Learn to orientate on the night sky
Posted by Mike Lewis on April 17th, 2019
[Guest post] Initially published on Astro Apprentice
You enjoy a nice and sunny day with 100% chances of clear skies for tonight. You can’t wait to get out after the sunset, find a place with a good horizon, away from city lights and explore the night sky. But what should you start with, how to prepare yourself? A sky map for your geographical location (you can find on Heaven’s Above such charts) or an app on your phone with the same functionality in mind is enough (Sky Map from Google is available on multiple platforms).
With the Sun up or just set you know that West is where it set (it will rise in the morning at East). But with just the stars on the sky the best way to orientate yourself is to find the North star. Maybe you already know 2 constellations that allow us to identify it (in the Northern Hemisphere) – Big Dipper(Ursa Major) and Little Dipper (Ursa Minor). Multiplying with 5 the distance between the last 2 stars of the big dipper will get us to Polaris (the North star). We then draw an imaginary line from it to the horizon – and that’s how you found the North point. In the back you’ll have South, on the right West and East on your left.
Humans have drawn imaginary lines connecting various stars since immemorial times. These represented different animals, beliefs or patterns. Different civilisations imagined a variety of constellations. We now have agreed on 88 modern constellations split in 2 hemispheres (northern and southern) – they were agreed by the International Astronomical Union in 1922. The full list can be found here
Starting from the Sun we have 4 telluric planets: Mercury, Venus, Earth and Mars – and another 4 gas giant planets: Jupiter, Saturn, Uranus, Neptune. All of these are observable by amateur astronomers with binoculars and preferably telescopes. Just to avoid confusion – all of them can’t be usually observed in the same night – you should check a sky map / app with the updated planets positions for your local time and specific latitude and longitude.
At some time in the night you may be noticing is that the sky at a whole is moving quite fast from East to West. That’s called an apparent motion – we (the planet Earth) are moving actually. As everything will set to West we will start recognising constellations and find objects from the West. This activity will greatly enhance your pattern and shape matching abilities. Using maps and identifying constellations based on it will help you a lot.
Meteors, Comets, Satellites, other objects
While spending more time under a clear sky you may notice other objects as well. Commonly known as “Falling stars”, meteors are really pieces of rocks that burn in the Earth’s atmosphere. We have periodic meteoric currents (debris left by comets) and sporadic meteors (that don’t belong to any current). Comets are rocky / icy small Solar System bodies that, when passing close to the Sun, warm up and begin to release gases. This produces a visible atmosphere (coma), and sometimes also a tail. Depending on your location you may notice a bunch of satellites and plains getting a bit brighter for a moment and then losing their brightness gradually.
Wrap it up
Actually learning the night sky as a whole, with constellations, star names, recognizing planets and other objects positions (like deep sky objects) requires time and practice. I don’t like to call it “stargazing” but you may perceive it this way. It’s a fun and relaxing hobby (becoming an amateur astronomer). Processing that much information and getting used to the idea that the universe is a lot bigger than you expected can be hard to grasp. But it’s also beautiful at the same time.
Like it? Share it!
About the AuthorMike Lewis
Joined: April 17th, 2019
Articles Posted: 1