Graham,
The shield is made of H.I.P.S. High Impact Polystyrene Sheet.
It's light, flexible and very strong. You can use other materials, I've just found this works best for me.
I've lived in Campbelltown for 20 years. It's a great city, regardless what the politicans would like to do to it.
As with other cities, the night sky has deterioted. Our club meets at The Oaks to get a good dark sky, and at Berrima.
I've downloaded a few images to show how I've mounted the shield.
Since installation I haven't had one dew interupted night, it works very well.