Encyclopedia
Discovery
- Famous astronomers
- Main dates
- Discoveries in
  the solar system
  - Sun
    - Sunspot
    - Solar eclipses
  - Mercury
    - Advance of the perihelion
  - Venus
    - Phases
    - Rotations
  - Earth
    - Form
    - Motion
  - Moon
    - Craters
    - Surface
  - Mars
  - Jupiter
  - Saturn
    - Rings
    - Satellites
  - Uranus
  - Neptune
  - Pluto
  - Asteroids
  - Comets
Space
- History
- Launching sites
- Space missions
  - Apollo
  - Mariner
  - Viking
  - Voyager
  - Galileo
  - Soho
  - Mars Express
  - Cassini/Huygens
  - Luna
Observatories
- FP7 ESPaCE Institutes
  - IMCCE
  - ROB
  - TUB
  - JIVE
  - CNES
  - DLR
  - TUD
- Other European observatories
  - Observatoire de Paris
  - Pic du Midi
  - OHP
  - Bordeaux
  - OCA
  - Besançon
  - Greenwich
  - Torino
  - Vatican
  - Catania
  - Bucarest
  - Pulkovo
  - SAI
- Institutes outside Europe
  - USNO
  - JPL
  - Mount Palomar
  - Zelenchuk
  - Shanghai
  - Itajuba
  - ESO
- The largest
  telescopes
  - Reflectors
  - Refractors
- Space observatories
  - HST
  - GAIA
  - SOHO
Understanding

Back to Easter date

Decrease font size

Increase font size

Print this page

Understanding > Fundamental concepts> Perpetual lunar calendars

Perpetual lunar calendars

julian and gregorian

Credit : J. Lévy/Annuaire du Bureau des longitudes