On being appointed to fill a vacancy at the Royal Observatory he was immediately involved with a research project which had been underway since 1900 when photographic plates of Eros had been taken over the period of a year. Eddington's first task was to complete the reduction of these photographic observations to determine an accurate value for the solar parallax.
Sa pagiging hinirang upang punuan ang isang bakanteng sa Royal obserbatoryo siya ay agad-agad na kasangkot sa isang proyektong pananaliksik na had been underway mula noong 1900 kung kailan Photographic plates ng seks had been taken sa paglipas ng panahon ng isang taon. Eddington ang unang gawain ay upang makumpleto ang pagbabawas ng mga Photographic mga obserbasyon upang matukoy ang isang tumpak na halaga para sa solar paralaks.