查看“天图投影上的圆”的源代码

*On the atioff projection map, how to draw a circle (e.g. telescope field of view)? suppose, telescope pointed at (Ra0,Dec0), FOV is a circle with radius R0
#Change the coordinate system from celestial to the designed coordinate (pole at Ra0,Dec0).
#Then the circle in the new coordinate system is simply DecP=90-R0
#change the new coordinate system back to celestial
* IDL code(在天球投影上画出一个中心在Ra，Dec，半径为2.5度的圆）
 Rad=2.5
 fRa=indgen(360)*1.
 fDec=fRa*0+90-Rad
 change_cor,fRa0,fDec0,fRa,fDec,Ra,Dec,0,2 ;my own code[[文件:Change cor.pro.txt]]
 aitoff,fRa0,fDec0,x,y
 aitoff_grid,60,/label
 cgplots,x,y,psym=3,color='red'