== PGC55 ==

pgc55 
RA:  0.15583   
Dec: 33.60094  
Ra = 0.67 (arcmin)
Rb = 0.20 (arcmin)
PA = 13.12 (degrees)

# position angle (PA)  [Degrees: Up=0, Left=90]"
{{{
run_sex <root> <ra> <dec>
./run_sex.csh pgc55_g 0.15583 33.60094
}}}

= SExtractor first outputs = 

||filter || RA || DEC || MAG || Re || Ra  || Rb  || b/a || PA  || 
|| || deg || deg || mag || arcmin || arcmin || arcmin ||  ||  deg || 

|| pgc55_u || 0.1555 || 33.6014 || 17.03 || 0.17 || 0.75 || 0.20 || 0.27 || 9.30 || 
|| pgc55_g || 0.1555 || 33.6013 || 16.10 || 0.15 || 0.67 || 0.20 || 0.30 || 13.12 || 
|| pgc55_r || 0.1555 || 33.6012 || 15.74 || 0.15 || 0.63 || 0.20 || 0.31 || 13.20 || 
|| pgc55_i || 0.1555 || 33.6012 || 15.53 || 0.14 || 0.65 || 0.20 || 0.31 || 13.53 || 
|| pgc55_z || 0.1555 || 33.6012 || 15.61 || 0.12 || 0.50 || 0.14 || 0.28 || 12.21 || 


GLGA-qa

{{{
minskywid = 27. / as_pix	 ; 27 arcsec is minimum sky width
factor = 1.5                     ;  1.5 default
skyinner = factor*semimajor
skyouter = semimajor*sqrt(1+factor^2) > (skyinner+minskywid)  


Sigma multiplier for thresshold (default =  2.5): 2.0
Magnitude faint limit (default =  24.0): 25
}}}

I increased the aperture size, until the difference between APR and ASY magnitudes are less than 0.05 mag.

= SKY =

 * u
{{{
final sky/px, skyerr/px     [mJy/px]:    0.00068215   0.00010009
final musky, muskyerr  [AB mag/as^2]:     22.304     0.159
}}}

 * g
{{{
final sky/px, skyerr/px     [mJy/px]:    0.00083100   0.00003426
final musky, muskyerr  [AB mag/as^2]:     22.090     0.045
}}}

 * r
{{{
final sky/px, skyerr/px     [mJy/px]:    0.00194121   0.00005404
final musky, muskyerr  [AB mag/as^2]:     21.168     0.030
}}}

 * i
{{{
final sky/px, skyerr/px     [mJy/px]:    0.00371400   0.00009490
final musky, muskyerr  [AB mag/as^2]:     20.464     0.028
}}}

 * z
{{{
final sky/px, skyerr/px     [mJy/px]:    0.01061923   0.00031765
final musky, muskyerr  [AB mag/as^2]:     19.323     0.032
}}}

[[Image(pgc55_sdss_profile.jpg)]] [[Image(pgc55_sdss_images.jpg)]]

----

= Changing the sky aperture =

Now, I keep everything the same but the size of the inner aperture


{{{
minskywid = 27. / as_pix	 ; 27 arcsec is minimum sky width
factor = 2.0                     ;  1.5 default
skyinner = factor*semimajor
skyouter = semimajor*sqrt(1+factor^2) > (skyinner+minskywid)  
}}}