GCSE Astronomy Controlled Assessment:
B4 – Constellation Photography
For my coursework I have chosen to attempt photography of three different constellations in the night sky. I will go out on three separate dates to take photos then select the best photographs to use for the analysis. I will then aim to identify colours and magnitudes of my photographed stars using comparisons with reference stars for which I have collected known magnitudes from official sources. Explanation of used Astronomical terms
Constellation – A group of stars seen from Earth as forming some sort of recognisable pattern in the sky. These are usually given names due to their resemblance to mythological creatures. Asterism – a prominent pattern of stars in the sky; usually part of a bigger constellation. Reference star – a star with a known magnitude used to compare against others to determine estimates for apparent magnitudes. Star chart – a chart used to show the position of stars in the sky when viewed from a particular point on Earth at a particular time. Magnitude – the brightness of a star. For each whole number above 0, the brightness of the star decreases by x2.5. Meaning the magnitude rating would be 1=2.5, 2=6.25, 3=16 etc. Colour – the surface colour of a star which depends on its temperature and chemical composition. Red stars being the coolest and white being the hottest. Sky glow - the illumination of the sky caused by lighting in urban areas, usually from floodlights, streetlamps etc. Circumpolar – where a star or constellation is situated around or inhabiting one of the earth's poles. Therefor it can be seen all year round due to its position such as Polaris, the North/Polar star. Bayer – a Greek letter of the alphabet assigned to stars in a constellation to rank them in order of apparent magnitude. Longitude – The angle between the Prime meridian (Greenwich), the centre of the Earth and your position. Measure in degrees East and West. Latitude – The angle between the equator, the centre of the Earth and your position. Latitude is measured in degrees north and south of the equator. Variable star – When the apparent magnitude of an observed star fluctuates due to the eclipsing caused by another star in which it is locked in orbit with. It can also be caused intrinsically through the shrinking and swelling of the star itself. Background information on the constellations
A Greek polymath, Ptolemy, was the first to publish an official list of 48 constellations which dates back to the 2nd century. This list has since been extended to 88 by the Astronomical union in 1922. Ptolemy, however, was not the first to document the night sky; ancient civilisations such as the Babylonians and Chinese have been found to have had their own system of documenting the sky dating back thousands of years. In 1603, Johann Bayer (A German astronomer), introduced a system of ranking stars on their apparent magnitude. He assigned each star in a constellation a Greek letter, with Alpha being the brightest and next brightest star being Beta, etc. Many people think of stars in a constellation as being close to each other in actual physical existence. This, in most cases, isn’t the case; stars in constellations only appear to be next to each other because of the angle we view them from when looking at them from Earth. Stars usually are millions of miles away from each other in reality. Planning
I plan to take photographs of 3 constellations from house garden which is located in Carlton, Nottingham (Suburbs). This is admittedly not the optimum observation location due to slight sky glow caused by street lamps and lights from neighbouring houses. It is; however, better than being close to the inner-city which would undoubtedly prove to have a significantly larger amount of light pollution. An ideal location would be somewhere further away from the city centre, preferably in the countryside where there would be close to no sky glow...
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