... ARC 3.5m | Weather Closure Conditions . The enclosure will be closed by the Observing Specialist under the following conditions. ... This policy will be consulted whenever there are questions or disagreements concerning closure of the APO 3.5-meter telescope due to hazardous conditions or situations, at times when telescope operations are being overseen by an APO Observing Specialist. ... the on-duty Observing Specialist has full responsibility, and sole authority, to make this decision. ...