Optical apparatus and control method of optical apparatus

A control method of an optical apparatus that illuminates an object with illumination light,

• the optical apparatus including:
• a first mirror unit that reflects a first portion of generated light including the illumination light from a light-emitting point of the generated light;
• a second mirror unit that reflects a second portion of the generated light;
• an optical element that reflects the generated light;
• a first detection unit that detects the first portion reflected by the first mirror unit;
• a second detection unit that detects the second portion reflected by the second mirror unit;
• an acquiring unit;
• and a determining unit,
• the generated light including the first portion, the second portion, and a main portion, wherein
• the control method of an optical apparatus comprises the steps of:
• illuminating the object with the illumination light including at least a part of the main portion reflected by the optical element;
• causing the acquiring unit to acquire first output information of the first detection unit and second output information of the second detection unit at a plurality of sampling time points;
• and
• causing the determining unit to determine a state of the light-emitting point based on a change in the first output information and a change in the second output information.