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Description:
This attribute
specifies the geodetic altitude of the observer, in metres, relative to the IAU 1976
reference ellipsoid. The basic
Frame class makes no use of this attribute, but
specialised subclasses of Frame may use it. For instance, the
SpecFrame,
SkyFrame and
TimeFrame classes use it. The default value is zero.
Type:
Floating point.
Applicability
Frame
All Frames have this attribute.
SpecFrame
Together with
the
ObsLon,
Epoch,
RefRA and
RefDec attributes, it defines the Doppler shift introduced
by the observers diurnal motion around the earths axis, which is needed when
converting to or from the topocentric standard of rest. The maximum velocity error
which can be caused by an incorrect value is 0.5 km/s. The default value for
the attribute is zero.
TimeFrame
Together with the ObsLon attribute, it
is used when converting between certain time scales (TDB, TCB, LMST, LAST)
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A Library for Handling
World
Coordinate Systems
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