The new show will open in the summer
The green-domed building in Marylebone Road, central London, opened more than 50 years ago but managers say it is failing to attract enough customers.
Diane Moon of the London Planetarium said the new London Auditorium would be transformed into a show which would "get into the heart of celebrity".
But well-known astronomer Sir Patrick Moore said the decision was "most regrettable".
"London must now be the only major city in the world without a planetarium.
"I have already had inquiries from people asking if they can't go to the London Planetarium, where can they go," Mr Moore said.
The London Auditorium is due to open in the summer.
London Planetarium

The London Planetarium, famous for its distinctive green dome and for being next to Madame Tussauds, will close this week to make way for a new celebrity-themed show opening in July. The Planetarium used to be an attraction in its own right, but in recent years has become simply a feature tacked onto the end of the waxworks tour, the original 45 minute show cut down to just over 10 minutes. The planetarium will be renamed 'The Auditorium' and will feature a show that "gets to the heart of celebrity", being produced in collaboration with animation house Aardman Productions.

Famous astronomer Sir Patrick Moore has called the decision "most regrettable", and many have commented that the change from space to celebrity is an unfortunate sign of our times.

To say 'farewell' to the planetarium, Tussauds have allowed free entry in its penultimate week, from 24th - 30th April. Visitors could enter through the group admissions entrance to see the show, running every twenty minutes. Unlike the queues for Madame Tussauds, which typically run right up the street, few people waited to see the planetarium show, even on the Saturday. The show, titled ''Journey to Infinity'', was projected onto the inside of the dome using Digistar 3 digital projectors. It told the story of space, starting from Earth and zooming out to reveal the other planets in the Solar System, the Milky Way, the other galaxies and the rest of the universe. It ended with an optimistic message suggesting that humans would continue to explore space, going further than ever before.

The London Planetarium opened in 1958 on the site of an old cinema that was destroyed in the second world war. Evening laser performances called 'Laserium' were held between 1977 and 1990. A £4.5 million redevelopment saw it relaunch in 1995 with a new 'Digistar II' monochromatic 3D projection system. This was upgraded to the full-colour 'Digistar 3' system in 2004 which is currently in use.

The planetarium at the also famous Royal Observatory in Greenwich has also been closed since September 2004, however this is due to re-open in 2007 having received a £15 million redevelopment programme. It will be three times the size of the old planetarium, and has received backing from Astronomer Royal Sir Martin Rees, and the Astronomer Royal for Scotland, Professor John Brown.