NAME: basphote PURPOSE: (one line) Circular aperture photometry extraction from images. DESCRIPTION: CATEGORY: CCD data processing CALLING SEQUENCE: Basphote,gain,image,exptime,xloc,yloc,radius,sky1,sky2,logfile[,objnum] INPUTS: gain : Gain of the CCD. Photons per count (DN). image : CCD image array. exptime : Exposure time for the image in seconds. xloc, yloc : Current location of the cursor in image coordinates. radius : Current aperture radius in pixels. sky1 : Inner radius of the sky annulus (in pixels). sky2 : Outer radius of the sky annulus (in pixels). If sky2<0 then sky1 is taken to be the actual sky signal in DN/pixel and |sky2| is the error on the sky. logfile : Name of the photometry log file. OPTIONAL INPUT PARAMETERS: objnum : Starting serial number for object in frame, default=0 If supplied as a scalar it will be incremented by the number of positions supplied in xloc/yloc. If given as a vector, will specify the exact number to and there will be no incrementing when done. KEYWORD INPUT PARAMETERS: (default on flags is false): AIRMASS - Optional airmass value. ALTLOG - Flag, if set, output is generated in an alternate format. BAD - Flag (or array) marking data as bad, default=good BOXMRAD - Size of the box to look for local max in. Default=radius[last value]. If boxmrad is negative, then the call to BOXM that finds the local max is suppressed. In effect, basphote assumes that the input location is already the maximum. CALCFWHMSIZE - Size of the area to compute the FWHM over, default=radius[last value]. This is especially important to set if you want a tight search for the maximum but still want an accurate FWHM (this happens when boxmrad<
Do not generate any screen output. ZPOINT - Optional zero point. KEYWORD OUTPUT PARAMETERS: ERR - Optional return of the magnitude error. FLERR - Uncertainty (1 sigma) of object flux. FLUX - Object flux (photons per second) FWHM - FWHM of object image(s), in arcsec if PSCALE provided, otherwise returned in pixels ONCHIP - Byte array of flags that indicate if object was on-chip. OUTJD - Optional output of Julian dates (for cubes). This will be a vector of length rank(image). Contents are computed from the input Julian date (JD=) and the input delta-time (DT=). MAG - Optional return of the instrumental magnitude. MAX - Optional return of peak signal in object. SKYMEAN - Optional return of sky signal, counts/pixel. SKYERR - Optional return of sky signal uncertainty, counts/pixel. This number is the standard deviation of the mean. SKYSIG - Optional return of the standard deviation of the sky signal. XCEN - Optional output of centroid x-position(s). YCEN - Optional output of centroid y-position(s). OUTPUTS: All output is sent to the screen and the logfile. Selected variables are returned via optional keywords. COMMON BLOCKS: None. SIDE EFFECTS: RESTRICTIONS: PROCEDURE: MODIFICATION HISTORY: Ported by Doug Loucks, Lowell Observatory, 1992 Oct from the C-language version written by Marc Buie. 93/6/1, Marc W. Buie, Lowell Observatory, added the alternate logfile format to the program. Streamlined the required input parameters. Calling sequence is now different. 1/25/93, MWB, changed default on boxmrad to be the LAST value in the radius vector. 2/3/93, DWL. Moved the file format declarations outside of the main loop. 2/4/93, DWL. Modified to accept all valid combinations of scalar and vector values for xloc, yloc, radius, sky1, and sky2 inputs. 2/4/93, DWL. Added checks for 'seeing' sub-array extraction. 2/4/93, DWL, Added keywords XCEN and YCEN to allow return of the refined center(s) to the calling program. Also, xcen, ycen, xmax, and ymax will be vectors if xloc and yloc are vectors. 2/10/93,DWL, Removed XMAX and YMAX keywords. 2/10/93,DWL, Added checks for off-chip and too-near-edge conditions. 4/21/93,DWL, Added keywords MAG and ERR. The instrumental magnitude and uncertainty are returned to the caller if these keywords are present. If the inputs xcen and ycen are vectors, these variables will also be returned as vectors. 5/21/93, MWB, Fixed variables that are undefined if off-chip condition is found. Dummy values are set to prevent printouts from dying. 5/26/93, MWB, Added FLUX, FLUXERR, and NOLOG keywords. Fixed bug on computation of sky background error, errant gain factor removed. 9/30/93, MWB, Modified usage of NAME to allow vector input. 2/2/1994, DWL, Mods to allow 3-D image cube photometry. Also added OUTJD keyword. 4/28/94, MWB, Fixed bug that recomputed a new centroid position if the EXACT flag was set. This had NO effect on photometry. 8/30/94, MWB, Added ONCHIP and PRINTALL keywords. 5/18/95, MWB, Added FWHM optional output keyword. 6/16/95, MWB, If PSCALE negative, fwhm not computed. 1/8/96, MWB, Added override on serial number, objnum can now be a vector. 7/13/96, MWB, changed FWHM calculation to remove function fitting. 10/31/96, MWB, added BAD= keyword for flag pass through 3/17/97, MWB, added MAX keyword 97/09/10, MWB, removed extraneous sub-expression evaluation (5x faster). 98/03/04, MWB, Added SKYMEAN, SKYERR return keywords. 98/09/21, MWB, added suppression of BOXM call through a negative BOXMRAD. 2000/01/18, MWB, added SKYSIG return keywords. 2000/06/02, MWB, upgrade to photometry log file version that includes sky measurement. 2001/01/25, MWB, fixed bug in certain cases when overriding the object serial number. Also took out all "message" calls to make sure info and warning messages are seen. 2004/07/15, MWB, changed loop variables to LONG. 2006/04/19, MWB, fixed bug in ALTLOG usage for upgrading photometry files 2006/04/26, Peter L. Collins, Lowell Observatory, upgrade to include and log CCD readout noise (keyword RDNOISE). The log level is promoted to v1.1 from v1.0. 2006/05/22, PLC, added another way to default the rdnoise, using keyword RDNOISE=v where v is some negative value- as a convenience to other code. 2008/03/25, MWB, fixed minor bug related to an aperture that falls off chip 2010/12/20, MWB, minor tweak to prevent negative photon noise. 2011/12/23, MWB, added CALCFWHMSIZE keyword, this is an inportant change, read the documentation on this keyword. If you ever used BOXMRAD with a value much smaller than RADIUS you really need to read the new documentation. 2013/07/06, MWB, added RADP keyword option 2013/07/29, MWB, fixed a bug for normal FWHM calculation introduced when RADP option was added.