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Karina
2003-Dec-18, 04:45 PM
My husband and I were arguing about what might be the brightest, most light emitting element in our nightsky, he claims it is Venus, but I believe it is the Dogstar/Northstar/Sirius.

I seem to remember the notion that not all constellations and planets are visible at all times, at all latitudes and altitudes, like for instance Orion might only be in the nightsky in my native Denmark six or eight months. And planets are increasingly hard to spot because we only see the reflected light of their surface from our sun?

But is there a general answer, that might resolve this arguement?

Thank you for your time.


Karina



-- May the best man or woman win, (and may that be me) --

Littlemews
2003-Dec-18, 06:37 PM
Too confuse....I always thought that Sirius is the brightess star in the nightsky after sunset...I mean u only can see Venus during evening like 6 PM - 7 PM, so after 6PM - 7PM, Venus become invisible, so people who living in western cant see it anymore, excpet those people who living in the northern, such as Australia and Bolivia, they can see it....

jimmy
2003-Dec-18, 06:58 PM
From brightest are: The sun, full moon, Venus, Jupiter (-3 mag.), Mars ( varies from -3 to +2); then Sirius, etc.
From my house -6 GMT, I can see(with the unaided eye) Mars, in the western sky, Saturn almost straight up, and Jupiter just rising in the east all at the same time. Last week, Mercury was visible for a bout a half hour.

Karina
2003-Dec-18, 07:09 PM
Hey wait, now I am confused...So Venus IS brighter then Sirius?
Is that true if seen anywhere in the world?

TheThorn
2003-Dec-18, 08:25 PM
Venus varies in brightness, but it is normally brighter than Sirius. You said you live in Denmark. Go out tonight just after sunset and look west. That very bright star you see just above the horizon is Venus. In the south east, you'll see another bright star - that one's Sirius. Compare them for yourself. Venus is quite a bit brighter.

Littlemews
2003-Dec-18, 09:23 PM
:lol: I would said all the planets and stars are the same amount the brightess, cuz they just too far away and we cant see it ><

After Sunset between 6 pm to 7 or 8 pm, Venus is the brightess star in the nightsky.

After 7,8 or 9 pm, Sirius become the brightess star in the nightsky :huh:

Karina
2003-Dec-18, 10:33 PM
:D Hey Guys I have been checking in all day, and I appreciate your answers, but despite wanting to believe that I&#39;m right, I am still not sure. I am originally from Denmark but currently lives on the eastcoast of USA.

And not to split hairs, but isn&#39;t it more correct to describe venus as a planet as opposed to a star on the nightsky?

Avav don&#39;t hit me ;) ...

Right now I am on the westcoast of Florida, where can I find Venus and the northstar/sirius on the sky...?

Thank you all...

karina

kashi
2003-Dec-18, 11:20 PM
Brightness and "most light emitting" are too completely different things. Planets emit no light of there own, and are only bright because of the light they reflect off the sun.

The brightest object in the night sky is the moon. After that I believe littlemews is correct. There are heaps of bright objects, let&#39;s not forget the international space station&#33;

Kashi

Kashi

Littlemews
2003-Dec-19, 12:26 AM
U can see Venus at 9 AM (Raise from the southeast sky, 119") to 7 PM (Sets on the southwest sky 249")

For Sirius : Start from 7 pm, East(Visible Azimuth angle 112") all the way to west(Sets Azimuth angle 249")

Northern Star : I believe its Northeast at azimuth angle 39" at 6 AM and sets at 11 pm, northwest at azimuth angle 321"

jimmy
2003-Dec-19, 12:53 AM
The information I gave you is from an astronomy book, that&#39;s all I can say.
Do you know how to find Sirius? Find the constellation Orion, then follow his belt downward or to the ESE. It&#39;ll rise in Florida about 7:45 local time. Later, about midnight it will be almost overhead, look to the eastern horizon again and out will come Jupiter. If you&#39;re up at about 2AM you&#39;ll see how it is brighter than Sirius, though not that much. Also, at about midnight look toward the west and Mars will be setting.

