FIGURE 4. Telescope coordinate systems looking towards sky (Left Nasmyth focus)
See Telescope coordinate systems looking towards sky (excludes Nasmyth foci) excluded Nasmyth foci, which have an extra elevation angle dependence owing to the fact that the instrument is not mounted on the telescope. The sign of this dependence is opposite at the two Nasmyth foci. This means that, while individual pictures are useful for promotion of physical understanding, software coordinate transformations can apply to all focal-stations if the sign of the elevation dependence is set as follows:
See Telescope coordinate systems looking towards sky (Left Nasmyth focus) and See Telescope coordinate systems looking towards sky (Right Nasmyth focus) are versions of See Telescope coordinate systems looking towards sky (excludes Nasmyth foci) for Left and Right Nasmyth foci respectively. They differ from See Telescope coordinate systems looking towards sky (excludes Nasmyth foci) only in that a new "local vertical" line has been introduced, from which the rotator and elevation angles are measured.
FIGURE 4. Telescope coordinate systems looking towards sky (Left Nasmyth focus)
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FIGURE 5. Telescope coordinate systems looking towards sky (Right Nasmyth focus)
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