About In-The-Sky.org

In-The-Sky.org is an online guide to what you can see in the night sky, which automatically tailors its information to wherever you happen to live.

Founded by Dominic Ford in 2012, it has grown to cover planets, asteroids, comets, deep sky objects, as well as satellites in low Earth orbit.

How it works

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.

Dominic Ford

Dominic Ford

Dominic Ford is a postdoctoral researcher at Lund Observatory in Sweden. I am the lead software engineer on the data analysis pipeline for the Milky Way surveys that the 4MOST multi-object spectrograph will carry out.

I have a particular interest in machine-learning techniques for analysing astronomical spectra, which may be the only feasible way to process the tens of thousands of spectra that 4MOST will observe every night.

Prior to moving to Sweden, I worked as a freelance science communicator in Cambridge, UK. I run many websites, including:

  • ScienceDemos.org.uk – a collection of interactive science demos.
  • HillTopViews.org.uk – a three-dimensional terrain map of the world, based on altitude data collected by NASA's Shuttle Radar Topography Mission (SRTM) in 2000.
  • Pyxplot – A graphing and vector graphics package which I wrote in 2008–2012. It is available in the Ubuntu package archive.
  • Dominic's photos – When I'm not doing other things, I dabble in amateur photography, and you can find some of my photos here.

Some of my other projects include:

  • The Observer's Guide to Planetary Motion – My book, which describes much of the science behind how In-The-Sky.org does its calculations.
  • MeteorPi – a fun project which ran from 2014–2016 in collaboration with Cambridge Science Centre. I was the lead developer for a network of motion-sensitive security cameras which we set up to triangulate the three-dimensional trajectories of shooting stars, satellites and aircraft. We used Raspberry Pis to do the real-time image analysis, running astrometry.net to precisely determine the direction each camera was pointing, and a GPS receiver to determine their positions. This project is currently dormant, but I'd like to restart it one day. The code needs a lot of cleaning up, but is all available on GitHub.

Going back in time, some projects I worked on long ago include:

  • GrepNova – an automated image-comparison tool for amateur astronomers who hunt for supernova. This tool was used by Tom Boles, who currently holds the world record for the largest number of supernovae discovered by any single individual.
  • Naked Astronomy – Between 2012 and 2014 I worked for the Naked Scientists in Cambridge, where I produced the STFC-funded podcast Naked Astronomy. I also spent one day a week in the newsroom of BBC Radio Cambridgeshire, acting as a science advisor.
  • Square Kilometre Array – Between 2007 and 2012, I worked as a postdoctoral researcher at the Cavendish Laboratory, Cambridge, investigating how easy it would be to use Graphics Processing Units (GPUs) to build a correlator for the SKA. In short, GPUs are a complete pain to use!
  • PhD Thesis – I was awarded my PhD from the University of Cambridge in 2008, where my supervisor was Prof Paul Alexander. Paul and I built a model of the infrared spectra of dusty star-forming galaxies, which were being observed in large numbers at that time by Spitzer. My thesis title was A Semi-Empirical Model of the Spectra of Dusty Galaxies.

Going even further back in time, in the 1990s I was the kind of geeky teenager who sat in my bedroom writing computer games for my Acorn Electron. I even got a couple of them published, though the reviewers spotted, quite correctly, that I wasn't very good at making up story lines.

  • Shipwrecked – Published here and reviewed in detail here. In the unlikely event you want to try and complete it, you may find this solution useful. It even got ported to the Commodore 64!
  • Jupiter III – The sequel to Shipwrecked, published here and reviewed in detail here. This was my first attempt at high-speed scrolling graphics. In the unlikely event you want to try and complete it, you may find this solution useful.

All of the information and diagrams on this website are © Dominic Ford.

However, they are provided for the benefit of amateur astronomers worldwide, and you are welcome to modify and/or redistribute any of the material on this website, under the following conditions:

  1. Any item that has an associated copyright text must include that unmodified text in your redistributed version,
  2. You must credit me, Dominic Ford, as the original author and copyright holder,
  3. You may not derive any profit from your reproduction of material on this website, unless you are a registered charity whose express aim is the advancement of astronomical science, or you have the written permission of the author.

Contact details

You can email me at root@




Color scheme