In The Sky

In-The-Sky.org needs to know where you live to work out what you can see in the night sky. By default, it traces where your internet connection is coming from, but sometimes this doesn't work out. If you want to manually specify where you live, then click here. Once we've got your location, we need to calculate where objects will appear in your sky... . Most of our planetary predictions are derived from the DE405 ephemeris, which is produced by NASA's Jet Propulsion Laboratory (JPL) in California. NASA use this to guide their space missions to their intended destinations, so it's astonishingly accurate - it typically lists the positions of the planets to an accuracy of a few kilometers. To list the eclipses, conjunctions, oppositions, and other such alignments that you'll be able to see, we do an automated search of DE405 for events which seem favourable. Much of the text you'll see on In-The-Sky.org is automatically generated specifically for you, based on exactly where in the sky each event will appear. The positions of asteroids are calculated from orbital elements published by Ted Bowell of the Lowell Observatory. Orbital elements for comets are taken from the Minor Planet Center (MPC). Comet magnitudes are calculated on the basis of observations sent into the BAA Comet Section, as compiled by Jonathan Shanklin and Nick James. The positions and brightnesses of deep sky objects are taken from a wide variety of catalogues. Much of the science behind how In-The-Sky.org does its calculations is described in the author's book, The Observer's Guide to Planetary Motion , published by Springer.Read More