| APER | Circular APERture photometry |
| CNTRD | Obtain the centroid of a star by locating where derivatives go to zero |
| DAOERF | Calculate the intensity, (and optionally, the derivatives) of a bivariate Gaussian, integrated over pixels. Called by DAO_VALUE |
| DAO_VALUE | Obtain the value of a DAOPHOT PSF function at a given set of points |
| FIND | FIND point sources within an image |
| GCNTRD | Determine centroid by Gaussian fits to the marginal X,Y distributions |
| GETPSF | Obtain a PSF (Gaussian + residuals) from isolated stars. |
| GROUP | Place stars with non-overlapping PSF's in distinct groups |
| MMM | Mean, Median, Mode) sophisticated sky background computation |
| NSTAR | Simultaneous PSF fitting of a group of stars |
| PIXWT | Compute the area of the intersection of a circle on a rectangle |
| PKFIT | Fit a Gaussian + residuals to a isolated star (called by GETPSF) |
| RDPSF | Read a PSF file that was created by GETPSF into an IDL array. |
| RINTER | Cubic Interpolation at a set of reference points, optionally obtain derivatives. (in /image) |
| SKY | Compute image sky level using MMM |
| SRCOR | Correlate the source positions in two different lists |
| SUBSTAR | Subtract a scaled PSF at specified star positions |
| T_APER | Driver procedure for APER with I/O to a disk FITS ASCII table |
| T_FIND | Driver procedure for FIND with I/O to a disk FITS ASCII table |
| T_GROUP | Driver procedure for GROUP with I/O to a disk FITS ASCII table |
| T_GETPSF | Driver procedure for GETPSF with I/O to a disk FITS ASCII table |
| T_NSTAR | Driver procedure for NSTAR with I/O to a disk FITS ASCII table |
| T_SUBSTAR | Driver procedure for SUBSTAR with I/O to a disk FITS ASCII table |