She Is A Shining Star

Jupiter and Io, taken by the Cassini spacecraft in 2001

Space Shuttle Discovery STS-133

This is an image of the planet Uranus taken by the spacecraft Voyager 2 in 1986.

Constellations: Chamaeleon

Chamaeleon is a small constellation in the southern sky. It is named after the chameleon, a kind of lizard. It was first defined in the 16th century.

Deep-sky objects

In 1999, a nearby open cluster was discovered centered on the star η Chamaeleontis. The cluster, known as either the Eta Chamaeleontis cluster or Mamajek 1, is 8 million years old, and lies 316 light years from Earth.

The constellation contains a number of molecular clouds (the Chamaeleon dark clouds) that are forming low-mass T Tauri stars. The cloud complex lies some 400 to 600 light years from Earth, and contains tens of thousands of solar masses of gas and dust. The most prominent cluster of T Tauri stars and young B-type stars are in the Chamaeleon I cloud, and are associated with the reflection nebula IC 2631.

Constellations: Cetus

Cetus is a constellation. Its name refers to Cetus, a sea monster in Greek mythology as both Perseus and Heracles needed to slay, sometimes in English called ‘the whale’. Cetus is in the region of the sky that contains other water-related constellations such as Aquarius, Pisces, and Eridanus.

Mira (“the Wonderful”), designated Omicron Ceti, was the first variable star to be discovered and the prototype of its class. Over a period of 332 days, it reaches a maximum apparent magnitude of 3 - visible to the naked eye - and dips to a minimum magnitude of 10, invisible to the unaided eye. Its seeming appearance and disappearance gave it its common name, which means “the amazing one”. Mira pulsates with a minimum size of 400 solar diameters and a maximum size of 500 solar diameters. 420 light-years from Earth, it was discovered by David Fabricius in 1596

Deep-sky objects

Cetus lies far from the galactic plane, so that many distant galaxies are visible, unobscured by dust from the Milky Way.

Of these, the brightest is Messier 77 (NGC 1068), a 9th magnitude spiral galaxy near Delta Ceti.

Recently, the galactic cluster JKCS 041 was confirmed to be the most distant cluster of galaxies yet discovered.

NGC 246 (Caldwell 56), also called the Cetus Ring, is a planetary nebula with a magnitude of 8.0, 1600 light-years from Earth.

Constellations: Cassiopeia

Cassiopeia is a constellation in the northern sky, named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivaled beauty. Cassiopeia was one of the 48 constellations listed by the 2nd-century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today. It is easily recognizable due to its distinctive ‘W’ shape, formed by five bright stars. 

At magnitude 2.2, Alpha Cassiopeiae, or Schedar, is generally the brightest star in Cassiopeia, though it is occasionally outshone by the variable Gamma Cassiopeiae, which has reached magnitude 1.6. The constellation hosts some of the most luminous stars known, including the yellow hypergiants Rho Cassiopeiae and V509 Cassiopeiae and white hypergiant 6 Cassiopeiae.

Deep-sky objects

A rich section of the Milky Way runs through Cassiopeia, stretching from Perseus towards Cygnus, and it contains a number of open clusters, young luminous galactic disc stars, and nebulae.

The Heart Nebula and the Soul Nebula are two neighboring emission nebulae about 7,500 light-years away.

Two Messier objects, M52 (NGC 7654) and M103 (NGC 581), are located in Cassiopeia; both are open clusters.

The other prominent open clusters in Cassiopeia are NGC 457 and NGC 663, both of which have about 80 stars.

There are two supernova remnants in Cassiopeia. The first, designated 3C 10 or just Tycho’s Supernova Remnant, is the aftermath of the supernova called Tycho’s Star. It was observed in 1572 by Tycho Brahe.

Within the 'W’ asterism formed by Cassiopeia’s five major stars lies Cassiopeia A (Cas A). It is the remnant of a supernova that took place approximately 300 years ago (as observed now from Earth; it is 10,000 light-years away), and has the distinction of being the strongest radio source observable outside the Solar System.

The December Phi Cassiopeiids are a recently discovered early December meteor shower that radiates from Cassiopeia.

Neptune ♆

On this day in 1846 was discovered the planet Neptune.

The ice giant Neptune was the first planet located through mathematical predictions rather than through regular observations of the sky. (Galileo had recorded it as a fixed star during observations with his small telescope in 1612 and 1613.) When Uranus didn’t travel exactly as astronomers expected it to, a French mathematician, Urbain Joseph Le Verrier, proposed the position and mass of another as yet unknown planet that could cause the observed changes to Uranus’ orbit. After being ignored by French astronomers, Le Verrier sent his predictions to Johann Gottfried Galle at the Berlin Observatory, who found Neptune on his first night of searching in 1846. Seventeen days later, its largest moon, Triton, was also discovered.

Neptune is invisible to the naked eye because of its extreme distance from Earth. Interestingly, the highly eccentric orbit of the dwarf planet Pluto brings Pluto inside Neptune’s orbit for a 20-year period out of every 248 Earth years. Pluto can never crash into Neptune, though, because for every three laps Neptune takes around the Sun, Pluto makes two. This repeating pattern prevents close approaches of the two bodies.

