Observatory Policies for Dome Closing Conditions

The Observing Associates have primary responsibility at night for safety on Kitt Peak. The OAs will require the KPNO domes to be closed whenever, in their judgment , such action is necessary to protect telescopes and instruments or to guarantee the safety of the observers.

The OAs have been instructed to close the domes under the following conditions:

• Wind speed: The average wind speed exceeds 45 mph. Individual telescopes might be more restrictive: 40 mph for the Coudé Feed.
• Wind gusts: Extreme gusts of wind speed are occuring.
• Humidity: The ambient air temperature is less than 2.5°F (1.4°C) above the dew-point.
• Temperature: The ambient air temperature falls below -10°C.
• Water: Water is dripping from domes or is condensing on the metal surfaces inside the domes.
• Fog: Whenever fog is present anywhere on the mountain.
• Clouds: When clouds with the potential of dropping precipitation are in the vicinity of the observatory.
• Rain: It is raining anywhere on the mountain.
• Snow: It is snowing anywhere on the mountain or there is snow or ice on the domes which may blow or fall inside the dome.
• Dust/Smoke: Large amounts of dust or smoke are evident in the air.
• Dangerous Conditions: If the OA determines there are dangerous conditions of any kind.

Other circumstances may warrant closing – the OAs have sole authority to make the necessary decision to close.

We appreciate that closing the domes when the sky is otherwise clear can have a significant impact upon your research program. The decision to close is a difficult one and is never made arbitrarily. The OAs are familiar with conditions on the mountain and are in the best position to make the necessary decision. We have tried to make the decision-making process as quantitative as possible (e.g., installation of dew-point measuring machines), but in some cases it is still a judgment call. If you have specific suggestions about how we could improve these procedures, please let me know.

      Dr. Lori Allen                           EMAIL: lallen@noao.edu
      National Optical Astronomy Observatory
      Director, Kitt Peak National Observatory 
      Mail: P.O. Box 26732                             Shipping: 950 N Cherry Ave
            Tucson, AZ 85726-6732                                Tucson, AZ 85719

      Tucson Office Phone: 520-318-8486     FAX number: 520-318-8487