Update README.md

Author: rpn1966

README.md

@@ -10,7 +10,7 @@ The first extrasolar planet discovered orbiting a Sun-like star was 51 Pegasi b
 ![Alt](./ReadmeFigures/f1.png)
 
 The launch of the Kepler spacecraft in March 2009 heralded a dramatic improvement in our knowledge about exoplanets (Borucki et al 2010). Kepler was launched into an Earth-trailing heliocentric orbit, which allowed it to stare
-continuously at one region of the sky for a period of approximately 4 years. The mission used the transit detection technique to find planets. This method looks for the periodic dimming of the light from a star as seen by an observer when a planet passes in front of the star during its orbit (see the figure above). For geometrical reasons, most planetary orbits around distant stars do not cause the planet to pass in front of the star when observed by the Kepler spacecraft. For a randomly orientated orbit the probability of observing a transit is typically about 1%, so for this reason the Kepler spacecraft monitored the brightness of approximately 150,000 stars for the duration of the mission, resulting in the discovery of 4717 planet candidates, of which 2303 have been confirmed to be genuine exoplanets. Note that there are numerous ways in which different astrophysical phenomena can mimic a transiting planet, hence the need for additional observations that are able to confirm the planetary nature of the Kepler planet candidate systems.
+continuously at one region of the sky for a period of approximately 4 years. The mission used the transit detection technique to find planets. This method looks for the periodic dimming of the light from a star as seen by an observer when a planet passes in front of the star during its orbit (see the figure above). For geometrical reasons, most planetary orbits around distant stars do not cause the planet to pass in front of the star when observed by the Kepler spacecraft. For a randomly orientated orbit the probability of observing a transit is typically about 1%, so for this reason the Kepler spacecraft monitored the brightness of approximately 150,000 stars for the duration of the mission, resulting in the discovery of approximately 4800 planet candidates, of which about 2500 have been confirmed to be genuine exoplanets. Note that there are numerous ways in which different astrophysical phenomena can mimic a transiting planet, hence the need for additional observations that are able to confirm the planetary nature of the Kepler planet candidate systems.
 
 The Kepler spacecraft produced data in the form of light curves for each of the observed stars – data files that list the time of observation and the brightness of the star over an extended period of time. These light curves were then processed to remove artefacts and other unwanted features from the data (a process known as detrending) prior to the data being made available for scientists to analyse. See the figure below for an example of a detrended light curve. You will use these detrended light curves in your analysis, and one of the things that you will learn is how to download the data files for individual systems from the Kepler data archive so that you can choose which systems to analyse.
 ![Alt](./ReadmeFigures/f2.png)