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OpenLearn Live: 30th August 2016

Updated Tuesday, 30th August 2016

He made reflecting telescopes, and he made them well. Meet James Short. Then more free learning across the day.

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OpenLearn Live brings the world of learning and research into your world. This page will be updated across the day.

On Friday, we completed a week of bolts, connected to the internet of everything and explored ways to trust online video

See the complete collection of OpenLearn Live

Today's posts

Chasing rainbows

There's potentially more waiting for us at the end of the raindow than just some pots of gold. Alexander Haußmann, writing in the European Journal Of Physics, suggests that it's time to study rainbows a little more seriously:

It is regrettable that the rainbow, like other atmospheric effects, is often covered only very briefly at all education levels from primary school to university. It is thus a further goal of this review to promote rainbows as apt examples not only for reflection and refraction on and in water spheres, but also for more advanced optical effects such as interference and multiple scattering. No expensive equipment is needed for these observations—an ordinary camera, and optionally a polarizer, are fully sufficient. However, natural rainbows do not occur too frequently (typically 10–20 days per year in Germany, or 40–70 days in the English Midland), but luckily it is possible to study rainbow scattering using artificial drop sources without great expense.

Read the full paper: Rainbows in nature: recent advances in observation and theory

From OpenLearn: The rainbow analysed

Life expectancy after the Arab Spring

The turmoil which followed the Arab Spring - and most notably, the conflicts which unfolded following the initial pro-democracy moments - has taken its toll on the people. The Lancet has conducted a survey into the health of people in the region, and it's pretty grim:

Our study shows that the eastern Mediterranean region is going through a crucial health phase. The Arab uprisings and the wars that followed, coupled with ageing and population growth, will have a major impact on the region's health and resources. The region has historically seen improvements in life expectancy and other health indicators, even under stress. However, the current situation will cause deteriorating health conditions for many countries and for many years and will have an impact on the region and the rest of the world. Based on our findings, we call for increased investment in health in the region in addition to reducing the conflicts.

Syrian men now have a life expectancy five years shorter than if the crisis in their country hadn't happen; in the first decade of this century infant death rates in Syria had been falling at a rate of over 6% a year; since 2010 that's more than reversed and the infant death rate is now rising at nearly 10%.

Read at The Lancet [subscription required]: Health in times of uncertainty in the eastern Mediterranean region, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013

Read at LSHTM: Expert commentary on the report

Read at OpenLearn: Why Syrian medics are setting up hospitals in caves

On iPlayer now: More Or Less

Catch up with the latest More Or Less on iPlayer - this weekend's edition covered the gap in pay between genders, the spread of death penalty abolitionism, Jeremy Corbyn, and the price of hospitals.

Listen to More Or Less online

Find out more about More Or Less

Tech news Tuesday

There's such an extraordinary amount of news around today relating to tech news that we've spun it all off into a separate reading list, where you can catch up on Corbyn's proposals, Apple's taxes, Facebook's privacy and algorithm problems and more.

Explore the reading list

Short people: James Short

This week, it's a short week, and to mark this short week, we're going to celebrate the lives of some people called Short with short biogrpahies.

We're going to start with James Short, the Scottish mathematician and optician. He was the first person to build a functioning reflecting telescope.

Gregorian, alt-azimuth mounting telescope. With brass plated telescope and mounting, three legged. Spirit level attached to top of scope. Signed James Short. Creative commons image Icon Birmingham Museums Trust under Creative Commons BY-SA 4.0 license A telescope built by James Short held in the Birmingham ThinkTank museum

James was born in Edinburgh in 1710, attending his local university with the original intention of joining the church. His plans, though, were changed after being inspired by Colin Maclaurin's lectures on optics. Maclaurin encouraged him by offering him space and equipment to experiment, helping James refine his technique and understanding of telescopy to the point where he was able to better John Hadley's method of making the parabolic mirrors needed by reflecting telescopes.

Short made over 1,250 mirrors for telescopes during his thirty year career. So good was he at making these devices, he was a proud specialist. Writing in the Science Museum Group Journal, Jim Bennett explains just how unusual that was for the time:

A public avowal of that degree of specialism in the instrument trade was very unusual in eighteenth-century London. Makers who offered their wares in shops supplying retail customers were more inclined to maximise their apparent range, even though there surely were very specialised workmen either in the workshop behind the shop or, more likely, in the workshop of a subcontractor supplying parts or processes. Yet it was usual to give customers the impression of a business boasting a wide range of instruments.

So good were his devices that it was a Short telescope which accompanied Captain Cook on his mission to view the Transit of Venus.

When Short died in 1768, he had his tools destroyed. He'd always been secretive about his work; he was determined that his methods would die with him.

His telescopes, though, survive - including one held by the Wipple Collection, complete with James Short's instructions for use:

and looking thro' the small Hole in the End of the Eye-piece, if the Image appear[s] distinct it is well

All these years on, and for many of the telescopes built by Short in the 18th century, the image can still appear well.

Try our free course: telescopes and spectographs





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