HENDERSON, THOMAS, professor of practical astronomy, Edinburgh. - This distinguished astronomer was born in Dundee, Dec. 28, 1798. His father, who was a respectable merchant,after giving the best education they could provide to his hometown, Thomas apprentice at the age of fifteen years, Mr. Small, a writer or a lawyer, whose office his brother then was a partner. Here heserved a term of six years with great diligence, and in the end of that period removed to Edinburgh, to perfect himself in the study of law as his future profession. Having had a situation where awriter's Office for the label, skill and diligence attracted the attention of Sir James Gibson Craig, by whose recommendation he was appointed Secretary or Secretary of attorney to the talented andeccentric John Clerk, later elevated to the bench under the title of Lord Eldin. Upon retirement of the latter to private life, Mr. Henderson obtained the situation of private secretary to the Earl ofLauderdale, who later left the more lucrative appointment as Secretary to Francis Jeffrey, then Lord Advocate, in which office he continued until 1831.
DISCOVERY OF THOMAS HERDENSON
Henderson waspassed over for that position, but the recommendation was enough to get him a position at the Royal Observatory at the Cape of Good Hope in South Africa. There he made a considerable number of stellarobservations between April 1832 and May 1833, including those for which he is remembered today. It was pointed out to him that the bright southern star Alpha Centauri had a large proper motion, andHenderson concluded that it might be a close star.
The 1830s version of the "space race" was to be the first person to measure the distance to a star using parallax, a task which is easier the closer thestar. Henderson was thus in a good position to be this person. After retiring back to the United Kingdom due to bad health, he began analysing his measurements and eventually came to the conclusion...