#-----------------------------------------------------------------------------
# IRACproc: IRAC Post-BCD Processing v4.3 PHOTOMETRY QUICK REFERENCE
#-----------------------------------------------------------------------------
(c) 2005 Mike Schuster, Massimo Marengo (mmarengo@cfa.harvard.edu)
(c) 2005 SAO - Smithsonian Astrophysical Observatory

Harvard-Smithsonian Center for Astrophysics
Smithsonian Astrophysical Observatory

16 JAN 2007

See HOWTO_PHOT for more detailed instructions.

#-----------------------------------------------------------------------------
# Assumptions
#-----------------------------------------------------------------------------
Zero-Point Determination**
------------------------
pixel scale = 1.22/sqrt(2) = 0.8626716"/pix
image units are DN/s
zero-points are for pre-S11 calibration
photometry is done with apertures
aperture has a radius of 4 pix
annulus has an inner radius of 14.1 pixels and a width of 14.1 pixels

** do_nsfind.cl and do_nsphot.cl can be modified to work with other IRAC data

#-----------------------------------------------------------------------------
# Preparing Images
#-----------------------------------------------------------------------------
This step is for preparing the images for photometry by converting the pixel 
units to DN/s.

Change dir to the target for which you wish to perform photometry:

user_name][ cd proc_dir/analysis/

Start PDL.

user_name]analysis[ perldl

Example, convert MJy/sr -> DN/s:

perldl> cropout_bcd('I1_NAME.fits','I1_NAME_dns.fits',{MJSR2DNS=>1})
perldl> cropout_bcd('I2_NAME.fits','I2_NAME_dns.fits',{MJSR2DNS=>1})
perldl> cropout_bcd('I3_NAME.fits','I3_NAME_dns.fits',{MJSR2DNS=>1})
perldl> cropout_bcd('I4_NAME.fits','I4_NAME_dns.fits',{MJSR2DNS=>1})

Quit PDL - you will need to restart for the next target.

perldl> quit

#-----------------------------------------------------------------------------
# Gather Input Information for Photometry
#-----------------------------------------------------------------------------
Start IRAF and Ds9.

user_name][ cd proc_dir/analysis/
user_name][ ds9 &
user_name][ cd ~/iraf/
user_name][ cl

cl> cd proc_dir/analysis/
cl> imexam I1_NAME_dns.fits nlst=13 ncst=13
cl> imexam I2_NAME_dns.fits nlst=13 ncst=13
cl> imexam I3_NAME_dns.fits nlst=13 ncst=13
cl> imexam I4_NAME_dns.fits nlst=13 ncst=13

Move the cursor over the image display. Place the cursor on "blank sky" areas 
and press the "m" key. You will see image statistics for a box centered on 
the location of the cursor. Do this at several locations across the field 
(5 to 6+), and 2 to 3 times at each location (with slight shifts to weed out 
bad areas). You should find some consistency in the standard deviations that 
print at the IRAF command prompt. Average the standard deviations, ignoring 
values that are obviously low/high. A box size of 11x11, or 13x13, works well 
(set by nlst=11 ncst=11).

Record the sky sigma value for each channel.

#-----------------------------------------------------------------------------
# Measure Photometry
#-----------------------------------------------------------------------------

cl> run_nsphot

This script will identify possible sources, perform photometry and convert 
image coordinates to WCS for any of 4 channels. You will be prompted for the 
following parameters: "File Name" - everything in the image filename after 
"I<CH>_" and up to ".fits"; "exptime" - the exposure time for the image (same 
for all channels); "sig*" - the sky sigma values for each channel determined 
in the previous step; "dmin*" and "dmax*" - the minimum and maximum good data 
values (default INDEF).

#-----------------------------------------------------------------------------
# Correlate Photometry
#-----------------------------------------------------------------------------

user_name][ cd proc_dir/analysis/
user_name]analysis[ correlate -s 2

This script will correlate magnitudes and errors based on WCS coordinates for 
up to 4 channels. Low-quality data can be excluded from the final lists with 
either option -e (max error) or -s (min S/N). If the maximum absolute average 
differential in arcseconds for any channel is > 0.01, then increase the 
number of iterations with the -N option.

USAGE:  perl correlate.pl [--help][--ver][--t tolerance][--N max_iter]
                          [--r radius][--b boxscale][--a]
                          [--e max_error][--s min_S2N]
                          [--c red_color_cut]
                          [--phot phot_file_root]
                          [--wcs wcs_file_root]
                          [--o output_file_root]

The output files are phot.all and phot.red (sources with m[3.6]-m[4.5] >= 
red_color_cut, provided those channels are present), ds9 region files 
phot.all.reg and phot.red.reg, and a log file phot.log.