To get an idea of the difference between Polaris and our Sun, point your binoculars towards Polaris. Yellow circle represents typical field of view for low power binoculars, such as 10X50. If you put our closest star into this group, our Sun – remember, it is just 8 light minutes from us – in absolute magnitude it would be by far the dimmest of this group – absolute magnitude 4.9! So while Polaris doesn’t look all that bright, it really is a very bright star! Another way to think about this is if you move our Sun out to where Polaris is, it would be about magnitude 10! You would need binoculars or a telescope to see it!Ĭlick image for larger view of this chart. But sometimes it only appears to be very bright because it is very close to us. So sometimes a star is very bright because it’s – well, very bright. In absolute magnitude – the brightness we give to a star if they are all shining from the same distance – these four stars line up this way:Īnd those absolute magnitudes also reflect their order in distance from us. Remember, that the lower the magnitude number, the brighter the star. So which is really the brightest star of these four? Are you ready for this? Polaris! That’s right – if you put all four stars at the same distance, Polaris would appear to be the brightest. And yes, you’re right – they are NOT really as “simple as one, two, three” – on the magnitude scale they are as simple as zero, one, two – but that doesn’t sound as good! (Vega and Capella are zero Spica is magnitude one, and Polaris, magnitude two.) Good luck on telling the difference! This month, if you look north 90 minutes after sunset, you may think Capella is a bit brighter actually – but if it appears that way it will be because it’s a bit higher in the sky and thus is not dimmed by having to fight its way through as much of our atmosphere as Vega is doing at the moment. (To be precise it’s magnitude 2.02.) Vega and Capella are extremely close to magnitude 0. A distinction of Polaris is, as Spica defines magnitude 1, Polaris defines magnitude 2. (That’s on our chart for the east.) One distinction of Spica is that it’s as close to being magnitude 1 as any star gets. First, in the eastern sky in May you meet Spica. That doesn’t mean Polaris is a slouch, though. Polaris, our North Star, is number 48! As simple as one, two, three! When you look at a list of the brightest stars, Vega is number 5 and Capella number 6. Quite bright, but it can’t hold a candle to Capella and Vega. But when it comes to brightness, it’s in the same league as the stars in the Big Dipper. So it serves anyone trying to find true north as a very good guide. It isn’t even close! It is bright, but its fame comes because it’s very, very close to where the axis of the Earth points to the north celestial pole. New star watchers frequently assume the North Star, Polaris, will be the brightest star in the sky. (See “Look East!” for more about Vega.) As a bonus we also have the twin guidepost stars, Castor and Pollux, making their way into the northern sky high above Capella. In May the northeast is dominated by a star that is almost Capella’s twin in brightness, Vega, a guidepost star we introduce in May. To the northwest is Capella, a star we first met when it rose in the northeast in November. If you have been learning your guidepost stars as they rise in the East, you won’t be surprised by the two bright stars which flank – and outshine – our pole star in May. Polaris is not nearly as dim as it looks! Is the North Star – Polaris – our brightest star? No! And it certainly won’t look that way this month as it shares the northern sky with two very bright stars. (Developed from Starry Nights Pro screen shot.)Ĭlick here to download a printer-friendly version of this chart.
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