Answer: 0 seconds. There is no twilight on the Moon! The reason for this is that the Moon does not have any atmosphere. The reason there is something called twilight on Earth is because of light from the Sun that is refracted through the atmosphere. This is the reason why we see red sunsets (because near sunset, the blue light is scattered off dust in the atmosphere and only the red light reaches us), and blue skies (scattering of blue light off dust). In Moon, you will have a black sky and a bright Sun during day time. The Sun will set in the same manner as any star on Earth during night, and once the Sun sets, it will be night on the Moon. There will not be any twilight.
Jagadheep built a new receiver for the Arecibo radio telescope that works between 6 and 8 GHz. He studies 6.7 GHz methanol masers in our Galaxy. These masers occur at sites where massive stars are being born. He got his Ph.D from Cornell in January 2007 and was a postdoctoral fellow at the Max Planck Insitute for Radio Astronomy in Germany. After that, he worked at the Institute for Astronomy at the University of Hawaii as the Submillimeter Postdoctoral Fellow. Jagadheep is currently at the Indian Institute of Space Scence and Technology.