README for creating synoptic maps:

-- The IDL program displaysynoptic.pro, located in /scr21/jsoc/hmi/synoptic, will take an mdi or hmi magnetogram and create a .ps file that applies a color table (HMI.MagColor.IDL_256.lut) and adds labels. The program is well-commented; take a look inside the program to see how to run it and what it does.

-- The code (displaysynoptic.pro) and colortable (HMI.MagColor.IDL_256.lut) used to generate the maps are in the same directory. Even though the colortable in the directory has 256 colors, the top and bottom bytes are reset to black and white inside of my code. I used the following formula to byte-scale the image:

f(x) = ax + b
a    = 253/3000.
b    = 127.5

By byte-scaling the image in this fashion, the four bins of grey colors are exactly symmetric about zero. As such, we can see the same structure in the weak field as we do in the associated .fits data. 


Monica Bobra