![]() ![]() Blue stars are the hottest, followed by white, yellow and orange, and then finally red stars are the coolest. We can get a rough idea of a star's temperature based on its color. Hot stars tend to produce more light than cooler ones. There's one other key factor that makes some stars brighter than others, and that's their temperature. This allowed the system to be extended to the fractional and negative numbers that we see today. By the 19th century astronomers needed a more precise scale, so they defined magnitude 2 as 2.5 times fainter than magnitude 1, magnitude 3 as 2.5 times fainter than that, and so on. The system originated in the ancient world when people called the very brightest stars "first magnitude", the next brightest "second magnitude" and so on. The brightness of stars is usually expressed in terms of a "magnitude" value, and - confusingly - this number actually gets bigger for fainter stars. ![]() Not surprisingly, a giant star will be much brighter than a main sequence star seen at the same distance. Our own sun is in the prime of its life - called the "main sequence" of stellar evolution - but stars that are further advanced in their life cycles can grow to giant proportions. At the time the chart is made, there are two very bright planets in the sky, Jupiter in Pisces and Mars in Taurus.A second reason for differences in brightness is that some stars are larger than others. It’s not a constellation, but it’s easy to identify. Overhead we find Perseus, followed by Auriga, with the bright star Capella. To the west we see the square of Pegasus approaching sunset, followed by Andromeda. It is the star Procyon in the constellation Canis Minor. From the “belt” towards Betelgeuse go towards Gemini, Sirius, Procyon and the star in the left-south corner of Orion, Betelgeuse, form a triangle called the “winter triangle”. To the left of Sirius, about the same height as the stars of Orion, is a bright star with three more smaller in brightness above. Use Orion’s belt to find other stars in its extension in the lower left you will come across the star Sirius, and in the upper right you will come across Aldebaran in Taurus. It is Sirius, the brightest star in the sky, in the constellation Canis Major.In the upper right are three other bright stars, arranged in a straight line, which are part of the constellation Orion.If you look closely you will see that they are framed by four other stars, all tracing the shape of Orion the hunter.The two brightest stars in Orion are Betelgeuse and Rigel, to the upper left and lower right of the belt. It reaches high in the sky, almost overhead, around 9 pm, and sets around 5 am. On January 2, Mercury was at its shortest distance from the Sun, at 46 million km. On January 4, the Earth is at its shortest distance from the Sun (perihelion), 147 million km away. On January 7, Mercury is opposite the Sun.ĭuring the winter months, a very bright star can be seen towards the southern horizon. ![]() It is visible almost all night and is very bright. You find it towards the east, just as it is getting dark. Mars looks as good as it did in December. It is Jupiter, 800 million km away from us, another world, totally different from ours and much bigger. Jupiter is high in the sky just after dusk and sets around 10:30 p.m., so you have plenty of time to see it.Īround 7pm look for a bright ‘star’ high in the sky and show it to your children and neighbours. The two planets will approach each other between January 21 and 23. Look at Venus and then at the top left where a non-blinking star should be seen. Saturn is in the same direction as Venus, but is much less bright. The period of good visibility will start in late winter and last until summer. Even though it can’t yet be seen in a night sky, Venus is easily distinguishable even when the sky is still bright. Look to the southwest near the horizon at about 5 pm (but no later than 6 pm) and you will see Venus as a bright star. At the moment it is far from us, but every day it is closer and can be seen better in the sky. In the evening, 30 minutes after sunset, in the same direction, Venus is visible. The Moon passes by Mars on the evenings of January 2, 3 and 4. On January 6th and 7th the Moon will rise as the Sun sets and set as the Sun rises. The Full Moon will occur on January 7 (at 1:08). Sirius is the brightest star visible in the sky during this period, according to the astronomical calendar published by the Admiral Vasile Urseanu Observatory. Immediately after sunset, Venus and Saturn can be seen, and Jupiter and Mars remain in the sky for several hours. In the evening sky, one can see four planets, Venus, Saturn, Jupiter and Mars. ![]()
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