The Collaborative International Dictionary of English v.0.48:

Lucubrate \Lu"cu*brate\, v. i. [imp. & p. p. Lucubrated; p.
   pr. & vb. n. Lucubrated.] [L. lucubratus, p. p. of
   lucubrare to work by lamplight, fr. lux light. See Light,
   n.]
   To study by candlelight or a lamp; to study by night.
   [1913 Webster]