[Haskell-beginners] map increases length of list

[Aaron MacDonald]

For some reason, the map function returns a list that has one more  
element than my input list.

My input list is a range defined by [0, 60..359] (should translate  
into [0,60,120,180,240,300]).

The function I'm giving to map is defined this way:
-----
degreesToRadians :: Double -> Double
degreesToRadians degrees = degrees * (pi / 180)
-----

This is how I'm calling map overall:
-----
 > map degreesToRadians [0,60..359]
[0.0,1.0471975511965976,2.0943951023931953,3.141592653589793,4.1887902047863905,5.235987755982989,6.283185307179586 
]
-----

As you can hopefully see, there are seven elements instead of six.  
Getting the length confirms this:
-----
 > length [0,60..359]
6
 > length $ map degreesToRadians [0,60..359]
7
-----

I do not seem to get this behaviour with the length if I either  
substitute the degreesToRadians function or substitute the [0,60..359]  
range.

P.S. Is there a built-in function to convert degrees to radians and  
vice-versa?