14 CFR §91.209

1. (a)During the period from sunset to sunrise (or, in Alaska, during the period a prominent unlighted object cannot be seen from a distance of 3 statute miles or the sun is more than 6 degrees below the horizon)—
   1. (1)Operate an aircraft unless it has lighted position lights;
   2. (2)Park or move an aircraft in, or in dangerous proximity to, a night flight operations area of an airport unless the aircraft—
      1. (i)Is clearly illuminated;
      2. (ii)Has lighted position lights; or
      3. (iii)is in an area that is marked by obstruction lights;
   3. (3)Anchor an aircraft unless the aircraft—
      1. (i)Has lighted anchor lights; or
      2. (ii)Is in an area where anchor lights are not required on vessels; or
2. (b)Operate an aircraft that is equipped with an anticollision light system, unless it has lighted anticollision lights. However, the anticollision lights need not be lighted when the pilot-in-command determines that, because of operating conditions, it would be in the interest of safety to turn the lights off.