What is the Little Dipper?
The little dipper is an asterism, better known as a popularly know pattern of stars, which are a part of the larger constellation named ‘Ursa Minor’ or ‘The Little Bear’.
Ursa Minor is majorly made up by the Little Dipper, as the handle is seen as the bear’s tail and the dipper cup makes up its flank.
The most famous star known in this constellation is named ‘Polaris’, more commonly known as the North Star/ North Pole. This is because it is perceived to be in alignment with the axis of the Earth.
When looking up into the sky it looks like all of the stars in the Northern Hemisphere rotate around Polaris as the Earth spins, but Polaris seems to stay completely stationary. In the days before GPS, it is believed that travelers would use Polaris as a guide and reference point to their location.
Making up the little dipper is Polaris or Alpha Ursae Minoris at the end of the handle. Making up the rest of the handle is Yildun and Epsilon Ursae Minoris and making up the cup is Alifa al Farkadain, Kochab, Pherkad, and Anwar al Farkdain.
To easily find the little dipper in the sky, you can use Polaris as a reference point, or even easier, you can use the bigger dipper as a more easily visible point of reference.
Why is it only visible in the northern hemisphere?
The little dippers’ relevance to the Northern Hemisphere is simply due to its positioning, noted by Polaris/ The North Star, which reveals the location of the Northern Celestial Pole.
Due to this angle in the sky, it can be used to figure out your latitude on the globe, hence why it used to be a significant source of location and geographic reference for sailors, some still use it as a reference point to this day.
For those of whom live on the equator, Polaris and the Little Dipper will be visible on the horizon. However, it is not visible at all in the southern hemisphere, due to its Northern Axis location.
If you were to sail from Antarctica to the Arctic you would see Polaris and the Little Dipper halfway through your journey as you crossed the equator. As it appeared higher and higher in the sky, it would signify how far North you are.
The relevance of constellations.
The northern hemisphere and the southern hemisphere both have different views of the night sky, as they look at different parts of space.
So, both hemispheres have different constellations that they see and different constellations will be seen depending on each season.
- Winter: Orion, Gemini, Taurus, Ursa Minor.
- Spring: Leo, Virgo, Ursa Minor.
- Summer: Scorpius, Sagittarius, Cygnus, Ursa Minor.
- Autumn: Pegasus, Pisces, Ursa Minor.
- Winter: Lyra, Scorpius, Cygnus, Crux.
- Spring: Andromeda, Pegasus, Crux.
- Summer: Dorado, Orion, Taurus, Crux.
- Autumn: Hydra, Leo, Crux.
As you can see, both hemispheres have one constellation they will see year-round, in the north, this is Ursa Minor, or otherwise known as the ‘Little Dipper’, in the south this is the Crux, also known as the ‘Southern Cross’.
This is due to these constellations being the signifiers of the North and South poles.
How to use the Big Dipper to find the Little Dipper
To find the little dipper, use the big dipper if you are unsure of where it is, although Polaris usually gives it away, due to it being the brightest star in the northernmost part of the sky.
The best time to find it is in June, as the big dipper will be high in the North. Much like the little dipper, it has a bowl and a handle, just larger. Look at the big dipper and find the two stars that make up the bowl furthest away from the handle.
These stars are often referred to as ‘The Pointers’ as they point directly towards Polaris/ The North Star. Now draw a line from the pointers, directly north. Doing this will point you exactly to where Polaris is and henceforth, the little dipper too.
These pointers are named Dubhe and Merak, draw the line from Dubhe to Merak and then onwards to Polaris.
These two pointers are very bright, so will be easy to spot when you are looking for them to point you to the little dipper. It is also convenient that when looking up into the night sky, you will notice that the big dipper and little dippers often are opposite to each other.
When one is pointing upright the other is pointing downwards.
However, the big dipper is a good reference point, as it is the much brighter of the two constellations, and is much larger in size. It resembles a long handled pan, while the little dipper looks much more like a soup ladle or small milk pan.
Should you need more reference, look for an orange-hued star glowing around where the bowl of the little dipper is, this star is Kochab and is the brightest star in the bowl formation of this constellation. Following it is Pherkad, which is much dimmer but makes up a remaining part of the bowl.
While Polaris is a great pointer as to where the little dipper is in the sky, due to its status as the North Star, it has not always been this way, as the Earth wobbles slightly on its axis, the celestial pole, therefore, shifts over many centuries meaning there are different stars that have taken the role of the North pole over time.
It is believed that by the year 2100, Polaris will be even closer to the exact point of the earth’s northern pole. While in around the time of 400BC, Kochab was the North Star.
So, while Polaris is currently a great pinpoint for the north and finding the little dipper, in centuries to come this may not still be the case. Perhaps another star in the little dipper will eventually take its place.
There may even be a chance in a few hundred centuries that the big dipper may be the north most constellation!