learned how to create stars like this from Yetziratic Magic. the trick: any number divisible by 3 can create similar stars. if you want to create a 21-rayed star, multiply 21 by 3, arrange the numbers 1 to 63 in a magic square (i know i know, it's a rectangle) where all the columns equal the same number. take last row, write numbers clockwise on a circle, begin with lowest number: connect-the-dots.
formula to get all columns with same values is pretty simple. while it took me hours to figure out, i'm happy to save you hours of schizoid trouble.
 select your odd numby, that's the number of points in your star.
 n x 3 = P, multiply your number by three, eg, 21 x 3 = 63
 fire up Excel so you don't have to add manually
 first row: n to P, or using our example:
note: first row should end with your number
 11 in brackets indicates MIDDLE NUMBER
 second row: take the number AFTER your number,
place it under the MIDDLE NUMBER, eg, 22.
 continue counting to the end of the row.
 begin 2nd row, 1st position, continue.
 third row: place P (or 63) as middle number.
 subtract 1 from P: P - 1 = E, eg, 63 - 1 = 62.
 begin 3rd row, 1st position with E, eg, 62.
 counting backwards, subtract 2 and enter EVEN numbers.
 that should get you to P (or 63).
 subtract 2 from P: P - 2 = E, eg, 63 - 2 = 61.
 to complete the row, enter ODD numbers after P (or 63).
 counting backwards, subtract 2 and enter ODD numbers.
all column totals should equal the same number. to draw the star:
 draw a circle.
 it's easier if you use Excel.
 top of circle, place first number on the third row (62).
 place remaining numbers clockwise.
 locate smallest number (43).
 use Curve Line drawtool on Excel's AutoShapes
 click on 43, click on 44, keep counting & clicking until you return to 43.
excel usually can draw a nice star for you. may take a few tries tho. when you get the shape you like, color it and stuff and you got your star.