Night Sky Almanac 2023: A stargazer’s guide

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The planet (P) orbited on a small circle, carried round a larger circle, centred at the deferent (D), offset from the Earth (E). Because of the notion that movements in the planetary realm could only occur in ‘perfect’ circles, the idea was introduced that the planets moved on small circles (epicycles) that were themselves carried round the Earth on circular orbits. This concept was first introduced by Apollonius of Perga, whose dates are unknown, but who lived around 240 to 190 BCE. He studied geometry and astronomy, but most of his writings are lost. The crater Apollonius on the Moon carries his name. The various concepts were developed by the Greek astronomer Hipparchus (about 190 to 120 BCE), who also has a lunar crater named after him.

Night Sky Almanac 2023: A stargazer’s guide – HarperCollins Night Sky Almanac 2023: A stargazer’s guide – HarperCollins

The initial object (a small asteroid) was estimated to have a diameter of about 20 metres and approached from the direction of the Sun, which is why it was not detected before arrival. Following the airburst, some fragments survived to reach the ground, west of Chelyabinsk. The snow-covered ground made the recovery of these relatively easy. Most, however, found their way into private hands. The largest known fragment was eventually recovered from the frozen Lake Cherbakul after a long recovery process. This proved to have an initial mass of 654 kg. All the recovered meteorites were found to be ordinary stony chondrites (see here). Learn more about the full Moons of August, how they got their name, and best days by the Moon in our August Moon Guide. August 11/12/13: The great Perseid Meteor Shower will have excellent dark sky viewing conditions, since the peak is close to the new Moon (i.e., no moonlight to interfere!). The Perseids deliver a meteor a minute in dark cloudless skies. These shooting stars are best seen after midnight. Learn all about the Perseids. SummerStargazing August’s full Sturgeon Moon reaches its peak on Tuesday, August 1, 2023. This is the first of two Full Moons for August. It can be referred to as a ‘super Moon’ because the moment of Full Moon occurs with two days of perigee (when the Moon is the closest to the Earth in its orbit. Learn more about supermoons. August 28: Venus, having just moved from an evening to a morning star at mid-month, has now brightened to a dazzling magnitude -4.5 and is an eye-catching spectacle at 5:30 AM. (Remember, the lower the magnitude, the brighter thestar.)On very rare occasions, under very dark skies, it is just possible to make out the dwarf planet with the naked eye, when it reaches magnitude 6.7. Generally, however, it requires telescopic or binocular aid to become visible. At opposition in 2023 it will reach magnitude 7.4. It did not come to opposition in 2022. If, using something like 8 by 40 binoculars, you have seen M31 as described above, it might well be worth searching for M33 in Triangulum. Triangulum is In this book, reference is sometimes made in the text and in the diagrams to the standard compass points around the horizon. The position of any object in the sky may be described by its altitude (measured in degrees above the horizon) and its azimuth (measured in degrees from north, 0°, through east, 90°, south, 180°, and west, 270°). Experienced amateurs and professional astronomers also use another system of specifying locations on the celestial sphere, but that need not concern us here, where the simpler method will suffice.

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

Eta Carinae (η Carinae) is one of the most massive and luminous stars known. It is estimated to have a mass between 120 and 150 times that of the Sun, and be between four and five million times as luminous. Jupiter. At the start of the month Jupiter rises in the east-northeast and will be best seen at midnight as it is at closest approach on the 1st/2nd. It will have a magnitude of -2.91 and an angular diameter of 49.5 arc seconds rising to an elevation of ~52 degrees. By month's end, its brightness will have reduced a touch to -2.8 and its angular size to 47.8 arc seconds. Meteorites are conventionally divided into ‘falls’, where the body is seen to fall and the location is therefore known (at least approximately) and ‘finds’, where the object is merely found by chance. There are, of course, far more finds than falls, and the numbers in collections are about 65,000 and 1500, respectively. This month the constellations Lyra and Cygnus are seen almost overhead as darkness falls with their bright stars Vega, in Lyra, and Deneb, in Cygnus, making up the "summer triangle" of bright stars with Altair in the constellation Aquila below. (see sky chart above) Lyra March 2 • After sunset, Venus (mag. -3.9) and Jupiter (mag. -2.1) are close together in the western sky (as seen from London).

