Hi r/photography! I've browsed the links on the sidebar for a bit, but really am looking for some personal/specific advice on getting into the DSLR business. Any help ya'll could provide would be fantastic. Hopefully ya'll don't mind long-winded posts...

I started doing astronomy research a few years back, and after actually getting to travel to Mauna Kea, Hawaii and see the stars at night and the vistas during the day, I realized my old Canon pocket camera I'd been using for years just wasn't going to cut it.

I was too poor at the time to even think of a DSLR, so I invested in a used Panasonic Lumix ZS6 which has provided the ability to do some longer exposures of stars/telescopes (telescope in full moonlight, telescope with galactic center on a moonless night, lava crater), wildlife in the grand canyon (squirrel, raven), and some scenery (sequoia national park).

Though I clearly haven't mastered the camera I have, I feel stifled a bit by it, especially trying to shoot night scenes. I'm planning a road trip this fall to see ten different national parks in the western US and am strongly considering an upgrade to my camera capabilities. So I have a few questions about what my best options are given my budget and target shots. Though no camera is going to make me a better photographer, I figure having the right tools might at least make it easier for me to learn (could be wrong, though).

As far as what I'd like to be equipped to get good shots of:

1) Landscapes 2) Wildlife 3) Starscapes

My budget is probably only $400-$600 total at the moment, though I might be convinced to go higher if the cost/benefit analysis is right. As I've been browsing through recommended lists of cameras/lenses for beginners, I'm left with a lot of questions:

1) What really is the best camera body for me?

2) Should I invest in a model with weatherproofing of some kind - is it even possible on a reasonably priced model?

3) External triggers - right now I simply set a delay on the camera to eliminate initial shake when I take night shots, but I figure some sort of wireless trigger would be even better.

4) What lenses should I buy to start with? Will the "standard" 18-55mm lens that seems to come with most body kits be sufficient for what I'm interested in? What would be the ideal backup lens?

5) Should I buy refurbished?

6) Is it possible to get a much older body (say 4 years) that is going to be significantly cheaper than a newer model but I won't notice a difference given my (minimal) photography abilities, or again, is it really worth the extra money to get the semi-latest tech?

I'm excited about the possibilities, but I feel lost in the sea!

Thanks everyone!