As you might know, the sky is due to get a new star any time now, in a few months at most.
What is happening? The recurrent nova T Coronae Borealis, by far the brightest one known, is a star* in the northern constellation Corona Borealis that, once every 80 years or so, increases in brightness from completely invisible by naked eye to among the ~100 brightest in the night sky. This increase is called a nova, from the Latin word for new, as it looks like a new star has appeared.
Where can i see it from? Basically all human inhabited latitudes, all except the far south. In the northern latitudes, however it is visible the entire night, while near and below the equator you will need to 'catch' it at the right time of night, which in August and September is just after sunset.
How will it look? Let's not get your hopes up too high. It will, at the brightest, reach a magnitude around 2 at most, so about as bright as the north star, relatively unremarkable and completely unnoticeable as unique to someone who doesn't know where to look. But still, it's the most visible sudden change to the relatively fixed pattern of the heavens any of us will live to see, so you should still go give it a look.
Where is it? Currently, the constellation is best visible about 1 or 2 hours after sunset. You will need to be relatively far away from light pollution, so at least a couple dozen stars are clearly visible. While learning the constellations, and finding the star by orienting via those is imho half the fun, you could use one of many sky map apps and websites to tell you the star's location. If it didn't happen yet, there should be nothing visible at that location. However, if there is, congrats! You just did an astronomy™ :3
It will appear in the circle next to the star labeled ε
Why is this happening? Most stars spend most of their lives in a stable, hydrogen fusing state. However, when hydrogen in their cores begins to run out, they switch to helium fusion, which makes them swell up to enormous sizes, turn red due to lower surface temperature, and are thus called red giants. After this helium runs out, the star will (in most cases) throw off the inflated outer layers, while its hot, dense core shrinks and keeps on glowing due to how hot it is, while not actually doing any fusion and not producing any new energy. Those are called white dwarfs, and because they don't fuse, aren't technically stars at all, therefore the asterisk in the first sentence of this post. The T-CrBo system is a red giant and white dwarf binary, where the red giant has grown so big, that the parts of it closest to its partner aren't gravitationally bound to it anymore. Therefore, the gas falls and accumulates on the white dwarf's surface (which otherwise has no hydrogen on its own), untill a critical point is reached where the pressure of the gas causes it to all fuse at once, resulting in a huge thermonuclear explosion bright enough to be seen from over 2500 light years. The explosion however, isn't big enough to blow the dwarf apart, and it starts accumulating new matter from its partner right away. Because of this, it with re-explodes every 8 decades, and it is due to go any day now.
