Astronomy JavaScript

• SFA Moon Phases Calendar
• Planet Positions -- Additions
• Julian Day - calculation
• Heliocentric Julian Day - calculation
• Date & Time - updating time
• Jupiter Events - science calculations
• TimeZone - Offset and Daylight Saving Detector
• Slide Show
• JavaScript Drawing

 
The books by Muees and Duffett-Smith shown below can assist you with astronomical calculations such as Julian Day, Planetary Positions, etc. The Stars and Planets book is a good reference guide for use at the telescope.