# Track curve files

Track lists (dependency of frame shift on observation time) are usually used for determining the value of periodic error of the telescope mount. A track curve table consists of observation time in Julian date form followed by shifts in the horizontal (X) and the vertical (Y) axes in pixels relative to the reference frame.

Output files are stored in the ASCII format; the end of the line is represented by `CR+LF` in the DOS/MS Windows environment and by `LF` in the Unix/Linux environment. First line contains a list of column names separated by single space character. Second line consists of additional information and has no special formatting, it must not start by number, though.

On the following lines, the table values are stored. The values are separated by tab character or single space, rows are separated by the end-of-line character (see above). Parsers must ignore all additional white characters. Empty lines indicates, that the corresponding frame was not successfully processed and thus shift values could not be determined. See table 1 for short description of columns.

Table 1

Keyword | Description
--- | ---
JD | Geocentric Julian date of observation
OFFSETX | Relative shift in horizontal direction
OFFSETY | Relative shift in vertical direction