If the star names used in data files are not exactly the same character strings as those used in star files, the reduction program will try to make cross-identifications. These are based on heuristic rules that are generally observed in naming stars -- for example, many stars have a catalog abbreviation followed by a number, or a Greek letter followed by a constellation abbreviation. The program recognizes some common catalog abbreviations (HR, BS, BD, CD, CPD, HD, NGC), but will guess that two or three letters followed by a number represents such a name. It also can cope with common suffixes like A, B, and AB for multiple stars.
The program applies these rules in attempting to parse name strings containing multiple designations that are not separated by the `` = '' string (surrounded by blanks). If you sometimes write a name with an embedded blank and sometimes without (e.g., ``HR 123'' vs. ``HR123''), it may be able to identify the two as equivalent, or it may ask for help. It is difficult to write a simple set of foolproof rules for recognizing star names; for example, the program cannot simply squeeze out embedded blanks, as it would then confuse BD +1 2345 with BD +12 345.
Occasionally a typing error can confuse the program, and it will print Cannot parse: followed by a name string. For example, spelling errors in constellation abbreviations, Greek letters, or the letter O for a digit 0 can cause such a message. In these cases, the program asks for help, and asks for a replacement name string (which can contain embedded blanks). Afterward, the replacement string will be used instead of the one that caused problems.
This situation can be avoided by making sure that all star names are spelled consistently, and that names in star files agree with names in data files.