Of the 88 constellations, the largest is Hydra with an area of 1303 square degrees. It covers more than 7 hours of right ascension (105° in the sky). It is more than 19 times as large as the smallest, Crux, which has an area of just 68 square degrees. Equuleus (87th), is not much larger with an area of 72 square degrees. Sagitta is the 86th, area 80 square degrees, and Circinus, 85th, with an area of 93 square degrees. None of these four small constellation includes any objects of particular interest. It is useful to know some of the special terms for various parts of the sky. As seen by an observer, half of the celestial sphere is invisible, below the horizon. The point directly overhead is known as the zenith, and this point is shown on the monthly charts for several different latitudes, where it is an important reference point. The (invisible) point below one’s feet is the nadir. The line running from the north point on the horizon, up through the zenith and then down to the south point is the meridian. This is an important invisible line in the sky, because objects are highest in the sky, and thus easiest to see, when they cross the meridian in the south. Objects are said to transit, when they cross this line in the sky. Of the chondrites, the most important scientifically are the carbonaceous chondrites, like the Winchcombe meteorite. Apart from the chondrules, these may contain organic material (such as amino acids), water and pre-solar grains. These compounds are essential for life, and there is an opinion that life on Earth has arisen because these materials have been delivered by carbonaceous meteorites or carbonaceous minor planets that have impacted on the Earth.

NIGHT SKY ALMANAC 2023: A stargazer’s guide - Goodreads NIGHT SKY ALMANAC 2023: A stargazer’s guide - Goodreads

The most famous carbonaceous chondrite meteorite is probably the Murchison meteorite, observed to fall near Murchison, Victoria, Australia on 28 September 1969. Both Murchison and the recent Winchcombe meteorite belong to the group known as the CM meteorites. Their material appears to resemble that collected by the Hayabusa 2 spaceprobe from the minor planet (162173) Ryugu, and returned to Earth in December 2020. The Murchison meteorite has been particularly important and the subject of numerous, significant studies. It has been found to contain a phenomenal number of molecular compounds (at least 14,000), including some 70 amino acids. Some estimates put the number of potential compounds in the meteorite at hundreds of thousands, or even as high as one million. In January 2020, an international team of cosmochemists announced that some silicon carbide (SiC, carborundum) particles from the Murchison meteorite were the very oldest particles ever detected. They had anomalous isotopic ratios of silicon and carbon, implying that they were formed outside the Solar System. These grains have a suggested age of 7000 million years, some 2500 million years older than the Solar System itself.The position of the Big Dipper (the Plough), throughout the year, in relation to the northern horizon and Polaris, the Pole Star.

Night Sky Almanac 2023 | Storm Dunlop | download on Z-Library Night Sky Almanac 2023 | Storm Dunlop | download on Z-Library

January 31 • Mars is occulted by the Moon. Times of disappearance and reappearance are given for Houston and Mexico City (as seen from central USA). This ebook contains the following accessibility features which, if supported by your device, can be accessed via your ereader/accessibility settings: Follow the progress of constellations throughout the seasons with this beautiful companion to the night sky from Astronomy experts Collins.February 28 • In the north, the Moon is lining up with Elnath (β Tau), Mars, and Aldebaran. (as seen from Sydney). Horizon window, from the northern horizon (solid line at the bottom) to the zenith (the dotted line) for the latitude of 50°N. Running south from Orion is the long constellation of Eridanus (the River), which begins near Rigel in Orion and runs far south to end at Achernar (α Eridani). To the south of Orion is the constellation of Canis Major and several other constellations, including the oddly shaped Carina. The line of Orion’s Belt also points southeast in the general direction of Sirius (α Canis Majoris), the brightest star. Almost due south of Sirius lies Canopus (α Carinae), the second brightest star in the sky. Observers at 50°N may occasionally be able to detect bright Deneb (α Cygni) and Vega (α Lyrae) skimming the horizon, together with portions of those particular constellations, although most of the time they will be lost in the extinction that occurs at such low altitudes. Below Cancer is the very distinctive asterism of the ‘Head of Hydra’, consisting of five (or six) stars, that is the western end of the long constellation of Hydra, the largest constellation in the sky, that runs far towards the east, roughly parallel to the ecliptic. Alphard (α Hydrae) is south, and slightly to the west of Regulus in Leo and is relatively easy to recognize as it is the only fairly bright star in that region of the sky. North of Hydra and between it and the ecliptic and the constellation of Virgo are the two constellations of Crater and Corvus. Farther west, the small constellation of Sextans lies between Hydra and Leo.

Night Sky Almanac 2023 By Storm Dunlop, Wil Tirion, Royal

Cygnus lies along the line of the Milky Way, the disk of our own Galaxy, and provides a wealth of stars and clusters to observe. Just to the left of the line joining Deneb and Sadr, the star at the centre of the outstretched wings, you may, under very clear dark skys, see a region which is darker than the surroundings. This is called the Cygnus Rift and is caused by the obscuration of light from distant stars by a lane of dust in our local spiral arm. the dust comes from elements such as carbon which have been built up in stars and ejected into space in explosions that give rise to objects such as the planetary nebula M57 described above. All this complexity became redundant, of course, as soon as the view of Copernicus prevailed in which the Earth itself orbited the Sun. It became apparent that the planets displayed retrograde motion when the Earth ‘caught up’ and ‘passed’ the planets in their orbits. Many different cultures had specific names for the Full Moon, depending on the time of year. Even in a single culture, the actual names often varied between different tribes, so there may be more than one name used for a particular Full Moon. The interval between successive Full Moons (or between any other specific phases of the Moon) is known as the synodic month, and is, on average, 29.53 days, so the names have come to be associated with modern calendar months. One of the most commonly known sets of names is that used by the various tribes in North America. These are: For observers in the far north, most of Cygnus, with its brightest star, Deneb (α Cygni), is visible in the north, and even Lyra, with Vega (α Lyrae) may be seen at times. Most of the constellation of Hercules is visible, together with the distinctive circlet of Corona Borealis to its east. Observers farther south may see Deneb and even Vega peeping over the northern horizon at times during the night, although they will often be lost (like all the fainter stars) in the inevitable extinction along the horizon. Eventually, Julius Caesar instigated the Julian calendar reform. Months alternated between 30 and 31 days. This was slightly too long, giving 366 days, so one day was removed from the last month of the year: February, to give it 29 days. An additional day was returned to February every four years, to keep things in step with the Sun. One month, Quintilis, was named Julius (the month of Caesar’s birth).April from Aprilis (the reason for this one is uncertain, and possibly related to the raising of hogs)