NOTES: 1,2. Target coordinates should be J2000 and in sexagesimal format.
3. A space-separated list of the spectral types;
an "A" matches all A* type stars, while A2 will only return A2 type stars.
4. If observation duration > 0, return two sets of standards, one for before and one for after the science target.
5. Appropriate magnitudes are converted from the Hipparcos V-band magnitudes using standard dwarf colors.
Acceptable filters are V, H, L, and M.
6. Maximum distance for acceptable standards.
Currently searches 18,999 O-K dwarfs.