Thomas Jefferson Papers
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Thomas Jefferson’s Observations for Calculating the Latitude of Monticello, 30 January–4 February 1816

Observations for Calculating the Latitude of Monticello

1816. Jan. 30 Jan. 31. Feb. 3 Feb. 4.
Observed altitude
  error of instrumt
 68–28–30  68–56– 0  70–39–30  ☉’s
 true observd alt.      
 − refrn + parallax      
true alt. of ☉’s center      
☉’s decln Greenwich      
 − Monticello      
true height of Equator      
Zenith dist. = Lat.       
pocket sextant1  68–24–30.   68–23–30    70–39– 0 

MS (MHi); filed with TJ’s Weather Memorandum Book, 1802–16; written entirely in TJ’s hand on one side of a single sheet of paper, forming a grid with four rows and six columns.

1TJ repeated these headings in the second row, but he left the remainder of the last three rows blank.

Index Entries

  • astronomy; and calculations of Monticello’s latitude search
  • Jefferson, Thomas; Writings; Observations for Calculating the Latitude of Monticello search
  • latitude; calculations for Monticello search
  • Monticello (TJ’s estate); latitude of search
  • scientific instruments; sextants search
  • sextant; TJ uses search
  • sun; and calculation of latitude search