Mrs Pam Arnold-Palmer, a direct descendent of Nevil Maskelyne (1732-1811), recently donated to the Museum a fascinating collection associated with the fifth Astronomer Royal, who worked at the Royal Observatory, Greenwich from 1765 until his death in 1811. The objects range from letters to medals, notebooks to clothing, chronometers to sketches. Maskelyne is principally known for creating the first Nautical Almanac, published in 1766, which provided the tables seamen needed to enable them to find longitude from sextant measurements of the Sun, Moon and stars. The medals show how widely his work was appreciated as they include examples from Russia, France and USA, as well as the Copley gold medal of the Royal Society of London. Maskelyne’s international links are also highlighted by his correspondence with astronomers in other parts of Europe.
The letters, notebooks and accounts contain much interesting material about Maskelyne’s role in preparing the scientific work of several voyages of exploration. They reveal the equipment he recommended and some of his efforts to secure the services of suitable astronomers to carry out observations. These documents are a fascinating combination of the official and the personal, throwing light on his life at Greenwich and his recipes for various medicinal remedies, as well as his work as Astronomer Royal. The clothing includes dresses belonging to his wife, Sophia, and only daughter, Margaret, as well as a padded silk observing suit sent from India by his brother-in-law, Robert Clive. The personal nature of much of this material helps to provide a more rounded picture of Maskelyne than emerges from the official records of the Observatory, or from more recent accounts of the story of finding a method of measuring longitude at sea.
‘Portrait of Nevil Maskelyne by John Russell RA, made when Maskelyne was in his forties’ (ZBA4305)
The Perseids, one of the best-known and most spectacular annual meteor showers, peaks this year between 12-13 August.
The best times to view from the UK will be in the early morning hours of Thursday 12th and Friday 13 August, between about midnight and dawn. Weather permitting, viewing conditions should be ideal this year with the recent new Moon (10 August). At the maximum there could be over 80 meteors per hour.
The Perseids is a bright meteor shower associated with comet
Swift-Tuttle. As the Earth’s orbit passes through
that of the comet, tiny dust particles in the comet’s wake are swept up
by the Earth, entering the atmosphere at speeds of over 215,000 km/h and burning up. This produces the effect that we see as ‘shooting stars’ – meteors.
Perseid
meteors can be seen during late July and early August, falling off rapidly after a peak
around 12 August. It’s thought that the shower as a whole may be about 160,000 years old but the majority of what we can see is 5000 years old.
The ‘radiant’ of the shower (the point from which meteors appear to emanate) is the constellation Perseus, hence the name. The meteors can appear in any part of the sky, but the best place to look is usually about 1-2 handspans from the radiant, quite high in the northeastern sky.
In
clear weather, you should be able to spot a meteor every few minutes or
so. Most appear as flashes of light lasting less than a second, but
some may be more dramatic and leave more persistent trails. NB your eyes will take about 20 minutes to adapt to the dark. You’ll need to scan the sky for the
random flashes so it’s best not to use a telescope.
You can share your observations online via the Twitter Meteorwatch project – see http://meteorwatch.org/ for details.
Meteor showers are never completely predictable, and last year there was a second peak nearly a day after the main one.
More information about this meteor shower can be found in the Royal Observatory’s Perseids fact file.