The Moc class describes an arbitrary collection of cells on the sky, whereas other subclasses of Region describe exact geometric shapes in any arbitrary domain. This results in some differences between Mocs and other types of Region, the main one being that Mocs have no associated uncertainty.
The MOC recommendation requires that a MOC always describes a sky area using the ICRS coordinate system. However, the Moc class, like other subclasses of Region, allows its attributes to be changed so that it represents the equivalent area in any celestial coordinate system that can be mapped to ICRS. See attribute Adaptive.
In practice, to use this class an empty Moc object (i.e. a Moc describing a null area of the sky) should first be created using the astMoc constructor. Areas of the sky should then be added into the empty Moc using one or more of the class methods.
If it is required to write a Moc out to a FITS binary table, the data value and headers to put in the table can be obtained using methods astGetMocData and astGetMocHeader The MOC described by an existing FITS binary table can be added into a Moc object using the astAddMocData method.
Note, this class is limited to MOCs for which the number of cells in the normalised MOC can be represented in a four byte signed integer.
MaxOrder: the highest HEALPix order used in the MOC
MaxRes: the best resolution of the MOC, in arc-seconds
MinOrder: the lowest HEALPix order used in the MOC
MinRes: the worst resolution of the MOC, in arc-seconds
MocArea: the area of the MOC
MocLength: the table length used to describe a MOC in FITS
MocType: the data type used to describe a MOC in FITS
astAddCell: Adds a single HEALPix cell into an existing Moc
astAddMocData: Adds a FITS binary table into an existing Moc
astAddMocString: Adds a JSON or string-encoded MOC into an existing Moc
astAddPixelMaskX: Adds a pixel mask to an existing Moc
astAddRegion: Adds a Region to an existing Moc
astGetCell: Identify the next cell included in a Moc
astGetMocData: Get the FITS binary table data describing a Moc
astGetMocHeader: Get the FITS binary table headers describing a Moc
astGetMocString: Get the JSON or string-encoded form of a Moc
astTestCell: Test if a single HEALPix cell is included in a Moc