| late 1870s | Norman Lockyer began to assemble astronomical instruments in South Kensington … |
| 1881 | … which were then set up in temporary structures near the Post Office in Exhibition Road. Lockyer was appointed Lecturer in Astronomy at the Normal School of Science (NSS) just across the road. |
| 1885 | Lockyer became Professor of Astronomical Physics at NSS and Director of the Solar Physics Observatory (SPO). |
| 1901 | Sir Norman Lockyer (aged 65) retired from NSS. |
| 1909 | Lockyer started building a house later called Brownlands in Sidmouth. |
| 1912 | After forced closure of its Kensington site the SPO moved to Cambridge. Lockyer moved to Sidmouth. The Kensington and McClean telescopes were installed in new domes at the Hill Observatory. |
| 1920 | Death of Sir Norman Lockyer. His son, Dr.James Lockyer, took over as Director of what was to become the Norman Lockyer Observatory. |
| 1935 | Construction of Mond dome to house astrographic camera. |
| 1936 | Death of James Lockyer. Donald Edwards took over running of NLO. |
| 1948 | Exeter University took over responsibility for the NLO. |
| 1962 | Donald Barber, the last astronomer at NLO, retired. |
| 1974 | The newly-formed Sidmouth & District Astronomy Society (SIDDAS) was allowed occasional use of the buildings and instruments. |
| 1978 | Exeter University ceased geophysics work on the site. |
| 1984 | NLO site sold. Acquired by East Devon District Council. |
| 1985 | Sidmouth Amateur Radio Society (SARS) started to make use of the site. |
| 1987 | Sale of some NLO effects. |
| 1989 | The NLO was re-opened for EDDC by Patrick Moore. |
| 1989 | The McClean telescope was restored. The Mond dome re-opened as a small planetarium. A meeting room and a radio room were built onto the Mond dome. SIDDAS and SARS used the buildings under licence. |
| 1993 | The Lockyer and Browning telescopes were recovered and restored. |
| 1995 | The Norman Lockyer Society was formed from the amalgamation of SIDDAS and the SARS. The Observatory (NLO) was leased by East Devon District Council (EDDC) to the new Norman Lockyer Observatory Society (NLOS). |
| 1996 | An exhibition area, 60-seat planetarium and second radio room were built. |
| 1997 | Lockyer telescope installed in the Mond dome, replacing the planetarium projector. |
| 1999 | Victoria dome built and equipped with 12-inch Newtonian telescope. |
| 2004 | The SPO/NLO collection of historic photographic plates were recovered from the The Science Museum London. |
| 2005 | Spitz projector from Royal Observatory Greenwich was installed in the planetarium, replacing the original small instrument. |
| 2006 | 100-seat Donald Barber Lecture Theatre built. |
| 2007 | NLO library returned to NLO from Exeter University. |
| 2009 | McClean dome renovated and telescope brought back into use |
| 2010 | Lockyer telescope renovated. |
| 2011 | New Dome for 20 inch telescope is begun and Victoria dome renovated and new telescope donated for it. |
| 2012 | Connaght Dome and Lockyer Technology Centre opened by Dr Brian May. |
