This is an Auto Bulb Ramp with the Timelapse+ using both aperture and ISO stepping in conjunction with the bulb ramping. After dark I used the manual ramp rate override to ramp up about 2 stops over 30 minutes (since it seemed a little dark), bringing the overall span of the time-lapse to about 18.5 stops from start to finish. It ran from 7pm to 1am, with the sun setting around 9pm and moon rising a little after 11pm.
I set the Aperture Min and Aperture Max to a little above and below the limits of the lens, since the vignetting is most severe at the limits. Using the aperture during a time-lapse still causes flicker, but with the limits it's at least pretty even across the frame allowing for pretty decent correction in post (with LRTimelapse).
The starting exposure was 1/20s, ISO 50, f/18 and the final exposure was 18s, ISO 2500, f/4. The interval was set to 20 seconds and the integration time was 15 minutes.
It was taken from my roof again, and to my surprise (and delight) the sky was the clearest I've seen from this location. You can actually make out the Milky Way!
Made with the Timelapse+