Help me shop for a laptop? (See details.)

I’ve been a PC guy forever, but I have no qualms about getting a new MacBook Pro. In fact, I’m seriously considering it mostly because my life is on my iphone. But not married to it.

I want a 12–15 inch super high def screen (like the Retina display), ultra portable for travel, that has a battery life that will last all day—at least 8–9 hours, preferably more.

Currently I have a Lenovo brick that is my workhorse. I will keep that and use it mostly for astronomy, but it’s really heavy (T440), and its battery life is about 3–4 hours, which doesn’t fly.

So any ideas? Help me spend my money.