Using a telescoping handle with a broom or squeegee head can also work, but they may be less efficient at grabbing the snow. If you go with the roof rake, just make sure the head is made of a material that won't scratch the panel glass - plastic and foam are good, but you'll want to stay away from all types of metal. You might not be able to reach the highest parts of your array, but clearing the snow from the bottom will give the snow at the top a clear path to slide down. And don't sweat it if there is a bit of snow remaining on the panels when you've finished raking - the last bits will melt soon enough, and the panels don't need to be 100% clean to produce power.
I hope you found this helpful. And whatever you do, don't get on the roof with a shovel.