Plotting Sources on an all-sky Aitoff Grid

 

To plot the distribution of sources on an all-sky map (Aitoff projection) the two commands PLOT/AITOFF and OVERPLOT/AITOFF are necessary. The first command plots the Aitoff grid into the graphics window:

PLOT/AITOFF [ratio]

 

• ratio : x/y axis ratio. The default is 2.0

To plot sources into that grid the second command OVERPLOT/AITOFF is used:

OVERPLOT/AITOFF table long_col lat_col stype [ssize] [colour]

 

• table is the name of the table containing source longitudes and latitudes (degrees). Longitude and latitude can be in any coordinate system.
• long_col is the name of the column containing the longitudes. Specify as :LABEL or by its number (e.g. #15). No defaults.
• lat_col is the name of the column containing the latitudes. Specify as :LABEL or by its number (e.g. #16). No defaults.
• stype is the symbol type. Equivalent to parameter stype of command SET/GRAPHICS. See HELP SET/GRAPHICS for available symbols.
• ssize is the symbol size. Equivalent to parameter ssize of command SET/GRAPHICS. Defaulted to 1.
• colour is the symbol color. Equivalent to parameter colour of SET/GRAPHICS. See HELP SET/GRAPHICS for available colors. Defaulted to 1 (black).

Now, let's produce a nice all-sky plot of our sources. The color and line attributes of the grid can be set using the command SET/GRAPHICS. To open a graphics window and plot a blue Aitoff grid with thick lines use the following command sequence

CREATE/GRAPHICS
SET/GRAPHICS colour=4 lwidth=4
PLOT/AITOFF

Assume that we have a table quasars.tbl containing quasar positions in columns :LONG and :LAT. In this table we also have a column identifying these quasars as radio-quiet (:RADIO.eq."QUIET") or radio-loud (:RADIO.eq."LOUD"). We want to plot the different types of quasars with different symbols into the Aitoff grid. We reset the line width and plot the radio-quiet ones with filled green triangles of half the default size first.

SET/GRAPHICS lwidth=1
SELECT/TABLE quasars :RADIO.EQ."QUIET"
OVERPLOT/AITOFF quasars :LONG :LAT 20 0.5 3

Now we plot the radio-loud quasars with slightly larger (75% of the default) red squares:

SELECT/TABLE quasars :RADIO.EQ."LOUD" 
{OVERPLOT/AITOFF quasars :LONG :LAT 3 0.75 2

This was just an example. We take no responsibility for the aesthetic appearance of the plot...