Constellation guide to the 88 official constellations which divide up the sky. These constellations are used to help navigate the celestial sphere. The Constellations are patterns in the sky which have been to invented and have deep mythology behind them. Constellations cover massive areas in the sky and as such are very easy to find.
- Tips for Getting Started in Astronomy
- Dark Eye Adaption - How We See In the Dark
- Light Pollution
- Using Star Charts and Measuring Distance
- Constellation Guide
- Binocular Astronomy
- Moon Watching - How to Observe the Moon
- Buying Your First Telescope
- Your First Night With Your First Telescope
- Sky Orientation through a Telescope
- Polar Alignment of an Equatorial Telescope Mount
- Useful Astronomy Filters for Astrophotography
Eridanus is a mythical river associated with Phaëton, and is the sixth largest of the 88 modern constellations. It was also one of Ptolemy's 48 constellations.
At its southern end is the first magnitude star Achernar (α Eri). Achernar is a very peculiar star because it is one of the flattest stars known. Observations indicate that its radius is about 50% larger at the equator than at the poles. Responsible for this is the fact that Achernar is spinning extremely fast. Another well-known star in Eridanus is ε Eridani, which has been popular in science fiction because it is relatively close and relatively sun-like. It is now known to have at least one planet, which is thought to be a gas giant, like Jupiter.
Eridanus is associated with two Greek myths, both likely to be derived from the shape of the constellation that of a very twisty path. Eridanus was sometimes considered to be a river which flowed from the waters of Aquarius. Eridanus was more usually connected to the myth of Phaeton, who took over the reins of Helios' sky chariot, but didn't have the strength to control it, and so veered wildly in different directions. The result was that sometimes the chariot got too close to earth, creating desert and burning people's skin (a myth they considered to explain the skin of the Ethiopians).
Notable Objects in Eridanus
NGC 1535 is a small blue-gray planetary nebula visible in small amateur telescopes.
Photos of Eridanus
I have no photos of Eridanus yet.
Northern Circumpolar Constellations
These constellations can be viewed all year round in the Northern hemisphere as they move in a counterclockwise direction around the north celestial pole without setting or dipping below the horizon.
Northern Spring Constellations
These Northern constellations are best viewed around the spring months. The rest of the year the constellation will not rise during the night.
Northern Autumn Constellations
These Northern constellations are best viewed around the autumn months. The rest of the year the constellation will not rise during the night.
Last updated on: Wednesday 24th January 2018
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