#### Description:

This attribute gives the longitude of the reference point of the FITS-WCS projection implemented by a WcsMap. The value is in radians in the `"` native spherical`"` coordinate system, and will usually be zero. See the description of attribute NatLat for further information.

The NatLon attribute is read-only.

Type:

  Floating point, read-only.

#### Applicability

##### WcsMap

All WcsMaps have this attribute.
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