How to See the Dog Star
Sirius is the sky’s brightest star. It’s nearly 3-and-a-half times brighter than Arcturus, the next-brightest star easily visible from northern latitudes. Most people notice Sirius in the southeast – south – or southwest on evenings from winter to mid-spring. It’s also fun to spot Sirius as it ascends in the east before dawn on late summer mornings.
Although white to blue white in color, it wouldn’t be unreasonable to refer to Sirius as a rainbow star, as it often flickers with many colors.
Image Credit: Yuuji Kitahara
The brightness, twinkling and color changes sometimes prompt first-time observers to report Sirius as a UFO. But these changes have nothing to do with Sirius. Rather, they are the result of variations in Earth’s atmosphere. The light from Sirius, which always appears fairly low in the sky from the mid-north latitudes, passes through a long column of air before it reaches our eyes. Changes in density and temperature of this air affect the light and cause the behavior we see. This happens for other stars, too, but it is more noticeable for Sirius because it is so bright, and because it appears low in the sky.
From the mid-northern latitudes such as most of the U.S., Sirius rises in the southeast, arcs across the southern sky, and sets in the southwest. In December, you’ll find Sirius rising in mid-evening. By mid-April, Sirius is setting in the southwest in mid-evening. Sirius is always easy to find. It’s the sky’s brightest star! Plus, anyone familiar with the constellation Orion can simply draw a line through Orion’s Belt, to the left. This line will point to Sirius, which is roughly 8 times as far from the Belt as the Belt is wide.
History and Myth
Sirius has been known since ancient times, and its name signified its nature as “scorching” or “sparkling.” It was associated with the Egyptian god Osiris and other gods. Ancient Egyptians noted that Sirius rose just before the sun each year immediately prior to the annual flooding of the Nile River. Although the floods could bring destruction, they also brought new soil and new life. Fittingly, Osiris, whom Sirius may have represented, was a god of life, death, fertility and rebirth of plant life along the Nile.
Sirius is also well known as the Dog Star, because it is the chief star in the constellation Canis Major, the Big Dog. Have you ever heard anyone speak of the dog days of summer? That phrase recalls Sirius’ role in predicting the summertime Nile floods.
In India, Sirius is sometimes known as Svana, the dog of Prince Yudhistira. The prince and his four brothers, along with Svana, set out on a long and arduous journey to find the kingdom of heaven. However, one by one the brothers all abandoned the search until only Yudhistira and Svana were left. At long last they came to the gates of heaven. The gatekeeper, Lord Indra, welcomed the prince but denied Svana entrance. Yudhistira was aghast and told Lord Indra that he could not forsake his good and faithful servant and friend. His brothers, Yudhistira told the Lord, had abandoned the journey to heaven to follow their hearts’ desires. But Svana, who had given his heart freely, chose to follow none but Yudhistira. The prince told the Lord that without his dog, he would forsake even heaven. This is what Lord Indra had wanted to hear, and then he welcomed both the prince and the dog through the gates of heaven.
Science
Magnitude is a star’s brightness expressed by a number. The smaller the number, the brighter the star. The visual magnitude of Sirius is -1.44, lower than any other star. It is 3.5 times brighter than Arcturus in Bootes, the next brightest star easily visible from the northern hemisphere. There are brighter stars in terms of actual energy and light output, but they are farther away and hence dimmer. Normally, the only objects that outshine Sirius in our heavens are the sun, moon, Venus, Jupiter, Mars and Mercury (and usually Sirius outshines the latter two!).
The next brightest star (Canopus) after Sirius, and the closest major star (Alpha Centauri) are both too far south in the sky to be easily seen from mid-north latitudes.
At 8.6 light-years distance, Sirius is one of the nearest stars to us after the sun. (A light year is nearly 6 trillion miles!) In fact it is the nearest star easily visible to the unaided eye from most of the northern hemisphere. Classified by astronomers as an “A” type star, it is much hotter than our sun, with about surface about 17,000 degrees F (the sun is about 10,000 degrees F). With slightly more than twice the mass of the sun and just less than twice its diameter, Sirius still puts out 26 times as much energy. It is considered a normal (main sequence) star, meaning that it produces most of its energy by converting hydrogen into helium through nuclear fusion. As mentioned above, Sirius has a small, faint companion star appropriately called “The Pup.” That name signifies youth, but in fact “The Pup” is a dead star called a “white dwarf.” Once a mighty star, today it is an earth-sized ember too faint to be seen without a telescope.
