calculateImageParallacticAngle

lsst.ip.diffim.calculateImageParallacticAngle(visitInfo, wcs)

Calculate the total sky rotation angle of an exposure.

Parameters

visitInfolsst.afw.image.VisitInfo

Metadata for the exposure.

wcslsst.afw.geom.SkyWcs

Coordinate system definition (wcs) for the exposure.

Returns

lsst.geom.Angle

The rotation of the image axis, East from North. Equal to the parallactic angle plus any additional rotation of the coordinate system. A rotation angle of 0 degrees is defined with North along the +y axis and East along the +x axis. A rotation angle of 90 degrees is defined with North along the +x axis and East along the -y axis.