A marker assembly for locating a handheld implement, the marker assembly comprising: a support member connectable to a longitudinal shaft of the handheld implement, said support member comprising: a pair of proximal segments configured to extend from said longitudinal shaft when said support member is connected to the longitudinal shaft and at least one distal segment extending from said proximal segments, wherein said proximal segments and said at least one distal segment at least partially surround a central aperture; wherein said pair of proximal segments form a proximal plane and said one or more distal segments form a distal marker plane, wherein said distal marker plane is angled, relative to said proximal plane, toward a distal region of said handheld implement one or more tracking markers affixed to said at least one distal segment; and wherein said distal marker plane is not parallel to the longitudinal axis of the longitudinal shaft when said marker assembly is secured to the handheld implement; wherein said one or more tracking markers are suitable for locating a three-dimensional position and orientation of said handheld implement when said marker assembly is secured to said handheld implement; and wherein said proximal segments and said at least one distal segments form said central aperture such that, when said marker assembly is secured to said handheld implement and during use of said handheld implement, a clear view of a distal end of the longitudinal shaft is provided through the aperture. a support member connectable to a longitudinal shaft of the handheld implement, said support member comprising: a pair of proximal segments configured to extend from said longitudinal shaft when said support member is connected to the longitudinal shaft and at least one distal segment extending from said proximal segments, wherein said proximal segments and said at least one distal segment at least partially surround a central aperture; wherein said pair of proximal segments form a proximal plane and said one or more distal segments form a distal marker plane, wherein said distal marker plane is angled, relative to said proximal plane, toward a distal region of said handheld implement one or more tracking markers affixed to said at least one distal segment; and wherein said distal marker plane is not parallel to the longitudinal axis of the longitudinal shaft when said marker assembly is secured to the handheld implement; a pair of proximal segments configured to extend from said longitudinal shaft when said support member is connected to the longitudinal shaft and at least one distal segment extending from said proximal segments, wherein said proximal segments and said at least one distal segment at least partially surround a central aperture; wherein said pair of proximal segments form a proximal plane and said one or more distal segments form a distal marker plane, wherein said distal marker plane is angled, relative to said proximal plane, toward a distal region of said handheld implement one or more tracking markers affixed to said at least one distal segment; and wherein said distal marker plane is not parallel to the longitudinal axis of the longitudinal shaft when said marker assembly is secured to the handheld implement; wherein said one or more tracking markers are suitable for locating a three-dimensional position and orientation of said handheld implement when said marker assembly is secured to said handheld implement; and wherein said proximal segments and said at least one distal segments form said central aperture such that, when said marker assembly is secured to said handheld implement and during use of said handheld implement, a clear view of a distal end of the longitudinal shaft is provided through the aperture.