Does the angle of the moon's crescent change with respect to the horizon through the night?
Yes, the direction that the moon's crescent appears to point different directions during the day because it always points towards the sun. I've attached two planetarium program pictures to show you the way a crescent moon might look at sunset and then sometime later when it is about to set.
Everett's research focus is extra-solar planets or exoplanets. These are the planets far, far beyond Neptune and Pluto, which orbit other star systems. He observers exoplanet atmospheres to learn about their composition. The colors of an absorbing exoplanet atmosphere tell astronomers what the atmosphere is made of, so he uses spectrographs to split up the colors of these star-planet systems and infer which gases make up its atmosphere. He also is building a new infrared spectrograph to go on the Blanco Telescope in Chile with the TripleSpec 4 team.