M639

ALTERNATE NAME/NUMBER - Mile 639

75º 42' 41" S

125º 37' 53" W

1690 Meters

BYRD STATION TRAVERSE

1959-60 Season

Engineer: William H. Chapman

Solar position at Mile 639 is the horizontal datum used to determine the horizontal positions of the intersected map control points on Mount Galla.

Elevations determined by altimeter traverse based on Byrd Station elevation of 1530 meters.

Wild T-2 used for angular measurements.

Located approximately 25 km NE. Mount Galla.

Station mark - unmonumented snow station.

Surveyed 1959-60.

Horizontal Datum - Position based on the Astronomic Position of M639.

Vertical Datum - Mean sea level.

BYRD STATION 1959-1960 TRAVERSE

Traverse starts and ends at Byrd Station elevation 1530. Stations spaced 3 nautical miles apart to Mile 998, then 5 statue miles to Byrd Station. Stations designated by numbers from Mile 0 to Mile 998 represent the number of nautical miles traveled from Byrd Station. From Mile 998 to Byrd Station, the stations are designated by numbers given by the Army-Navy Drive Traverse. Mile 390.5 is a tie to sea-level by triangulation on water-line of icebergs. Miles 258, 603, 711.5, and 890 are tied to the Marie Byrd Land Electronic Traverse of 1966-67-68 field seasons. The Marie Byrd Land Electronic Traverse was tied to sea-level by triangulation from the Alexander Mountains in the Edward VII Peninsula area, Grant Island on the western end of the Getz Ice Shelf and Wright Island on the eastern end of the Getz Ice Shelf. The altimeter elevations have been adjusted to agree with the elevations determined from the electronic traverse at the above stated points.