Out of Space

Does Earth have a natural prime meridian?

Duncan Steel Mar 20, 2019

We are generally habituated to using the Greenwich meridian as the global standard for mapping and time-keeping, despite it being only 135 years since its adoption. As I show here, if the Catholic Church had adopted in 1582 a more-precise calendar in terms of year length then a natural prime meridian results, in a location that might appear surprising. Read More

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On the Shoulders of Giants?

Duncan Steel Mar 16, 2019

Isaac Newton is often thought to be the inventor of the apparently self-deprecating phrase ‘If I have seen further it is by standing on the shoulders of giants’, but he was not: actually it had been in use for over 500 years before he repeated it in 1675. Of more significance is that Newton wrote it in a letter to … Read More

New Zealand from Space

Duncan Steel Mar 11, 2019

The European Space Agency’s current Earth observation image of the week features New Zealand in all its glory. Let us take it as read that NZ is a beautiful, breathtaking country. Myriad artistic renditions and simple tourist snaps bear witness to that, but it is also truly an amazing sight when seen from high above, by satellites in orbit. Read More

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Space Station and docked Dragon capsule visible throughout NZ

Duncan Steel Mar 04, 2019

As I write, the Dragon capsule – a spacecraft intended to loft US astronauts into orbit – has been docked with the Space Station for almost 18 hours on its initial test flight. It happens that you will be able to see the station plus capsule passing over New Zealand each evening for the next week or so, before the … Read More

Times to Spot the Space Station

Duncan Steel Feb 19, 2019

It’s easy to see the International Space Station passing overhead: you just need to know when and where to look. Oh, and a clear sky. The International Space Station (ISS) regularly passes across New Zealand, a little more than 400 km above our heads – rather less than the distance between Auckland and Wellington. Most of these transits … Read More

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The Nelson bush fire: What can satellite images tell us about such events?

Duncan Steel Feb 12, 2019

The ongoing fires in the Nelson-Tasman region have quite rightly provoked much alarm. The response of Fire and Emergency New Zealand, the NZ Police, the NZ Defence Force, and many private individuals, has been magnificent. However, the utilisation of satellite imagery for assessing such fires and then planning and responding is deficient in NZ compared to much of the rest … Read More

Satellite imagery of the Nelson bush fire

Duncan Steel Feb 09, 2019

The area burnt in the ongoing bush fire in the Nelson-Tasman region, largely around Pigeon Valley near Wakefield, can easily be seen in satellite imagery collected in recent days.  Earth observation satellites frequently cross New Zealand and, clouds allowing, collect imagery of the land and sea below. In later posts I will discuss such data collection in more detail, but … Read More

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Satellite Orbits: Global Navigation Systems

Duncan Steel Feb 05, 2019

Apart from the US-provided Global Positioning System (GPS) used by most commercial navigation systems – such as in your car, or mobile phone – there are several distinct networks operated by other space agencies deploying their own satellite fleets. Here I describe the orbits employed by the Russian, European Union and Chinese GNSS constellations. (Part 3 in a series of … Read More

Harry Hindmarsh Atkinson: obituary

Duncan Steel Jan 27, 2019

Harry Atkinson in 2012 (courtesy William Tobin). Harry Atkinson was one of those able New Zealanders who went overseas to study, fully intending to return one day to these shores to live, but due to their great success in their adopted homelands never did so. A physicist by training, he moved into science advice and administration in Britain and … Read More