The skies above us are changing constantly as the Earth beneath our feet makes its way around the Sun, and the planets and stars above us make their own journeys. It means that many objects are out of our view for much of the time – but when they are visible, it is amazing how much you can see. As Ashley Chrimes from Warwick’s Department of Physics explains, it is even possible to snap a good photo of the Moon.
You may know how to spot a shooting star or recognise Orion’s Belt, but because the Earth rotates around the sun and the other planets do the same, we can’t see everything all of the time. So what can you see in April and May this year in the UK and where in the sky are they? Here’s a list of targets - the next time you have a clear night, have a go at seeing as many as you can.
These can all be seen with just your eyes, even from a light polluted area. Binoculars or a telescope will allow you to see fainter objects, and in more detail. To help you find planets, stars and other astronomical objects, you can install some planetarium software such as Stellarium (free to download, and available here). Remember: when looking at a star chart in the dark, try using a red light (or put red paper over a torch) or use ‘night mode’ on Stellarium.
If you need to work out the direction you’re facing, you can find advice in the article on Constellations.
Venus: the second planet from the Sun will be visible in the evening sky throughout April and May, appearing as the bright star in the west after sunset. If you have a small telescope, or can hold a pair of binoculars very still, you might be able to see that Venus has phases like the Moon – for example, sometimes you’ll see a crescent Venus.
The Moon: our nearest neighbour in space. The dark patches are called seas or maria. These aren’t actually seas, but areas of dark coloured rock that used to be lava lakes several billion years ago. If you use binoculars or a telescope when the Moon isn’t full, the craters and mountains cast shadows near the line between night and day, making them really stand out. The picture to the right was taken with a phone camera, looking through a small telescope eyepiece – you could also try with binoculars, or even just the camera zoom. Use night mode on your camera if you have it, it will take a longer exposure to collect more light.
Red Giants: even with just your eyes, you can see that stars have different colours. Some look redder, others are yellow-ish or white. Low in the west after sunset, you might just be able to see a bright, reddish star to the left of Venus, in the top left of the constellation of Orion. This is Betelgeuse, a red giant. It’s nearly 1000 times bigger than the Sun, 100,000 times brighter, and will explode as a supernova sometime in the next few million years. When it does, it will appear as bright as the Moon. Another red giant you can see is Arcturus - this is the brightest star in the southeast, around half of the way up from the horizon after sunset.
The International Space Station (ISS): this can appear as a bright, steadily moving light as it moves across the sky. It’s about the size of a football pitch, and there are six astronauts on board at any time. We can see it because it reflects the Sun's light – it fades away when it moves into the Earth’s shadow. There’s a neat website which allows you to work out when you can next see the ISS from your home: https://spotthestation.nasa.gov/. To have a good chance, you’ll want the ‘elevation’ to be more than about 30 degrees (more than about a third of the way from the horizon to straight up). That way buildings, trees and other obstacles are less likely to get in the way of your view. You might see other artificial satellites too.
Mars, Jupiter and Saturn: If you get up really early, you can see Jupiter, Saturn and Mars, which appear as the three bright stars low in the southeast about an hour before dawn. With binoculars or a telescope, see if you can spot Jupiter’s bands, or it’s four large moons (Ganymede, Europa, Callisto and Io) – they will appear as fainter points of light all lined up either side of the planet (see the top picture). Can you see Saturn’s rings? And Mars will have a distinct red colour. Make sure you stop observing at sunrise though.
28 April 2020
The Astronomy and Astrophysics group at Warwick is interested in a huge range of scales across the Universe: planetary systems, how they form, live and die; stars, stellar binaries and and the exotic physical processes that they allow us to explore; as well as the transient events which mark the end of stellar lifetimes and the galaxies stars inhabit across the Universe. The group started in September 2003 and is both an observational and theoretical group. The group makes use of a wide range of ground-based telescopes, such as ESO's Very Large Telescope (VLT) in Chile and the Isaac Newton Group of telescopes (ING) in the Canary Islands, or the Atacama Large Millimetre Array (ALMA), as well as space telescopes such as NASA's Chandra and ESA's XMM-Newton X-ray observatories and the Hubble Space Telescope. The Warwick astro group partners in the four large spectroscopic surveys (DESI, SDSS-V, WEAVE, and 4MOST) that will start operations throughout 2020-2021.
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