Not visible constellations

Not visible constellations

A constellation is a group of stars of the vault heavenly which enough close relations looked the appearance imagination of a figure onto the sky. A constellation is thus a asterism astronomy, an asterism is a remarkable figure drawn by particularly brilliant stars.  particular. In the sky the stars of a constellation are very remote some of the others but seem grouped together there figures.

Image: by agreement the names of the stars of a constellation are prefixed by a Greek letter followed by the first 3 letters of the constellation, the example: α Ori, β Ori,... (Greek letters: α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ ς σ τ υ φ χ ψ ω).

The Giraffe constellation (Camelopardalis)

When they speak about the constellation of the Giraffe, the astronomers say gladly that it is there where there is nothing, situated between the constellation of the Coachman and the pole star in a rather empty region. In this constellation, two stars only are visible in the bare eye.
It is a question of α Cam, situated in 6939 light years of the Earth and of β cam, a great giant distant from 1100 light years.

The Giraffe is indeed situated in border of the Milky Way, in the northeast of three very rich and easily locatable constellations: Cassiopeia, Cepheus and the Coachman, where we recognize Capella (at the foot of the image). We recognize on the upper of the image Polaris, the pole star, which marks the beginning of the Small She-bear. The Giraffe is centered on the axis Capella-Polaris, in the intersection of this axis and of the continuation of the branch is of Cassiopeia.

This intersection point is situated in the center of a big semicircle which passes by Polaris, Ruchbah (δ Cas), Mirphak (α Per) and Capella. This desert circle contains only weak stars, the most brilliant of which are lower than magnitude 4, and ask for good conditions of visibility to be discernible.

The Lynx constellation (Lyncis)

The Lynx is the another constellation constituted by stars of very weak brilliancy and we can find them only when the conditions of observation are particularly favorable. The Lynx is situated between the Gemini and the Great Bear. We find there among others, a red huge star, α Lyncis, the most brilliant star of the constellation (magnitude is similar 3,14).

Situated in 222 light years, this red giant is 210 times as brilliant as our Sun and 40 times as big. The constellation of the Lynx possesses only one star possessing a proper name and it is not listed in the designation of Bayer: Alsciaukat (31 Lyncis), of Arabic origin meaning thorn, magnitude 4,25.

It is nevertheless only about the most brilliant fifth star of the constellation. It is almost identical in α Lyncis.

Berenice's hair constellation

Coma Berenice, Berenice's hair is little visible east of the Lion and in the North of the Virgo. Berenice's Hair is between Retrievers and Virgo. The astronomer Thycho Brahé did not suspect that following the discovery of this constellation, he had bounded the place of a real nest of distant galaxies. Three main stars, α (46,72 AL), β (29,86 AL), γ (170 AL), constellation are weak (magnitude 4,5) and the hair is visible in the form of a dust of stars only in very good conditions of luminosity.

The constellation is situated in the South of the Great Bear. Leaving of "sleeve" we find in 15° in the South both brilliant stars which form Retrievers, and still in ≈15° in the same direction the stellar heap. When we have already tracked down in this zone the shape of the Great Bear and Arcturus du Bouvier, the location of the zone is rather easy: The main part of the stellar heap is halfway between Arcturus and both stars which mark the before leg of the Great Bear.

The Lizard constellation (Lacertae)

Between the constellations of the Swan and Andromeda is the Lizard.
This constellation was really concerned the heavenly maps to fill a zone devoid of brilliant stars. The Lizard contains few stars and it has a shape of badly defined broken line, its name comes from the shape zigzag described by its most brilliant stars. Furthermore, it is rather difficult to track down. The Lizard does not contain visible heavenly objects in the bare eye.

However, during this century, several novae were observed and there particularly in the 1910s and 1950. The stars which constitute it are weak (magnitude 4). Rather good conditions of visibility are thus needed to guess it.
The constellation is situated in the South of the axis Cassiopeia - Deneb of the Swan, in the continuation of the chain of Andromeda, and the limit between these two groups is not very easy to discover.

α Lacertae, is the most brilliant star of the constellation, which achieves that the magnitude is similar 3,76.
It is a white star twice as big as the Sun, but 25 times as brilliant. It turns on itself there only 17 hours. Other stars of the constellation are all little brilliant.
β Lacertae is only of magnitude 4,42. We find also two heap opened there, NGC 7243 and NGC 7209, as well as the galaxy activates BL Lacertae.