Introduction to Observing

This is a brief introduction to observing at the CSO. (It remains a work in progress.)


Please review the Safety Information, preferably at sea level. At least two people are required whenever anyone is at the telescope.


At the altitude of the CSO, 4070 m (13350 ft), the air pressure is only about 60% of the sea level pressure. Consequently everyone will experience some degree of hypoxia and may experience symptoms of altitude sickness. If you experience headache, light-headedness, dizziness, weakness, fatigue, nausea, vomiting, etc., tell your observing partners. If symptoms persist, descend to HP as soon as possible. If the symptoms are severe, call 911 or Simon or Diana and descend and seek medical attention in Hilo immediately.

Weather conditions

  • Stay aware of the weather conditions while observing. Look outside occasionally. There are many weather resources available, including the EAO weather summary.
  • In case of Adverse Weather, close the shutter. Remember it takes 10-15 min to close the shutter completely.
  • When observers are present at the telescope, any of the following conditions preclude observing. Close the shutter if any occur:
    • Relative humidity outside the dome above 80%.
    • Wind speed at the JCMT sustained above 35 mph (16 m/s).
    • Rain, snow, sleet, ice, fog, or other precipitation.
  • Remote observations require better conditions. Do not observe if any of these occur:
    • Relative humidity outside the dome above 60%.
    • Wind speed at the JCMT sustained above 30 mph (13 m/s).
    • Rain, snow, sleet, ice, fog, or other precipitation.
  • The CSO hygrometer and thermometer are mounted inside the dome. So if the shutter is closed, the temperature is usually higher and the relative humidity lower than outside.
  • The CSO does not have a working anemometer. As a proxy, watch the JCMT wind speed. If the JCMT anemometer is off line, watch the SMA wind speed.

Avoid the Sun

Do not let the Sun directly illuminate any part of the telescope structure. Check this visually and with the CSO webcams. When you start observing around sunset, keep the telescope pointed to the east (az 90). In the morning after sunrise, keep the telescope pointed to the west (az 270 or -90). Sunlight on the telescope structure will adversely affect the pointing and efficiency for you and subsequent observers.

Remote observations are allowed starting one hour after sunset and finishing one hour before sunrise.


  • Review the documentation. Procedures may change.
  • Prepare source and line Catalogs.
  • Check the Instrument status with the staff. The day crew may leave notes on the white board in the control room. If you want to use a different instrument than you specified in your proposal, please contact the Technical Manager, Simon Radford.
  • Check the clearance around the telescope. Make sure nothing will interfere with motion of the telescope or instruments. Check for ladders, oscilloscopes, etc., in the sidecab or on the alidade platform. During the week, the day crew will check before they leave but it's a good idea to check again.


After observing

  1. Close the shutter. This takes 10-15 min. When remote observing, please close the shutter before sunrise.
    UIP> shutter /close
    • If the shutter doesn't close, follow these instructions. Please report problems to the staff.
  2. Stow the telescope
    UIP> stow
    After sunrise, wait until the shutter is no more than 15% open before using the stow command. Please do not let the Sun directly illuminate any part of the telescope structure. Check the CSO webcams.
  3. Stop the secondary wobbler
    UIP> sec /stop
  4. Follow any instrument specific shutdown procedures:
  5. Stow any ladders or other equipment.
  6. Heterodyne observers please add your nightly pointing sheet to the end the log book and return the book to the bookshelf.
  7. Please submit an Observer Report.
  8. Logout from kilauea and other computers.
  9. Leave the control room tidy for the next observers.
  10. Turn off all the lights and heaters in the building. Lock both entry doors.

Drive safely!

cso/observing/operating.txt · Last modified: 2015-05-14 05:54 by sradford
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