4 a.m.

[Mark A Becker]

Half-moon horizon
bowl of light
tipped over in the haze,
4 a.m. again.

Hmm... Trust me, I do agonize over these short ones...

Half-moon horizon "horizon" is too close to "half moon" to have the right effect
bowl of light  I like this image, but... 
tipped over in the haze, something about this line just doesn't feel right
4 a.m. again. the more I think about it, the more I think that a comma is needed after 4am. I don't think you need the periods after am (a.m.).  Though they're gramatically correct, I think they interfere. My reasoning for that comma is to show that this "observation" recurs.

My latest stab at it:

waning moon spills light
on a hazy horizon-
4am, again

I understand what yer going for, and working these short ones is a killer.  I took the liberty to offer "waning moon" instead of "half moon" because I just thought it fit better.  And folks tend to visualize the shape of a waning moon without being told. Even though it was a half-moon you were observing, it won't be half for long, and half-to-quarter is waning. "Waning" and "spills" may also fit the subject better, and "waning" picks up an internal rhyme with "hazy". I dunno... 
My only other suggestion would have been "bowl-like moon pours light", but it's just something about the word "bowl" that conjures the wrong image (could just be me, as usual).

For someone who eschews such tight structure, I am impressed that you're sticking with this.  It's a bitch, ain't it?

Mark