Summiting on or soon after a full moon is very beautiful and helps illuminate the landscape without using headlamps. However, it is also very bright for sleeping and stars are not as visible.
To summit on a full moon, you will want to start a 6-day trek 4 days before the full moon (3 days before if doing a 5-day trek).
NEW MOON (Kili under the stars)
* Partial Lunar Eclipse (July 17, 2019)
** Super Full Moon (January 2, 2018; January 21, 2019; February 19, 2019; March 9, 2020; and April 8, 2020) (full moon at its perigee, or closest point of its orbit to Earth, where it will look bigger than normal)
*** Total Lunar Eclipse (July 27, 2018)