The position of Sirius is RA: 06h 45m 08.9s, dec:-16° 42′ 58″.
thankyouuuuuuuuuuuuuuuuuuuuuuuuuu
and i thought it was venus
Klondyke, Venus is up before dawn too. Sirius is more to the south and higher in the sky. Venus is low in the east, just before dawn breaks.
Thanks for visiting our site,
Deborah
i also did.
Mercury and Venus, being closer to the sun than Earth, will always be on the same side of the sky as the sun. That is, Mercury and Venus will be in the morning sky before dawn or the evening sky after dusk. Never Venus in the East after sunset, for example.
isnt there a brighter star in its absolute magnitude but it appears dimmer because of its distance?
Yes, Mia, you are absolutely right. Sirius, the brightest star in the constellation Canis Major the Big Dog, looks especially bright from Earth because it’s relatively close to us at 8.6 light-years away. However, the tail star of the Big Dog – Aludra (Eta Canis Majoris) – is intrinsically much more luminous than Sirius. Aludra looks dimmer than Sirius because it is so much farther away. The Hipparcos satellite gives a distance of 3200 light-years for Aludra, though this distance can’t be known with certainly. Without doubt, Aludra is a blue supergiant, its luminosity at least tens of thousands of times greater than that of our sun. In contrast, Sirius is only 26 times more luminous than the sun.
Absolute magnitude refers to how bright the star would look at 32.6 light-years away. Here are the absolute magnitudes listed for these stars in the Observer’s Handbook 2009:
Sirius: 1.5
Aludra: -7.5
That makes Aludra 9 times greater than Sirius in absolute magnitude: 1.5 – (-7.5) = 9. At the same distance away, Aludra would shine about 4,000 times more brightly than Sirius.
Bruce
yeah,,but its not the matter of distance,,it is how we saw it from our planet earth,,,
So, visual magnitude is a measurement taken with relation to the earth. Absolute magnitude refers to the actual brightness by fixing a stars’ position to 32.6 light-years away?? Right?
no shit
I mean, visual magnitude is a measurement of a stars’ brightness in relation to the viewer on earth. Absolute magnitude refers to the actual brightness of a star, calculated by “fixing” a stars’ position to 32.6 light-years away?? Right? I live in North Pole, Alaska. I see Sirius very low in the sky. It looks like airplane lights….flickering red and blue… but it stays in the same place . I watch it flicker every clear night opposite the sky from the northern lights..aurora borealis!!
I see that same star from Los Angeles, California
it’s just amazing.
You all are wrong
About 4 weeks ago I noticed a bright white star not too far above the horizon. It persisted in the blue sky after dawn–even after the moon had set, if I remember rightly. Just last night I saw it in the blue sky at evening, when the moon was out but no other stars.
I assumed it was Venus, but maybe it was Sirius?
Thanks.
We are in Sandy Pond, NY on July 3rd looking to the west. At 9:00 PM. a very bright star appeared in the sky – alone and with no others remotely visible. Can you tell us what this star might be? Can’t tell from your description whether it is sirius or not.
Thanks.
In July, Sirius would rise very early in the morning in the east, not the west. My guess would be that you were looking at Venus.
The wave length of a star is greater which is farthest from earth so sirius should be far 4m us
I see the Dog Star, Sirius, over my house for the past few months now. Here is the URL to the video
http://www.youtube.com/watch?v=GatrwHxoBvs
So that’s the brightest star? Hmm I thought it was something else. In any case I’m happy to know what I’ve staring up at for the past few months. I thought it was Jupiter!
Although Sirius apperas to be the brightest star in the sky, it is actually less luminous than Arcturs. Why migh this be true given the apparent colors of these stars.
so why is it called the brightest star anyway,,,????i dont understand,,,pls make ur own explaination.
when I was a kid, my grandfather told me that Venus is the heart of Orion. I’m not really sure about that now. Thinks for the diagram, I’ll be able to find Sirius by following Orion’s belt.
[...] http://earthsky.org/brightest-stars/sirius-the-brightest-star [...]
Thanks for the info… I live in New york Upper manhattan and I see what I think is a star but its sooo bright I mean really bright and its low too Probably the star thats being described here…
asztig ko!! :)))
Glad this website is here. I don’t think I’ve seen that star so clearly as tonight! San francisco, High of 75 today, this evening 65 degrees
Please correct this to say Sirius was considered to be the Goddess ISIS. Because that is the case…this “associated with Osirus & other gods” thing…why be so vague? Why cover up that Sirius was considered to be a Goddess?
Nice to see that even on a scientific website people are engaging in ridiculous ‘paranoid’ accusations of coverups in postings. I don’t want to miss one moment of these people even though I just came here to find out what the heck is in the eastern morning sky. Once again, I am treated to the keystrokes of loons whose fingers are not attached to their brains.
oh Venus, you are so beautiful, you will shine in my heart forever, amen.
