# Place arrows around circumference of circle in TikZ

I am trying to place arrows around the circumference of a circle. I want 8 arrows around this circle; i.e. pointing North, North-east, East, South-east etc. The direction of the arrows should be perpendicular to the circumference of the circle (i.e. they are all pointing outwards).

I have seen this answer from How do I place nodes around a circle in Tikz?, but I couldn't figure out how to get it to work for me.

I have drawn one arrow to illustrate what I'm trying to do. Is there a nice way to code this up? Thanks.

\documentclass[margin=1cm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}[line width=1pt]
\shade[ball color = gray!40, opacity = 0.4] (0,0) circle (1.5cm);
\foreach \x in {1.5,2.1,2.7}
{\draw (0,0) circle (\x cm);}
\foreach \x in {1.8,2.4}
{\draw [dashed] (0,0) circle (\x cm);}
\draw [<->] (0,1.2) -- (0,1.7);
\end{tikzpicture}
\end{document}


Here is a "minimal damage" proposal.

\documentclass[margin=1cm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}[line width=1pt]
\shade[ball color = gray!40, opacity = 0.4] (0,0) circle (1.5cm);
\foreach \x in {1.5,2.1,2.7}
{\draw (0,0) circle (\x cm);}
\foreach \x in {1.8,2.4}
{\draw [dashed] (0,0) circle (\x cm);}
\foreach \X in {0,45,...,315}
{\draw [<->] (\X:1.2) -- (\X:1.7);}
\end{tikzpicture}
\end{document}