The Sky at Night

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(These are notes for a proposed page on Alusian naked eye astronomy)

Stars

Brightnesses

A star's brilliance is measured by it's magnitude. Each successive magnitude is 2.5 times fainter than the one before it. The average human can see down to magnitude six in a clear and moonless night in the country, away from any other light sources. Magnitude one is defined as being 100 times brighter than magnitude six, and a few stars are brighter than that.

  • Sirius -1 (From Ellenic Seirius - of Seir)
  • Next Five Brightest Stars 0
  • Next Ten Brightest Stars +1

Colour

Most stars appear to be white, but a few bright stars have been observed to have reddish or bluish hues.

Circumpolar

Alusia-circumpolar.jpg

Some stars are circumpolar, i.e. they never rise or set, being always visible in the sky. Instead they seem to scribe a circle around a point in the sky called the North Celestial Pole (or the South Celestial Pole in the Southern Hemisphere). The height of the Pole above the horizon and the number of stars that are circumpolar is defined by the observer's latitude (37 degrees north for Seagate). There is a bright star, Polaris, located near the North Celestial Pole but the South Pole has no such visual aid. Polaris is located at the end of the handle of the Hammer. Lately (Summer 814) there has been talk that the Pole Star should be renamed Engalton.

The pictured constellations are:

  • Bow & Arrow
  • Spider
  • Throne
  • Thor's Hammer (usually referred to as just the Hammer)
  • Infinity (or the Eight)
  • The Wagoner
  • Libram (some cultures call it the Book of Knowledge)

Nomenclature and Co-ordinates

Many of the brighter stars have their own names, most of which are still in common use. There are two, more formal systems of naming, both of which occur within constellations. The first uses the order of brightness using the elven alphabet. The brightest star is assigned the first letter, the second brightest the second letter and so on. Once the elven alphabet runs out, the dwarven one is used. The second method of naming numbers the stars in order of right ascension within the constellation. This method isn't as widely used.

The position of each star is given by the number of degrees eastwards from the vernal equinox (the ascending node), labelled as Right Ascension (abbreviated as RA), and also up or down from the Celestial Equator, labelled as Dec). Stars in the northern celestial hemisphere have positive declinations whereas those in the southern celestial hemisphere have negative declinations.

Constellations

Stars are arranged in groupings called Constellations, and the exact number and groupings depend on which society mapped the heavens.

Zodiacal constellations

Equitorial.PNG

These are the fourteen constellations that the sun, moon, and planets wander through in their path through the sky. In order from the descending node (where the ecliptic crosses the celestial equator going from summer to winter) they are (using the Western Kingdom maps): Maiden, Messenger, Smith, Thief, Lover, Warrior, King, Mother, Magician, Wolf, Void, Reaper, Fool, Farmer.

(to be redrawn later to proper scale and with magnitude and observed colour (if significant))

Maiden.jpg
Messenger.jpg
Smith.JPG
Thief.jpg
Lover.jpg
Warrior.jpg
King.jpg
Mother.jpg
Magician.jpg
Wolf.jpg
Void.JPG
Reaper.jpg
Fool.jpg
Farmer.jpg

Dates that the sun is in each constellation:

  • Maiden - 15 Seedtime, 10 Blossom (ascending node, spring equinox)
  • Messenger - 11 Blossom, 5 Meadow
  • Smith - 6 Meadow, 1 Heat
  • Thief - 2 Heat, 27 Heat (summer solstice)
  • Lover - 28 Heat, 23 Breeze
  • Warrior - 24 Breeze, 18 Fruit
  • King - 19 Fruit, 14 Harvest
  • Mother - 15 Harvest, 10 Vintage (descending node, autumn equinox)
  • Magician - 11 Vintage, 5 Frost
  • Wolf - 6 Frost, 1 Snow
  • Void - 2 Snow, 27 Snow (winter solstice)
  • Reaper - 28 Snow, 23 Ice
  • Fool - 24 Ice, 18 Thaw
  • Farmer - 19 Thaw, 14 Seedtime

(Preliminary notes - to be revised to tie in with Andrew's list of zodiacal stars in Navigation by the Stars)

The Void is significant is that it appears to be a blank piece of sky, although a few keen eyed observers have seen very faint stars in that area. Spyglasses will reveal a few more faint stars and philosophers are still arguing about why this particular area of sky is so devoid of stars compared to the rest of the sky.

