Updated README.md
Updated README.md
Fixed bug with logpage EXIF timestamp conversion
Parsing of plate CSV files using plate_id when WFPDB files are present
Added timestamp columns to all database tables
Fixed bug with database definition
Combining of global and local RA/Dec
Use numpy.nan for missing RA/Dec
Check for nan values before cross-matching with UCAC4
Fixed bug with wrong method name
Handle numpy.nan values during writing to the database
Convert RA/Dec to XYZ, update database structure
Handle missing healpix value
Fixed typo
Fixed bug with negative healpix not converted to None
Implemented healpix calculation
Fixed bug with healpix calculation
Fixed bug with healpix calculation
Renamed healpix8 with healpix256
Store results of source cross-match with UCAC4