made in West Germany sometime in the mid to late 1980s. The meter works but I do not know how to test it properly. The batteries are very low but should be strong enough to test the meter. Details: Gossen Lunasix 3 is a durable, analog exposure meter featuring both incident and reflected light measurement with a sliding dome and a 30° measurement angle. Key specifications: ASA/ISO range of 0.8–25000 Aperture range of f1–f90 Time range of 8 hours to 1/4000s. Key Features Analog Display: A classic, robust design with analog dials for readings. Measurement Modes: incident (light falling on the subject) and reflected (light bouncing off the subject) light measurement. Incident Dome: A sliding incident dome allows for accurate light readings on the subject. Measurement Angle: 30° measurement angle for reflected light readings. Accessory System: The meter features a front aperture for attaching various accessories, such as tele or micro attachments for specialized measurement angles or densitometry. Exposure Compensation: Includes built-in exposure compensation.