Changes between Version 14 and Version 15 of Dvo_tutorial

Timestamp:

May 7, 2009, 11:14:33 PM (17 years ago)

Author:

Sebastian Jester

Comment:

add cmd example

Dvo_tutorial

@@ -214 +214 @@
 See source:trunk/psModules/src/objects/pmSourceMasks.h for possible flag values
 
+== Make a colour-colour and colour-magnitude diagram of a stellar locus ==
+
+{{{
+ region 17 35 2
+ avextract RA DEC g g:err r r:err z z:err 
+ # Define a logical vector to filter out "good" objects 
+ # Normally want to avextract & check the 'flag' vector, too, but 
+ # at the moment flag seems to be all 0
+ set in = g<20 && g:err<0.2 && r:err < 0.2 && z:err & 0.2
+ # Compute colours
+ set gr = g-r
+ set rz = r-z
+ # Filter subsets
+ subset gr_good = gr if (in)
+ subset rz_good = rz if (in)
+ # Plot a colour-colour diagram
+ limits -1 3 -1 2
+ box
+ plot gr_good rz_good
+ # Write vectors to file
+ write -f "%9.6f %9.6 %6.3f %6.3f %6.3f %6.3f %6.3f %6.3f" PS1_17_35.dat RA DEC g g:err r r:err z z:err
+ # Filter out nans
+ !grep -v 'nan' PS1_17_35.dat > PS1_17_35_clean.dat
+}}}
+
+To get a control sample of the same region from SDSS, run this SQL query via the [http://cas.sdss.org/astrodr7/en/tools/search/sql.asp SDSS sql search] 
+(the flag-checking part is the official recommendation from [http://cas.sdss.org/astrodr7/en/help/docs/realquery.asp#flags SDSS sample query])
+{{{ 
+select psfmag_g, psfmagerr_g, psfmag_r, psfmagerr_r, psfmag_z, psfmagerr_z into mydb.PS1_compare_CMD from star
+where ra between 15 and 19
+and dec between 33 and 37
+AND ((flags_r & 0x10000000) != 0) 
+AND ((flags_r & 0x8100000c00a4) = 0) 
+AND (((flags_r & 0x400000000000) = 0) or (psfmagerr_r <= 0.2)) 
+}}}
+
+AND (((flags_r & 0x100000000000) = 0) or (flags_r & 0x1000) = 0)
+
 = Things we want to know/do =