Nearly 4.5 billion kilometers (2.8 billion miles) from the Sun, Neptune orbits the Sun once every 165 years. 

Uranus’ blue-green color is also the result of atmospheric methane, but Neptune is a more vivid, brighter blue, so there must be an unknown component that causes the more intense color. 

Despite its great distance and low energy input from the Sun, Neptune’s winds can be three times stronger than Jupiter’s and nine times stronger than Earth’s.

Winds on Neptune travel faster than the speed of sound.

In 1989, Voyager 2 tracked a large, oval-shaped, dark storm in Neptune’s southern hemisphere. This “Great Dark Spot” was large enough to contain the entire Earth.

Neptune has five known rings. Voyager 2’s observations confirmed that these unusual rings are not uniform but have four thick regions (clumps of dust) called arcs. The rings are thought to be relatively young and short-lived.

Neptune has 14 known moons, six of which were discovered by Voyager 2.

Triton, Neptune’s largest moon, orbits the planet in the opposite direction compared with the rest of the moons, suggesting that it may have been captured by Neptune in the distant past. 

To know more about the planet Neptune click here and here.

Constellations: Canes Venatici

Canes Venatici is one of the 88 official modern constellations. It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for “hunting dogs”, and the constellation is often depicted in illustrations as representing the dogs of Boötes the Herdsman, a neighboring constellation. Cor Caroli is the constellation’s brightest star, with an apparent magnitude of 2.9. The stars of Canes Venatici are not bright. In classical times, they were listed by Ptolemy as unfigured stars below the constellation Ursa Major in his star catalogue.

Deep-sky objects

Canes Venatici contains five Messier objects, including four galaxies.

One of the more significant galaxies in Canes Venatici is the Whirlpool Galaxy (M51, NGC 5194) and NGC 5195, a small barred spiral galaxy that is seen face on. This was the first galaxy recognised as having a spiral structure, this structure being first observed by Lord Rosse in 1845. It is a face-on spiral galaxy 37 million light-years from Earth.

Other notable spiral galaxies in Canes Venatici are the Sunflower Galaxy (M63, NGC 5055),

M94 (NGC 4736),

and M106 (NGC 4258).

M3 (NGC 5272) is a globular cluster 32,000 light-years from Earth. It is 18’ in diameter, and at magnitude 6.3 is bright enough to be seen with binoculars. It can even be seen with the naked eye under particularly dark skies.

Constellations: Canis Major

Canis Major is a constellation in the southern celestial hemisphere. In the second century, it was included in Ptolemy’s 48 constellations, and is counted among the 88 modern constellations. Its name is Latin for “greater dog” in contrast to Canis Minor, the “lesser dog”; both figures are commonly represented as following the constellation of Orion the hunter through the sky.

Canis Major contains Sirius, the brightest star in the night sky, known as the “dog star”. It is bright because of its proximity to the Solar System. In contrast, the other bright stars of the constellation are stars of great distance and high luminosity. At magnitude 1.5, Epsilon Canis Majoris (Adhara) is the second-brightest star of the constellation and the brightest source of extreme ultraviolet radiation in the night sky.

Hubble Space Telescope image of Sirius A and Sirius B. The white dwarf can be seen to the lower left. The diffraction spikes and concentric rings are instrumental effects.

The red hypergiant VY Canis Majoris is one of the largest stars known, while the neutron star RX J0720.4-3125 has a radius of a mere 5 km.

Deep-sky objects

Canis Major boasts several open clusters. The only Messier object is M41 (NGC 2287), an open cluster with a combined visual magnitude of 4.5, around 2300 light-years from Earth.

NGC 2360, around 15 light-years in diameter, it is located 3700 light-years away from Earth.

NGC 2359 (Thor’s Helmet or the Duck Nebula) is a relatively bright emission nebula in Canis Major, with an approximate magnitude of 10, which is 10,000 light-years from Earth. The nebula is shaped by HD 56925, an unstable Wolf–Rayet star embedded within it.

This photograph of Neptune’s southern hemisphere was taken by the narrow-angle camera on NASA’s Voyager 2 when the spacecraft was 4.2 million km (2.6 million miles) from the planet.

This image of Neptune was taken by Voyager 2’s wide-angle camera when the spacecraft was 590,000 km (370,000 miles) from the planet. 

Constellations: Cancer

Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as one. Its astrological symbol is ♋. Cancer is a medium-size constellation with an area of 506 square degrees and its stars are rather faint, its brightest star Beta Cancri having an apparent magnitude of 3.5.

Artist’s impression of 55 Cancri e near its host star.

It contains two stars with known planets, including 55 Cancri, which has five: one super-earth and four gas giants, one of which is in the habitable zone and as such has expected temperatures similar to Earth.

Deep-sky objects

Cancer is best known among stargazers as the home of Praesepe (Messier 44), an open cluster also called the Beehive Cluster, located right in the centre of the constellation. Located about 590 light-years from Earth, it is one of the nearest open clusters to our Solar System.

M44 contains about 50 stars, the brightest of which are of the sixth magnitude.

The smaller, denser open cluster Messier 67 can also be found in Cancer, 2600 light-years from Earth.