Littlemews
2003-Dec-19, 02:19 AM
It easy to figure out where and when the star can be ound by using the SkyGazer porgeam :lol:

TheThorn
2003-Dec-19, 02:20 AM
You&#39;re right, it was technically not correct for me to refer to Venus as a "Star" - but if you don&#39;t know that it&#39;s a planet, it pretty much looks like a very bright star (except that it doesn&#39;t twinkle).

And LittleMews is right too, you can see it any time between 9 am and 7 pm. That&#39;s right, it&#39;s so bright that you can see it in the daytime (I have), but you have to know exactly where to look. After the sun goes down, it&#39;s so bright that if you face west you can&#39;t miss it.

LittleMews is also right about Sirius. It rises in the south east just about the time Venus sets, and moves across the southern sky through the night. In a couple of weeks Venus will have moved enough so that they will both be well above the horizon at the same time and you can easily compare them to each other.

You seem to be under the impression that the North Star is Sirius. It&#39;s not. The North Star (Polaris) isn&#39;t really all that bright. But it is always due North, and there are no brighter stars nearby, so it&#39;s not hard to identify. And somehow LittleMews got that one wrong - it never rises or sets. It&#39;s always due North of any location in the Northern Hemisphere at any time of night in any season. It&#39;s elevation above the horizon is equal to your latitude.

jimmy
2003-Dec-19, 02:34 AM
Is that program expensive, littlemews?

Littlemews
2003-Dec-19, 02:40 AM
No :lol: it free, >< Demo version

For Windows:
http://www.carinasoft.com/win_demo.html

For Mac
http://www.carinasoft.com/mac_demo.html

Dave Mitsky
2003-Dec-19, 08:48 PM
Originally posted by TheThorn@Dec 18 2003, 08:25 PM
Venus varies in brightness, but it is normally brighter than Sirius. You said you live in Denmark. Go out tonight just after sunset and look west. That very bright star you see just above the horizon is Venus. In the south east, you&#39;ll see another bright star - that one&#39;s Sirius. Compare them for yourself. Venus is quite a bit brighter.
Venus and Jupiter are both always brighter than Sirius.

Dave Mitsky

jimmy
2003-Dec-20, 04:49 AM
Thanks Dave, I tried to tell them&#33;

TheThorn
2003-Dec-20, 05:21 PM
Hi Dave.


" Venus and Jupiter are both always brighter than Sirius."


Technically....

When Venus is at superior conjunction, we&#39;re looking at the dark side of the planet. At that point it is dimmer than Sirius. Of course it is also very close to the sun, so we can&#39;t see it naked eye anyway.

Consider the extreme case - Venus in transit across the face of the sun. From our point of view, none of the planet is lit, so it would be a very dim object, even if the sun weren&#39;t blinding us by being directly behind it.

OTOH, if it is far enough away from the sun to be visible in the evening or morning sky, it is brighter than Sirius all right.

Now, earlier, I got corrected for being technically incorrect when I referred to Venus as the bright star just above the western horizon <G>.

Littlemews
2003-Dec-20, 06:50 PM
so it depends on what time you observer the sky as to prove that Sirius is the brightess star in the nightsky right? Yea I agree with Dave Mitsky, both Venus and JUpiter are the brightess object in the nightsky, but after 12 AM, Sirius still in the sky, but cant see Venus and Jupiter anymore. Therefore, Sirius is the brightess at that time....till Jupiter raise at 11 PM on the eastern Horizon, then Venus... :)

Karina
2003-Dec-20, 11:18 PM
Thank you TheThorn and LittleMew and everybody else for helping me with this subject. Being quite dim about astronomy, (besides being able to locate Orion on the nightsky, and of course the obvoius like the moon) It seems that there was well enough reason for the dispute. I am going to print out all of the replies and show them to my husband , who surely will argue that he, of course, was right. (weather that might be the truth or not, I shall give him the satisfaction)

But i learned something else from this discussion, when somebody pointed out that the moon surely is the brightest element in our nightsky. How could I forget, the most obvious knowledge, aquired as one of the first lessons as a human being. Right in front of my nose.

So we were both wrong, technically.

And I appreciate your time and knowledge tremendously. :D

In regards to planets not emitting light, my mistake. ;)

Karina

Dave Mitsky
2003-Dec-27, 11:59 PM
Originally posted by TheThorn@Dec 20 2003, 05:21 PM
Hi Dave.


" Venus and Jupiter are both always brighter than Sirius."


