Monthly Meeting 21 February 2024

Lagrange Points and Kordylewski Clouds

About the Talk

This talk introduces the concepts of potential, force and virtual force and shows how this applies to the circular, restricted three-body problem. The history and an overview of the theory and stability of Lagrange Points will be given, several Lagrange Points in the solar system are described and the use of Lagrange Points for observatory spacecraft, e.g. James Webb Space Telescope and Gaia, are explained as well as their use for spacecraft low energy transfer orbits.

Building on this, the talk moves on to describe the life of the Polish astronomer Kazimierz Kordylewski and the history of the elusive Kordylewski Clouds.

About this month’s speaker

Biography of Dr Paul A Daniels

BSc (Hons) Astrophysics, Queen Mary College, London

PhD, “Particle Accretion and the Structure and Evolution of Cometary Nuclei”, Sheffield

Worked on software for ROSAT (X-ray astronomy satellite) at the Max Planck Institut für Astrophysik, Garching (near Munich), Germany.

Worked for (now defunct) US company Floating Point Systems and then ICL Defence Systems and gained experience in high-performance computing.

Freelance IT consultant from 1988 for over 30 years – mainly database design and development

Allegedly retired since the start of 2019!

Joined Guildford Astronomical Society in 2006:

  • Joined the Committee in 2008
  • Became their Webmaster in 2009
  • Became Website and Meetings Organiser in 2011
  • Became President in 2012 up to 2018 when I moved to Norfolk.
  • Now an Honorary Member

(Re)Joined the RAS as a Fellow in 2009:

  • RAS Council member 2016-2019
  • RAS Vice-President (A) 2019-2021
  • Have served as Chair of IT Working Group and
  • on the Education and Outreach Committee
  • Still active on the Megaconstellation Working Group (Optical)

Joined FAS Council in 2016:

  • Became President in September 2017
  • Stepped down in 2023 but continuing as Interim President until a President is found


  • A member of the EAS and
  • A member of the IAU including the IAU CPS (Centre For The Protection Of The Dark And Quiet Sky From Satellite Constellation Interference).

Living near Bradenham in Norfolk since August 2018. Enjoying country life and walking the dog.



Anyone is welcome – beginner or expert – and there is no need to pre-book. A small charge applies to help us cover costs (typically £3 for non-members; £2 for NEAS members; U16s free). Doors open at 7.30pm with the talk starting at 8.00pm.

Note that if you are using satnav system, the postcode may not take you directly to the hall – please check this Google Maps link if you aren’t sure:



21 Feb 2024




Henry Dixon Hall
The Henry Dixon Hall, Henry Dixon Road, Rivenhall End, Essex, CM8 3HR