Andromeda, The Galaxy That Will Collide With The Milky Way, Is Already Visible To The Naked Eye In The Sky


This is what Andromeda galaxy will look like in the night sky if it were brighter.

Andromeda is on a striking course with our galaxy. Now begins the perfect time of year to capture it with the naked eye. 

Our galaxy, the Milky Way, and its neighbor are twice its size, Andromeda, are on a striking course. Both are approaching each other at a speed of 113 kilometers per second due to gravitational pull, and although they are predicted to collide in 4.5 billion years, their outer layers have already begun to merge. 


Meanwhile, people on Earth have best opportunity to spot Andromeda, also known as Messier 31, with the naked eye.  


From mid-August to November, the spiral galaxy become visible in the night sky of both hemispheres of our planet. Despite being located 2.5 million light-years away, Andromeda take over a quarter of a degree in the sky. This is equivalent to half the width of a full moon, according to NASA. 

Andromeda Galaxy in a clear sky with no light pollution. Photo: Earth Sky

When will the Andromeda galaxy be visible? 


Due to its remoteness, Andromeda has a disperse glow. Therefore, to spot it with the naked eye, it is not enough to have a clear sky, but also that there is an absence of lunar brightness and small amount of light on the surface. 


For this reason, although the galaxy already become visible in the sky on these dates, it is best to observe it on nights close to the new moon phase. In August, this stage will come in the last week of the month (from August 24 to 31). 

           Location of Andromeda in the Peruvian sky at 3 am on August 24. Image: Stellarium / The Republic

How to locate Andromeda in the sky? 

The galaxy appears above the horizon, heading towards northeast, around midnight in Peru and other countries in the southern hemisphere (Argentina, Chile, etc.), and hours earlier in the northern hemisphere (Mexico, Spain, etc.). 


It is discovered next to the Andromeda constellation —hence its name—, just at the height of the character's 'belt'. Meanwhile, the Pegasus constellation, identified by having a quadrilateral formed by its stars, can serve as a guide to locate the galaxy. 

The star Mirach can also help locate the Andromeda galaxy. Image: Stellarium / The Republic

The finest time to see Andromeda is between 2:00 am and 3:00 am, when it is located in the north, at a higher point in the sky. 


To the naked eye it will look like a small cloud with some detail, but if you use binoculars, you can clearly glimpse the majesty of this neighboring galaxy. 

Location of the Andromeda galaxy (no illustration of the constellations). Image: Stellarium / The Republic

Andromeda has an apparent magnitude of 3.5 (the lower the number, the brighter), which makes it clearer than most visible stars (magnitudes 4 to 6), but less conspicuous than naked-eye planets. (Magnitudes from 1 to less than 0). 


For this reason, astronomical observation experts suggest that anyone who decides to venture in search of Andromeda or any other deep space object should first try to adapt their eyes to the darkness of the sky. 

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