Technically....

When Venus is at superior conjunction, we&#39;re looking at the dark side of the planet. At that point it is dimmer than Sirius. Of course it is also very close to the sun, so we can&#39;t see it naked eye anyway.

Consider the extreme case - Venus in transit across the face of the sun. From our point of view, none of the planet is lit, so it would be a very dim object, even if the sun weren&#39;t blinding us by being directly behind it.

OTOH, if it is far enough away from the sun to be visible in the evening or morning sky, it is brighter than Sirius all right.

Now, earlier, I got corrected for being technically incorrect when I referred to Venus as the bright star just above the western horizon <G>.
I could argue that my answer is more than just technically correct given that it was offered in response to a query on naked-eye observing. It&#39;s pretty hard to observe Venus around inferior or superior conjunction without a telescope. In the future I&#39;ll endeavor to qualify my answers to the ultimate degree possible.

Venus is actually at its brightest (around -4.7 magnitude) when it is approximately 25% illuminated. It is the only planet that is brightest at a crescent phase. Minimum brilliancy comes at superior conjunction (-3.9 magnitude).

Dave Mitsky

Planetwatcher
2003-Dec-28, 03:11 AM
Like others have said, planets are generally the brightest objects after the Moon.
Though they fluctuate, they are in order of brightness Venus, Jupiter, Mars, Saturn, Mercury, Uranus, Neptune, and finally Pluto.

Venus is always brighter then any star, and so is Jupiter most of the time, As was Mars last summer and when it is closest to Earth. Saturn comes close but doesn&#39;t quite ever become as bright as Sirus. At times Mars will be dimmer then Saturn, and Mercury brighter then Saturn. Uranus is seldom barely seeable with the naked eye. Neptune and Pluto can not ever be seen without optical aids

As for the stars, the 5 brightest in order are Sirus, Alpha Centauri, Procyon, Tau Ceti, and Epsolin Eridani. But I don&#39;t think there is too many places where you can see all 5. Sirus, and Procyon are in the northern hemoshere. Alpha Centauri, and Tau Ceti are in the southern hemoshere. Epsolin Eridani can be seen from both up to middle lattitudes.

Dave Mitsky
2003-Dec-28, 07:08 AM
Planetwatcher,

Since Jupiter has a minimum magnitude of about -1.7, it is always brighter than Sirius.

Your list of bright stars is seriously in need of revision. The five brightest stars (other than the sun) are Sirius, Canopus, Alpha Centauri, Arcturus, and Vega. Tau Ceti and Epsilon Eridani are not even second magnitude stars.

http://www.astro.wisc.edu/~dolan/constella.../brightest.html (http://www.astro.wisc.edu/~dolan/constellations/extra/brightest.html)

Dave Mitsky

Littlemews
2003-Dec-28, 09:33 PM
Compare to the surface temperature of all the Brightess star : Sirius, Venus, Sun and Northern Cross

Sirius : About 10000 K
Venus : About 6000 K
Sun : About 6000 K
Northern Cross : About 9000 K I believe
Moon : About 260 K
Jupiter : 102 K
Mars : 224 K

Since all brightess stars are too far away, therefore Sun is the rightess, then Moon, Venus, Mars, Jutpter, Sirius and Northern Cross....(I guess)

jimmy
2003-Dec-29, 04:44 AM
Little mews,
don&#39;t forget that Mars is variable and is sometimes brighter than Sirius.
See Dave Mitsky&#39;s link to the brightest stars.

Littlemews
2003-Dec-29, 05:00 AM
Oh :lol: and Mars

jimmy
2003-Dec-29, 05:02 AM
:lol:

Planetwatcher
2003-Dec-29, 05:47 AM
Since Jupiter has a minimum magnitude of about -1.7, it is always brighter than Sirius. Your list of bright stars is seriously in need of revision. The five brightest stars (other than the sun) are Sirius, Canopus, Alpha Centauri, Arcturus, and Vega. Tau Ceti and Epsilon Eridani are not even second magnitude stars.

I took another look at my source. It was specificly listing among the nearest 25 stars to us. Which does not include Canopus, and Arcturus which are much farther.

So the list I have is accurate for it&#39;s purpose, but I took it out of context. Over all David Mitsky is correct again.