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Night Sky Almanac 2023: A stargazer’s guide

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The celestial sphere appears to rotate about an invisible axis, running between the north and south celestial poles. The location (i.e., the altitude) of the celestial poles depends entirely on the observer’s position on Earth or, more specifically, their latitude. The highly distinctive (and widely recognized) constellation of Ursa Major with the distinctive asterism of the Plough (or Big Dipper) is now ‘upside down’ and near the zenith for observers in the far north, for whom it is particularly difficult to observe. At this time of year, it is high in the sky for anyone north of the equator. Only observers farther towards the south will find it lower down towards their northern horizon and reasonably easy to see. However, at 30°S, even the seven stars making up the main, easily recognized portion of the constellation are too low to be visible. The principal astronomical event in April is the hybrid eclipse of April 20, with maximum eclipse over Indonesia. Such hybrid eclipses are unusual, because totality is extremely short. In this case the duration of totality is just 1 minute 16 seconds. Only for this short time is the Moon close enough to the Earth to completely cover the disc of the Sun. Because of the curvature of the Earth, the distance is sufficiently great for the eclipse to appear as annular both before and after totality.

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

The Japanese spacecraft Hayabusa 2 obtained the first sample of asteroid Ryugu on 21 February 2019.The two stars Dubhe and Merak (α and β Ursae Majoris) are known as the ‘Pointers’, because they indicate the position of Polaris, the Pole Star (α Ursae Minoris), at about a distance of five times their separation. Following this line takes you to the constellation of Ursa Minor, the ‘Little Bear’ or ‘Little Dipper’, where Polaris is at the end of the ‘tail’ or ‘handle’. Farther south, the Milky Way runs diagonally across the sky, and the constellation of Vela straddles the meridian. Slightly farther south is the constellation of Carina, with, to the west, brilliant Canopus (α Carinae), which lies below the constellation of Puppis, which is itself between Vela and Canis Major in the west.

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

Orion is now beginning to sink into the southwest, and the two brightest stars in the sky, Sirius and Canopus (α Carinae), are readily visible to observers at low northern latitudes and, of course, to those who are south of the equator. (Canopus is close to the zenith for those in the far south.) A finder chart for the position of minor planet (2) Pallas, at its opposition. The grey area is shown in more detail on the map below.The months of January and February are probably the best time for seeing the section of the Milky Way that runs in the northern and western sky from Orion and Gemini right through Auriga, Perseus and Cassiopeia, towards Cygnus, low in the north. Although not as readily visible as the denser star clouds of the summer Milky Way, on a clear night so many stars may be seen that even a distinctive constellation such as Cassiopeia, which lies across the Milky Way, is not immediately obvious. There are indeed equinoctial tides, and these tend to be greater in extent than at other times of the year. The effect is well-known and was explained by Isaac Newton in the late-seventeenth century. He explained the effect by stating that the gravitational effect of the Sun is greatest when its declination (here) is at a minimum. It is then acting along a line to the centre of the Earth, and is not offset to north or south. The Sun’s declination is precisely zero when it crosses the celestial equator, and this occurs, twice a year, at the equinoxes. At the equinoxes, the Sun is directly over the Earth’s equator, and thus exerts the greatest influence over the tides. However, the effect is greatest at the equator itself, and is often masked by other effects, such as those caused by atmospheric pressure and winds. Mercury is not easily visible this month. It lies some angular distance from the Sun but, as the evening ecliptic this month is at a very shallow angle, it cannot be seen in the Sun's glare.

Night Sky for August 2023: Planets, Stars, and the Moon Night Sky for August 2023: Planets, Stars, and the Moon

Ursa Minor, also with seven main stars, one of which is Polaris, the Pole Star, and the long constellation of Draco that winds around the Pole, are readily visible for anyone in the northern hemisphere, although, of course, Polaris is right on the horizon for anyone at the equator, and thus always lost to sight. Cepheus is near the meridian to the north, with Cassiopeia, to its west beginning to turn and resume its ‘W’ shape. The constellation of Andromeda is now diving down into the northwestern sky. In the east, beyond Alkaid (η Ursae Majoris), the final star in the ‘tail’ of Ursa Major, lies the top of Boötes. Farther to the south, most of Hercules and the ‘Keystone’ shape that forms the major portion of the body is visible. At the equinox in March and again, in September, the Sun rises due east and sets due west. In theory, but not in practice, day and night are of equal length (see here). At the equinoxes, the Earth’s axis is exactly at right angles to the Earth–Sun line, and the Earth is neither tilted towards, nor away from the Sun.Beyond the Milky Way, Perseus and Cassiopeia, the constellation of Andromeda is beginning to be lost in the northwestern sky. This ebook contains the following accessibility features which, if supported by your device, can be accessed via your ereader/accessibility settings:

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