The HEALPix documentation is currently available for downloading in pdf and can be browsed in html

The HEALPIX primer pdf
(0.53 MiB)
html

 
HEALPIX Facility Installation Guidelines pdf
(0.38 MiB)
html

 
HEALPIX Fortran90 Facilities User Guidelines pdf
(0.59 MiB)
html

 
HEALPIX Fortran90 Subroutines Overview pdf
(0.75 MiB)
html

 
HEALPIX IDL Facilities Overview pdf
(1.50 MiB)
html

 
HEALPIX C Subroutines Overview pdf
(0.15 MiB)
html

 
HEALPIX C++ Facilities and Subroutines Overview   html

 
HEALPix Java Overview   html

 
HEALPix Python Overview (healpy)   html