User's Guide to the Lick 36" Refracting Telescope

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Dome Lighting

Dome lighting is an important safety element when operating the 36". Most of the in-dome (not on the telescope) lighting is controlled from the desk console (Figure 1). Having the appropriate amount of lighting on in the dome greatly affects viewing for both the astronomers and public as well as safety. Lighting that is available includes:

  • Tomb, exit and under floor lights - Figure 2 (switch panel) and Figure 4
  • Dome lights (white lights high on the dome walls) - Figure 3
  • Wall lights (red lights just above standing height on the mezzanine level) - Figure 4
  • White desk lights (white lights just above the desk controls) - Figure 5
  • Red desk lights (red lights in the same fixture as the white desk lights) - Figure 6
  • South floor lights (red lights at pier spiral stairway) - Figure 7
  • Balcony floor lights (red puck lights at the edge of the balcony floor - Figures 4 and 8 and stair lights - Figure 4)
  • Outside stair way lights (red) - Figure 9 (switch panel)

Figure 1: Desk lighting controls

Each of the above mentioned lights (except the tomb et al. and outside stairway lights) are controlled by a toggle switch from the control desk pictured in Figure 1. The lights are labeled and most also have on/off positions indicated. The tomb lights are now labeled and are controlled by the light switch panel near the door on the right hand side (looking out). The left switch turns on one set of under floor lights, the middle switch turns a different set of under floor lights, and the right switch turns on red exit lights and the tomb light. The outside stair lights are controlled by a single switch at the bottom of the outside stairway.

Figure 2: Light switch plate for exit, tomb, and under floor lights. A second set of these switches is by the upstairs door inside the dome.

Recommended Lighting Levels

Science observations
This is determined completely by the type of observations required. Typically, no lights will be on and all window shutters closed to eliminate stray light in the dome. No guests are usually allowed due to safety reasons in this case.

Public events and tours
The default lighting choice is: the red wall lights, balcony floor lights, south floor lamps, red desk lamp, tomb and exit sign lights, and outside stairway red light. Sometimes you may want the white desk lamp, particularly if you have information on the object being viewed through the telescope available for the public to read. You may also want the underfloor lights on if you want to highlight the mechanical structure of the floor. Modifications to this lighting option are described below.

Public tours first entering the dome
When the public first enters the dome all of the lighting should be on. It is sometimes desirable (for dramatic effect) to keep the white dome lights off during tours until all of the attendees are seated. If this approach is used the host astronomer needs to guide people along the mezzanine with a flashlight and make sure the public knows that there is a drop-off and that the railing will not prevent a fall. During public events, the white lights are usually off, requiring docents to escort the public when they enter the dome for safety.

The Moon
The moon is too bright for the public to look at without having some white light on. Preferably the white dome lights will be on, but just the white light of the desk is also an option. If only the desk light is on and you will be looking at other objects be sure to recommend that they look with their non-dominant eye so that they can use their dominant eye for the other objects.

Bright Objects
Saturn and Jupiter can be viewed with the white desk lamp on. Mars, Venus and bright binary stars can also be viewed with the white desk lamp on.

Medium Brightness Objects
Medium bright objects should be viewed with the red desk lamp on. Visitors eyes should be adapted to the darkness at this point and shouldn't notice the white light missing. Objects considered medium brightness could include clusters, dimmer planets, bright planetary nebulae, etc.

Dim Objects
Dim objects can be view with the red desk lamp on but it is often desirable to turn it off. The shade over the first floor door should also be pulled and the tomb/under floor lights should also be turned off. Objects in this category include dim nebulae, galaxies, faint comets, etc.

Figure 3: Dome lights (white)

Figure 4: Wall lights (red), balcony floor lights, exit light, and stair lights

Figure 5: Desk lighting (white).

Figure 6: Desk lighting (red)

Figure 7: South floor lights

Figure 8: Mezzanine (balcony) floor lighting (red)

Figure 9: Outside stair lights (red)