The ornamental design for a moonphotography prop, as shown and described.
FIG. 1 is a perspective view of a moon photography prop, showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines in the drawing views are included for the purpose of illustrating portions of the moon photography prop that form no part of the claimed design.