The Wolf contains a bright red star, known as the Eye of the Wolf, or Anthor, because of it's similarity to Thunor. When Thunor passes close to Anthor, it looks like the wolf has gained two bright glowing red eyes. Many cultures believe that, at this time, demonic influences are at their greatest. If the full moon is in the Wolf, it is also believed that lycanthropes are at their strongest.

There is a star in the Mother, commonly known as the Awl. This is a holdover from pre-Panjarre maps when the constellation used to be drawn as an old man working on a sheet of leather, rather than an old woman with a spinning wheel. The Awl marked where the tool was held in the hand.

In some cultures, the Warrior has been called 'The Pan' as it can look like a saucepan. The bottom star of the three that depict the Hunter's Sword (or the pan handle), looks fuzzy in spyglasses and has been described as having the colour of pinkish/red. The Warrior also contains 'The Demon Star' as over a period of three months, this star changes noticably in brilliance from magitude 3 down to magitude 5. This star is reddish and there is still some arguments about which fire demon this star is pacted to. Aim appears to be the most popular choice as it has been described as a burning coal that waxes and wanes as it burns.

Other noteworthy constellations

Southern-sky-anaud.gif

In the Southern sky, there is a constellation called Michael's Sword, although many sailors refer to it as the Cross, which can be used to help find the South Celestial Pole. A grouping called the Wains helps find the North Celestial Pole.

Opposite the North Star, from the Wains, is a small constellation known as the Throne. At first glance it looks like a 'W' or an 'M' depending which way it is up.

There is a small grouping of bright stars located just below the constellation of the Dragon. It is not a constellation in itself, being part of Dragon, but it is commonly known as 'Dragon's Gold' or 'Dragon's Treasure'. In Pasifika, it is known as Matariki (Small Eyes) and it's rising, just before the sun after the New Moon, marks the start of the Pasifikan year, and time for planting. On the Alusian Calendar, this occurs on the 7th of Harvest.

Sirius is located in the Horse (usually depicted as Seir's Stallion), so it is sometimes known as the Horse Star. It is the brightest star in the sky. It appears to shine alone but a good spyglass can just make out a faint dot next to it. This star is called 'The Colt'. In places near Arabie, the rising of Sirius in the evening sky, just after sunset, marks the start of the annual river floods. Seir's followers also mark this time in celebration. This usually happens sometime in the month of Thaw.

Wanderers

As well as the fixed stars, there are six other bodies (not counting the Sun and the Moon) that move in the heavens. They all follow a path near the ecliptic (the yearly path that the sun takes through the sky). They are: Ariel, Freya, Thunor, Wotan, Hela, and Merlyn.

Both Ariel and Freya appear either in the eastern sky near morning, or the western sky at evening. Ariel is hard to see as it is always close to the Sun and is usually drowned in the latter's glare. Freya however, is the brightest object in the night sky (excepting the Moon) and is unmistakable. The best time to see them is when they are at greatest elongation from the Sun.

The other four can be at any angle from the Sun and are usually brightest when they are at opposition, i.e. 180 degrees from the Sun. Merlyn is hard to see at the best of times since it is so faint but the others can be picked out easily, Thunor especially since it has a reddish hue.

Occasionally these four can be seen to move backwards in the sky. This is called retrograde motion and several theories have been put forward to explain it. It usually occurs around opposition.

Comets

Guest Stars

Other Phenomena

There is a river of soft light that is inclined roughly 75 degrees to the celestial equator, which is commonly known as the 'Winter River', mainly because it is more prominent in the evening of the winter months. Other cultures have referred to it as the River of Milk or the Milky Way.

Occasionally there are streaks of lights, called meteors, sometimes known as 'falling stars', that appear at random times and places in the sky. However, at certain times of the year, there are showers of them and they appear to radiate from certain points in the sky at different times during the year, but at roughly the same dates each year. Arguments are still raging about why this occurs.

Eclipses