Para observar o céu na Cova da Zorra, instale-se confortávelmente lá fora, virado para norte, de costas para a entrada da casa, comece por ir buscar uma cadeira ou espreguiçadeira da piscina, não se esqueça de um agasalho, mesmo no verão há noite frias, por fim agarre uma lanterna com luz fraca para ler mapas (existe um livro em casa), desligue as luzes do exterior da casa e espere um pouco para se habituar à escuridão.
1.Olhando para Norte procure o seu foco, pode ser a estrela mais forte da Ursa Maior (um dos ceus Guardas).
2. Siga em linha recta desde os Guardas da Ursa maior e procure a à Estrela Polar (4 vezes mais que a distância entre os Guardas).
3. Encontrou a Ursa Menor verifique a sua forma.
4. Continue na mesma direcção e encontrará a Cassiopeia (Um M na vertical).
To look the sky at Cova da Zorra, firstly, let’s deal with the comfort aspect. Even in the summer, it will probably get chilly so wrap up warm. Then, to get as comfortable as possible, set up a deck chair or sun-lounger – or a "star-lounger" in this case.
Just before you pop outside to try some real star-hopping, there are a couple of final useful things to have with you: a star chart or atlas, plus a red torch to see the charts, and also where you’re going, without ruining your night vision. And don’t forget a flask of tea and a few biscuits for when you fancy a break.
If you’re new to star-hopping, position your star-lounger north-south and sit with your feet pointing north. This will put you in an ideal position to see several key star-hopping points: the Plough, the North Star and the constellation of Cassiopeia as they’re all around the north part of the sky.
Start using this example. Remember, take it easy, and you’ll be finding your way around the sky in no time.
Star-hop from the Plough to Cassiopeia
1. Find the Plough - The Plough is a shape or ‘asterism’ found in the constellation of Ursa Major, the Great Bear. It’s a good place to start because it’s a recognisable shape. It’s also close to the north pole of the sky, meaning it’s always visible in the night sky.
2. Move from the Plough to the Pole Star
The two right-hand stars of the Plough are known as the Pointers. Extend an imaginary line between them and out of the Plough and they’ll point to the Pole Star, which is also called Polaris.
3. Trace the shape of Ursa Minor
The Pole Star is the main star of the constellation Ursa Minor, the Little Bear. This is shaped like a smaller, fainter version of the Plough and you can trace its form arching off from Polaris. Well done, you’ve found a new constellation.
4. Move on to Cassiopeia
Continue on in the same direction you took from the Plough to Polaris, for around the same distance again. You’ll find the distinctive ‘W’ of stars that make up the constellation of Cassiopeia. That’s it, a successful star-hopping session.
Como medir as distancias em graus, entre estrelas, apenas olhando para o céu?
Um punho fechado, à distancia de um braço esticado, equivale a 10º, por isso este pode ser usado para fazer estimativas das distancias entre as estrelas
How can You measure distance by degrees just by looking at the Sky?
Without looking at star maps as a reference, you can estimate degrees of distance in the celestial sphere by using a couple of tricks.
In general, if you hold your hand in a fist vertically at arm’s length, it measures about 10° against the sky.
Looking from Earth, the distance between the two stars that point to the North StarMerak and Dubhe, which form the right side of the Big Dipper’s bowl, is approximately 5°.
Also, remember that your celestial meridian, the imaginary line arcing above your head from your northern celestial horizon to your southern celestial horizon, equals 180°, and that your zenith is at 90° from the horizon.
Stars within a constellation are light-years away from each other. They appear to be visually connected only when viewed from Earth.