NAME: onchip PURPOSE: (one line) Extract and optionally plot differential on-chip photometry. DESCRIPTION: This program will read an altlog photometry file as generated by basphote and extract one object from the file, compute differential photometry for the program object (Serial #0000) against the field stars. CATEGORY: Photometry CALLING SEQUENCE: onchip,logname,objname,filter,object,primary,others,jd,time,mag,err INPUTS: logname - Name of the altlog format photometry file to read. objname - String with the exact name of the object to extract. filter - String containing the filter code to extract. object - Serial number of the object to extract. primary - Serial number of the on-chip reference star to use as the primary reference. others - Serial number(s) of the other on-chip stars to use as a check of the primary reference. Scalar or vector. If set to -1, no secondary references are used. OPTIONAL INPUT PARAMETERS: KEYWORD PARAMETERS: BARS - Flag, if true, extend major ticks across plot (default=false) MAGPRI - Magnitude of primary reference star (default=0). NOPLOT - When set will inhibit generating a plot to the current plot device. (same as /NOPOS and /NOPHOT together). NOPOS - No plot of the positions. NOPHOT - No plot of the photometry. COLORS - Colors to use for the plot. colors(0) = axis, program object, (primary standard) default = !d.n_colors-1 colors(1) = primary standard, default = 1 colors(2) = secondary standard 1, default = 2 colors(3) = secondary standard 2, default = 2 and so on. COLORS should have as many elements as needed for the object, primary standard, and all secondary standards. NOERRBAR - Flag, if set suppresses error bars on star check mag plot SHOWALL - Flag, if set, prints out all the relevant mangitudes to allow seeing which mags are being used. TIMEUNIT - Select time units to plot on x-axis, 0 - UT hours (default) 1 - JD (decimal days) UPPERCASE - Flag, if true, forces object names and filter names to upper case. OUTPUTS: jd - Julian date of observation. time - UT of observation, decimal hours. (or JD, depending on TIMEUNIT) mag - reduced magnitude of program object. err - Uncertainty of the magnitude. COMMON BLOCKS: SIDE EFFECTS: RESTRICTIONS: PROCEDURE: MODIFICATION HISTORY: 2/4/93, Written by Marc W. Buie, Lowell Observatory. 6/29/93, MWB, added filter argument. 96 Mar, MWB, added MAGPRI keyword 96/06/15, MWB, improved the plotting output for the photometry plot. 96/08/24, MWB, added TIMEUNIT and BARS keywords 96/10/31, MWB, added "bad" flag support from rdphalt 97/09/20, MWB, added UPPERCASE flag.