The Planets

As with all solar eclipses, view it safely only through proper solar filters. Otherwise, permanent eye damage will result. Oct 10, Nov 9 and Dec 9: Crescent moon meets Venus Some of the most eye-catching sky sights are when the moon glows near the brightest planet, Venus. Three such occasions will occur in fall’s morning sky. As dawn brightens on October 10, November 9 and December 9, look toward the eastern horizon for a dramatic scene. Venus will be unmistakable next to the waning crescent moon. What a sublime sight to start your day! Chart by John Goss/ EarthSky. April from Aprilis (the reason for this one is uncertain, and possibly related to the raising of hogs)

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

This is a great month to observe Jupiter which will be visible for much of the night reaching opposition on the 1st/2nd November. It is now moving up the ecliptic and reaches an elevations of ~52 degrees when crossing the meridian this month. An interesting observation is that the Great Red Spot appears to be diminishing in size. At the beginning of the last century it spanned 40,000 km across but now appears to be only ~16,500 km across - less than half the size. It used to be said that 3 Earths could fit within it, but now it is only one. The shrinking rate appears to be accelerating and observations indicate that it is now reducing in size by ~580 miles per year. Will it eventually disappear? The features seen in the Jovian atmosphere have been changing quite significantly over the last few years - for a while the South Equatorial Belt vanished completely (as seen in Damian's image) but has now returned to its normal wide state. The diagram on right shows the main Jovian features as imaged by the author at the beginning of December 2012. Orion’s Belt points up to the northwest towards Taurus (the Bull) and orange-tinted Aldebaran (α Tauri). Close to Aldebaran, there is a conspicuous ‘V’ of stars, called the Hyades cluster. (Despite appearances, Aldebaran is not part of the cluster.) Farther along, the same line from Orion passes below a bright cluster of stars, the Pleiades, or Seven Sisters. Even the smallest pair of binoculars reveals this as a beautiful group of bluish-white stars. The two most conspicuous of the other stars in Taurus lie directly north of Orion, and form an elongated triangle with Aldebaran. The northernmost, Elnath (β Tauri), was once considered to be part of the constellation of Auriga. February 3 • The Moon forms a nice, almost isosceles, triangle with Pollux and Castor (as seen from Sydney). All the objects in the sky (including the Sun, Moon, and stars) appear to lie at some indeterminate distance on a large sphere, centred on the Earth. This celestial sphere has various reference points and features that are related to those of the Earth. If the Earth’s rotational axis is extended, for example, it points to the North and South Celestial Poles, which are thus in line with the North and South Poles on Earth. As shown in the diagrams, the altitude of the celestial pole is equal to the observer’s latitude, whether in the north or south. Similarly, the celestial equator lies in the same plane as the Earth’s equator, and divides the sky into northern and southern hemispheres.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). There are three different effects that common ideas associate with the equinoxes: One meteorological, and two astronomical. There are strong beliefs in ‘equinoctial gales’, ‘equinoctial tides’ and ‘equinoctial aurorae’. It is often thought that gales are more frequent and strongest at the equinoxes, particularly at the (northern) autumnal equinox. In fact, there are most gale-force winds around the time of the winter solstice in late December and early January. The concept has probably arisen because after the quiet period of summer, depressions, with their accompanying winds, tend to move south and bring high winds to the British Isles. On 13 March 1989 a major geomagnetic storm created a nine-hour disruption of Hydro-Quebec’s electricity transmission system. The accompanying aurorae could be seen as far south as Texas and Florida. The geomagnetic storm was one of a number of incidents during a phase of major solar activity. Both the planets Mars and Uranus end their retrograde motion in January 2023 and revert to direct motion.

Night Sky Almanac 2023: A stargazer’s guide – HarperCollins Night Sky Almanac 2023: A stargazer’s guide – HarperCollins

This way of explaining the motion of the planets, where the circular epicycle was carried around the Earth in a larger circlar orbit prevailed for some years.Mercury is too close to the Sun to be visible this month. It reaches superior conjunction, on the far side of the Sun, on March 17. Venus, in the evening sky, is very bright (mag. -3.9 to -4.0), but too close to the Sun to be readily seen. Mars is initially at magnitude 0.4 in Taurus, but moves into Gemini and fades to mag. 1.0. Jupiter is in Pisces, but is too close to the Sun to be readily visible this month. Saturn is in Aquarius and lies too far into the morning twilight to be seen. Uranus is in Aries at mag. 5.8 and Neptune (mag. 8.0) is in Pisces. That planet comes to superior conjunction on March 15.