  We use D1 gray molasses to achieve Bose-Einstein condensation of a large
number of $^{41}$K atoms in an optical dipole trap. By combining a new
configuration of compressed-MOT with D1 gray molasses, we obtain a cold sample
of $2.4\times10^9$ atoms with a temperature as low as 42 $\mu$K. After
magnetically transferring the atoms into the final glass cell, we perform a
two-stage evaporative cooling. A condensate with up to $1.2\times10^6$ atoms in
the lowest Zeeman state $|F=1,m_F=1\rangle$ is achieved in the optical dipole
trap. Furthermore, we observe two narrow Feshbach resonances in the lowest
hyperfine channel, which are in good agreement with theoretical predictions.
