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Bright objects in the east and the west ..

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  • 05-05-2018 10:11pm
    #1
    CamperMan
    Registered Users Posts: 1,835 ✭✭✭


    looking at the sky in the last couple of nights there have been large bright "stars" in the east and the west, much bigger and brighter than the average star, never seen them before either and I am frequently looking up at the sky at night

    any ideas of what I am looking at?


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    #2
    Standard Toaster
    Registered Users Posts: 10,264 ✭✭✭✭Standard Toaster


    Likely Jupiter in the east and Venus in the west.
    Venus would be setting around dusk while Jupiter would only be starting to be visable about the same time, give or take. I was watching them earlier this eve :)


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    #3
    ps200306
    Registered Users Posts: 1,611 ✭✭✭ps200306


    Yep. Venus is a blazingly bright magnitude -4 in the west after sunset. If you're looking soon after that, the bright first star to appear is Arcturus high up in the east. Jupiter appears later on, very visible after midnight, about magnitude -2.5. So depends what time you are looking, but you can always tell the difference between a star and a planet (even apart from brightness) -- Arcturus will be twinkling but Jupiter will be very steady.


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    #4
    moneymore
    Closed Accounts Posts: 22 ✭moneymore


    Is anyone seeing the extremely bright 'blue star' in the west of the sky tonight? Can someone please explain what it is?


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    #5
    ps200306
    Registered Users Posts: 1,611 ✭✭✭ps200306


    moneymore wrote: »
    Is anyone seeing the extremely bright 'blue star' in the west of the sky tonight? Can someone please explain what it is?
    What time, how high above the horizon? (measured in "fingers" like this):

    Mlfo5ug.jpg?1


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    #6
    moneymore
    Closed Accounts Posts: 22 ✭moneymore


    ps200306 wrote: »
    What time, how high above the horizon? (measured in "fingers" like this):

    Mlfo5ug.jpg?1

    Right now, roughly 6 fingers


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    #7
    ps200306
    Registered Users Posts: 1,611 ✭✭✭ps200306


    That's Regulus in Leo, a hot blue-white star (the astronomers would call it a type B, surface temperature around 11-12,000 K, about twice as hot as the Sun).


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    #8
    moneymore
    Closed Accounts Posts: 22 ✭moneymore


    ps200306 wrote: »
    That's Regulus in Leo, a hot blue-white star (the astronomers would call it a type B, surface temperature around 25,000 K).

    I've never seen a star that blue in the sky before it's basically noen, you'd swear it's a light on top of a mast only for the height! where I am there's no other star visible in the sky tonight!


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    #9
    ps200306
    Registered Users Posts: 1,611 ✭✭✭ps200306


    Yeah, its pretty neat. I got the temperature wrong ... turns out it's a late B type, corrected above. The early B types and O types are the real hotties. They're what make the arms of spiral galaxies blue, like this:

    z028c59.jpg?1

    They live fast and die young though. The very hottest come and go in just a few million years. The hot B types might last 15 or 20 million. Regulus, being on the cooler end might last a couple of hundred million. But it'll still die a young pup compared to our Sun which will still only be in young middle age when Regulus is a distant memory.


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