I'm been starting to do a bit of astro photography and would love to get into it a bit more. I have a 5D MKIII, so I'm all set from a body point of view. The best low light lens I possess is Canon 50mm 1.8, but obviously this is no good for wide angle shots. I've been eyeing up the Canon EF 16-35mm f/2.8L II, but the price is putting me off a bit. I'll take the plunge if I have to, but as I'm starting out in this area of photography, I'd rather spend a little less whilst I find my feet.I'm mainly interested in capturing the Milk Way in different landscape scenarios and star trails. Can anyone suggest any kit that may be appropriate for what I'm aiming for? Thanks.