Globular clusters resemble stellar jewel boxes featuring roughly spherical assemblies of countless closely-packed stars. This example, NGC 6717, was discovered by William Herschel in 1784 and is located some 20,000 light years from Earth in the constellation Sagittarius. It is one of at least 150 globular clusters orbiting the Milky Way and a spectacular target for the Hubble Space Telescope, which captured this composite image using the Wide Field Camera 3 and the Advanced Camera for Surveys. The brighter stars with criss-cross diffraction spikes, caused by light interacting with the support vanes holding Hubble’s secondary mirror, are much closer to Earth and not part of the cluster.
While NGC 278 may look serene, it is anything but. The galaxy is currently undergoing an immense burst of star formation as revealed in this NASA/ESA Hubble Space Telescope image. However, NGC 278’s star formation is somewhat unusual: why is it only taking place within an inner ring some 6,500 light-years across and not extend to the galaxy’s outer edges?
Despite more than seven weeks having passed since opposition, the Solar System’s largest planet Jupiter is still big and bright in the UK evening sky of May, highest in the south around 10pm BST. Find out about the phenomena of Jupiter and its moons that you can see from the British Isles for the remainder of the month, starting with a transit of Jupiter’s Great Red Spot on 19 May.