Mary Parsons, Countess of Rosse (née Field; 14 April 1813 – 1885), was an Anglo-Irish amateur astronomer, architect, furniture designer, and pioneering photographer.

She had a sister, Delia, and they were educated at home by Susan Lawson, a governess who encouraged the young Mary's creativity and broad interests, including astronomy.

[3] The Leviathan of Parsontown was completed in 1845 and held the record as the world's largest telescope for over 70 years, and was mentioned in Jules Verne’s science fiction novel, From the Earth to the Moon.

[3] She created a huge dining room at Birr Castle in which to entertain scientific guests, which became increasingly used when Lord Rosse became President of the Royal Society of London in 1848.

She recorded the Leviathan in her photographs including one image showing her three sons, Clere, Randal, Charles and her sister in law, Jane Knox, standing upright at the mouth of the telescope.