Install calibration lamp

 A calibration lamp appropriate to the installed calibration filter should now be installed. Amongst the Fabry-Perot equipment, you will find Neon and Hydrogen calibration lamps, and their associated power supplies. The Neon lamp is significantly brighter than the Hydrogen one, and is therefore usually the best choice. One exception is when operating at the 200-inch telescope, where the current filter arrangements allow for only two filters. If the 6563Å H$\alpha$ filter is needed for science observations, use of the Hydrogen lamp will allow a second science filter to be used.

The calibration lamp is installed so that it will illuminate the inside of the dome. When a calibration exposure is required, the lamp will be turned on and the dome or dome shutters will be rotated to occult the telescope. The installation of the lamp is very different between the two telescopes:

• 60-inch
  The calibration lamp is operated manually at the 60-inch telescope. To make this procedure as easy as possible, the lamp is usually located on the platform over the elevator shaft. It is then plugged into the power strip on the west side of the elevator shaft, at the top of the stairs. This allows the observer to ascend the stairs and easily turn the lamp on or off, using the switch on the power strip, as opposed to a switch on the lamp power supply.

  In the case of the Neon lamp, the bulb should be taped securely to the railing above the elevator with a few pieces of glass tape. Its cord can then be plugged into the power supply, which should be placed on the floor. The Hydrogen lamp bulb does not have a cord and must be plugged directly into its power supply on the floor. Then plug the power supply into the power strip. Turn the power supply on, and test that you can then operate the lamp using the switch on the power strip.

  Also at this time, while you are on the platform over the elevator shaft, you may want to go ahead and remove the cover of the telescope. You will need to have someone turn on the telescope power in the control room (although not the pumps), and then slew the telescope north in declination, until you can reach up and remove the cover. The cover should be stowed in its usual position against the western railing. There are a pair of small metal bars there, which are used to hold the cover against the railing. Be sure that the telescope cover does not interfere with the calibration lamp, or cause any strong shadows to be cast on the dome. Leave the telescope tipped at an altitude of 45°-60°, where it can image a flat section of the dome. Be especially careful that the telescope field of view does not include any of the lamp fixtures on the inside of the dome.

• 200-inch
  The calibration lamp can be remotely operated at the 200-inch telescope. The Palomar crew should be asked to install the desired lamp and power supply in the prime focus cage of the telescope, in place of one of the standard lamps. The 200-inch complement of four lamps includes a pair of flat lamps (low and high), a UV lamp, and an arc lamp. You will probably want the staff to replace the UV lamp with the calibration lamp, since it is the least likely to be used with the Fabry-Perot. If you select to replace a different lamp, note that a few of the software programs, e.g., fpseq, will need to be modified to operate the appropriate lamp. The lamp installation may take some time, so be sure to remind the crew of this step early in the afternoon. Instructions on how to remotely control the lamps are provided in Section A.7.