The ornamental design for a portableilluminator, as shown and described.
FIG. 1 is a perspective view of a portable illuminator showing my new design;
FIG. 2 is a front elevation thereof;
FIG. 3 is a rear elevation thereof;
FIG. 4 is a left side elevation thereof;
FIG. 5 is a right side elevation thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom view thereof, the broken lines in FIG. 7 are for illustrative purposes only and form no part of the claimed design; and,
FIG. 8 is showing another embodiment of a portable illuminator in a perspective view of the portable illuminator of FIG. 1 in an alternative position of use. The broken lines in FIG. 8 are for illustrative purposes only and form no part of the claimed design.