What density and temperature changes in the atmosphere cause Sirius too look like a rainbow star? Tonight, from 62 degrees north, all of the stars are twinkling an extra amount, but Sirius espescially looks like its at a disco party!
I wanted to do this thing 4 school cuz its same name as Sirius black on harry potter
Sirius is indeed associated with Isis the Egyptian goddess as she traverses the skies beside Orion which is considered to be Osiris.
I am sure no deception was intended on behalf of the writer.
Why is it so bright?????
I needd to knowww asapp!!
please help!!
ASAPP!!
Hi bruce,
nice explanation about the Aludra. can you explain the posion of sirius, aludra on the universe with respect to sun.
GRM
GRM,
How about An Atlas of the Universe to visually display the positions of the stars relative to our sun? Click at http://www.atlasoftheuniverse.com/index.html
Bruce
Thank you Bruce.
I have a doubt on how the spacecrafts are being stopped at one point? (Example Cassini to Saturn) this cassini has been stopped or change its path in such a way it detatch the huygens to TITAN. please explain me in detail about this last phase of operation.
Regards,
GRM
i live in the panhandle of texas, and i noticed a broght star to the east/southeast. Is it sirius or something else? Cuz im trying to ezplain 2 my mom that its not a UFO.
Bobbie,
What time were you looking? Good chance, though, that it was Sirius! Read more at http://earthsky.org/tonight/good-sky-trick-orions-belt-points-to-starsirius
Bruce
That Sirius is following me..what am I supposed to do?
I live in Amsterdam and tonight around 2130 I notice a bright star low in the sky. It was so much brighter than the other stars with slight flickering of color….I wondered what it was. I got my camera and through my lens it appeared to wavering. How is this possible? Thanks for your information on Sirius.
Awww, looks like I was not able to see it. It seems like many thought is was a UFO.
from UK,Bright star in the east Nov 22nd 2011, is it Sirius, also known as Dog Star, please let me know and put me out of my misery,
Ray D
Should add 8pm GMT
[...] and one of the most luminous stars known, it is nearly 800 light-years away. If it were as close as Sirius, the brightest star visible to the eye (and only about 8.6 light-years away), Rigel would shine [...]
Sirius is also known as Sothis, i.e. the Goddess Aust {Isis}. The ancient Egyptians also called her the Dog Star. I was reading a chapter from The Egyptian Book Of The Dead, Which is also known as The Ancient Egyptian Book Of Life, Chapter LXV 2, the last sentance reads; The legs of Sothis are stablished, and I am born in their state of rest.”
It would take far to much time and space to answer this, but the ‘legs of the Goddess Aust’, are the two moons that Sothis has. Funny thing, we didn’t know Sothis even had moons until 1995, how did the ancient Egyptians know this over six thousand years ago? Also a tribe called the Dogone in Africa knew about these moons thousands of years ago, and without a high powered scope, the only way they can be seen? I hope my spelling is correct, i have a hard time with it.
For ages i thought it might have been something like a drum shaped sattalite ie sun reflecting off of solar panels but this site has cleared it all up for me
Thanks
I remember the first time someone demonstrated a FAX machine to me. I thought they were having me on. I mean they told me that the architectural drawings they were putting on the machine would appear in another office within minutes. Pure magic! Now of course FAX is old hat right? We have progressed very quickly from FAXES. I only bring this up because I think it is the same with Space Travel. Right now it still seems rather magical but one day it is going to be jut accepted the way we immediately accept all the other ‘wonders of the world’ once we are used to them. I think the Dogan tribe in Africa are on to something. It makes sense to me that if we are trying to ‘go out into space’ other planets around other suns have also thought of it and, if they are more advanced than we, have already done so! As Sirius is the closest star to our sun it makes sense hat it is from that solar system that our visitors would travel to our earth (though heavens knows why – if I were a space traveler the last planet I would want to visit is earth where people are bent on slaughtering each other daily. But in any case, forget that last remark. If, for example earth has received visitor from say a planet that rotates around Sirius , then perhps over five thousand years ago this did happen. It could explain the pyramids,, Easter Island, Newgrange in Ireland, Stonehenge in England, etc. All built with stone and all somehow designed with some sort of purpose in mind – something to do with the summer and winter solstice perhaps. Or something to do with astronomy. It would account for the fascination the ancient Egyptians had with Sirius. Perhaps we are in for another visit. I certainly hope so. Maybe this time around they will not only show us how to build even more intriguing monuments – maybe they will teach us how to live in peace.