Stetson line of position plotter
Date: circa 1928
Inventory Number: 1996-1-0054
Classification: Plotting device
Subject:
Maker: Eastern Science Supply Company (fl. 1910s - 1940s)
Inventor: Harlan True Stetson (1885-1964)
Cultural Region:
Place of Origin:
Dimensions:
31.8 × 39.5 × 3.3 cm (12 1/2 × 15 9/16 × 1 5/16 in.)
Accessories: instructional material, in CHSI instrument file 2001-1-0024
Description:
Aluminum plotting table, painted black.
The surface of the plotting table is etched with a diagonal grid. Visible through a slit in this strip is an aluminum cylinder printed with sixteen scales. The cylinder is rotated by turning a black knurled knob at the top edge of the plane table.
There are four metal clips along the top and bottom edges of the drafting table. Also visible along the top and bottom edges are metal bolts joining the surface and sides of the table.
Two metal plaques bolted to one side of the drafting table are printed with information on the plane table's manufacturer.
The plotting table opens to reveal a space for storage.
The surface of the plotting table is etched with a diagonal grid. Visible through a slit in this strip is an aluminum cylinder printed with sixteen scales. The cylinder is rotated by turning a black knurled knob at the top edge of the plane table.
There are four metal clips along the top and bottom edges of the drafting table. Also visible along the top and bottom edges are metal bolts joining the surface and sides of the table.
Two metal plaques bolted to one side of the drafting table are printed with information on the plane table's manufacturer.
The plotting table opens to reveal a space for storage.
Signedprinted on leftmost plaque bolted to side of table: MADE BY / EASTERN SCIENCE / SUPPLY COMPANY / P.O. BOX 1414 / BOSTON, MASS., U.S.A.;
printed on long bar of each T-square, right center: Manufactured by Eastern Science Supply Company, Boston, Mass.
printed on long bar of each T-square, right center: Manufactured by Eastern Science Supply Company, Boston, Mass.
Inscribedprinted on rightmost plaque bolted to side of table: PATENT APPLIED FOR
FunctionFor use in nautical astronomy, to lay out lines of position.
The user first secures a piece of plotting paper in the plotting table's four clips. He rotates the knob at the top left of the table until the latitude scale of his choice is shown. Similarly, he looks to the T-square for his line of longitude.
After plotting a point, he places a celluloid line locator over the plotting paper such that one line passes through the center of the compass protractor (printed on paper) in the direction of the sun's bearing. He moves the locator along this line until he can draw the line of position through the point along the short edge of the locator.
The user first secures a piece of plotting paper in the plotting table's four clips. He rotates the knob at the top left of the table until the latitude scale of his choice is shown. Similarly, he looks to the T-square for his line of longitude.
After plotting a point, he places a celluloid line locator over the plotting paper such that one line passes through the center of the compass protractor (printed on paper) in the direction of the sun's bearing. He moves the locator along this line until he can draw the line of position through the point along the short edge of the locator.
Curatorial RemarksUnlike nearly identical instrument 2001-1-0024, this one does not include T-squares or translucent celluloid panels.
See also two other Stetson line of position plotters, 1996-1-0055, 2001-1-0024.
Table wrapped in styrofoam padding.
See also two other Stetson line of position plotters, 1996-1-0055, 2001-1-0024.
Table wrapped in styrofoam padding.
Primary SourcesSee this abstract in Popular Astronomy for H. T. Stetson's description of the instrument's use.
