Algernon Charles Gifford was born on board the Zealandia on Good Friday, 18 April 1862, somewhere off the Cape of Good Hope. He was the son of Sarah Annie Evans and her husband, Algernon Gifford, an Anglican clergyman who was en route to his new parish of Waitaki, New Zealand. Upon arriving the family settled in Oamaru, where the young Gifford attended Oamaru Grammar School.
In 1876 he was sent to England to further his education. He attended a church school at Denstone, Staffordshire, for four years before accepting a sizarship to St John's College, Cambridge. There he obtained an MA in mathematics, graduating fourteenth wrangler in 1880 and winning the Herschel Prize in astronomical mathematics. He also represented the college in rugby.
After returning to New Zealand, Gifford obtained teaching posts in science and mathematics at Waitaki High School (1883–89), and then at Christ's College, Christchurch (1889–92). While there he was influenced by the charismatic Alexander Bickerton, professor of chemistry and physics at Canterbury College, who was actively promoting his 'partial impact' theories to explain novae and the formation of the solar system and even spiral galaxies. Subsequently, Gifford was to spend a good deal of research effort trying to prove Bickerton's theories, in the process publishing a number of research and review papers in the local journal Southern Stars and the international journal Scientia. He also produced a 22-page booklet about Bickerton's theories, written especially for a lay audience.
From 1895 to 1927 he taught at Wellington College, where he became head of the science department, and was acting principal for a period. On 8 May 1901 at Oamaru, Gifford married Susie Jones. They were to have three children.
A large, bearded man with a 'perpetual twinkle about the eyes', Gifford was a talented and popular teacher and was known affectionately to more than a generation of boys as 'Uncle Charlie'. His enthusiasm for astronomy was contagious. He was responsible in 1911 for establishing Wellington College's observatory, which when completed in 1913 housed a fine 5⅛-inch equatorially mounted Zeiss refractor, used by many pupils over the years for serious astronomical observation. A number of these pupils later went on to achieve national prominence in amateur and professional astronomy circles.
Gifford took his astronomy to the wider public through his weekly articles in the Evening Post, Wellington, during the 1920s and 1930s. These were subsequently reprinted in booklet form as In starry skies, appearing in 14 separate volumes. At the time they collectively formed an excellent introductory textbook on astronomy. Part of their appeal was the occasional reference to New Zealand astronomy and astronomical history.
Gifford was a skilled public lecturer: he could fill the largest halls in Wellington and keep his audience enthralled for two hours or more. In 1934 he presented a Donovan Lecture in Wellington, sponsored by an Australian astronomical bequest, becoming one of very few New Zealanders accorded this honour.
One of Gifford's more unusual astronomical forays was his grandiose plan to construct a 'People's Observatory', and in 1930 he initiated a popular astronomical society known as the Students of the Starry Skies. The immediate aim was to install a 40-inch telescope in Central Otago through funds raised by the society. Gifford actively promoted the society in his Evening Post articles, and the inaugural meeting was held in Wellington in March 1930. By June there were 600 members throughout New Zealand, and branches had been formed at a number of schools. Regrettably, the depression intervened.
Although primarily a theoretician and a populariser, Gifford did own a telescope – a four-inch refractor – which was housed in a small roll-off roof observatory on his property at Silverstream, near Wellington. He was a fellow of the Royal Astronomical Society, London, and a member of astronomical societies in Britain, France, Canada and the Pacific. He was president of the Royal Astronomical Society of New Zealand and a leading member of the Wellington Philosophical Society, serving as president and secretary. For a time he was also an associate of the Dominion Observatory in Wellington.
Late in life Gifford turned his attention to unorthodox astronomical theories, publishing research papers on gravitation and a theory of radiation. While many of his conclusions are no longer accepted, Gifford did make an important international contribution to lunar astronomy. In 1924 and 1930 he published two hallmark papers in the New Zealand Journal of Science and Technology in which he was able to demonstrate mathematically that meteoric impacts were responsible for the formation of lunar craters. Until this time astronomers had believed they were caused by volcanic activity. In 1987 the American astronomer W. G. Hoyt was to pay a major tribute to Gifford in his book Coon Mountain controversies: meteor crater and the development of impact theory.
In addition to his astronomy, Gifford took a keen interest in gardening, field geology, the authorship of works usually attributed to Shakespeare, and contemporary economics.
Gifford died in his home at Silverstream on 27 February 1948. He was survived by his wife, Susie, two sons and a daughter. After his death the funds of Students of the Starry Skies passed to the Carter Observatory and were used to purchase telescopes for schools. His important contribution to New Zealand astronomy is commemorated by the Gifford Fund of the Royal Astronomical Society of New Zealand, which is used to finance lectures to regional astronomical societies by notable New Zealand and overseas astronomers.