I lived in Midtown Atlanta for several years and was lucky enough to have a great view of the skyline from my balcony. I got in to creating time-lapses of the sky as a hobby using first my Canon 7d and later my Canon 5d Mark III. For the time-lapse control I used an inexpensive Meike Timer Remote Control Shutter For Canon. They can be had for about $15-20 dollars.
PROTIP: I found that its best to keep your camera in manual mode so the exposure is not constantly changing as the time of day and lighting is changing in your shot. It's also a good idea to invest in a power cable for your camera so your batteries don't die in the middle of your amazing time-lapse.
This first video below was done with the Canon 5D mark III in HDR mode, the Canon 8-15mm L fisheye lens and adobe premiere
This time-lapse if from music midtown. It’s really cool to see the people move around in hordes too and from stages as bands start and stop. Created using Canon 7D and Tamron 17-50mm 2.8 lens
You can see in the video below I was on apeture priority mode. This caused exposure flickering as the clouds moved over the sun and the sun set behind the buildings.