Jupiter Tonight

Tonight, at about 9 PM, you can see Jupiter, our solar system's largest planet, rising up in the east.  As the night goes on, Jupiter will rise higher and higher, reaching it's zenith at about 3 AM and then it will start descending toward the west, getting drowned out by the rising Sun's light before it reaches the western horizon.

Jupiter will be almost directly east at 9 PM and will be incredibly bright.  If you read my my previous posts about finding the North Star, you already know how to find north.  If you didn't read that post, go on and do it now…it's okay, I'll wait.

Done?

Good, moving on…

Click for Larger view (Image by Stellarium)

If you are facing North, then Jupiter will be directly to your right.  Not to your right on a diagonal cherubs, directly to your right.  Low in the northeast, there is a very bright star that you might confuse with Jupiter; its name is Capella, and is the brightest star in the constellation of Auriga, the Charioteer.  Here is how you tell the difference between the two.  First, Jupiter will be brighter than Capella, and secondly Capella twinkles, Jupiter does not.  That is the easiest way to tell the difference between stars and planets in the sky––stars twinkle, planets do not twinkle; that's why you never hear preschoolers singing Twinkle, Twinkle Little Planet.  


The reason why stars twinkle and planets do not is because the stars (with the exception of the Sun) are so much farther away.  They send out an incredible amount of light in every conceivable direction, but the amount that reaches us here on the Earth is very minimal.  The gases in our atmosphere push that light around––warm air, more than cold air––and we see that as twinkling.  The planets on the other hand reflect sunlight, so the light doesn't have to travel so far to hit your eyes and therefore, more of the light is reaching them.  So, while individual rays of light may be getting scattered, the other rays that are hitting your eyes compensate for them and the overall effect is a lack of twinkling.

Interestingly enough, stars do not twinkle on the moon.  The moon doesn't really have any atmosphere to speak of, so there is nothing to bend and push the starlight around.

Who knew?

Good luck finding Jupiter tonight, and if you don't see it, just wait an hour or so, it's possible that trees or houses are blocking it from your view.  Either that, or it's cloudy and you won't be able to see it anyway, so go inside and watch The Big Bang Theory (my new favorite show, yeah I know I am late to the party).

Good luck and have fun looking up!

The Summer Triangle; or the Autumn Anachronism

Ready to have the easiest time ever finding something in the sky?  Tonight, at 9 PM, go outside and look straight up while facing west.  Near the zenith (top) of the sky in the northern latitudes is a very bright star called Deneb.  It is the brightest star in the constellation of Cygnus, the Swan.  Down and to the west of Deneb is an incredibly bright star.  This star is Vega and tonight, it will be high up in the western sky.  Vega is the brightest star in the constellation of Lyra, the Lyre.  To the left of Vega high in the SSW sky is yet another bright star; this one is called Altair and it is the brightest star in the constellation Aquila, the Eagle.

Facing West, Looking up (Image created using Stellarium)

Don't worry about finding the constellations that house these three stars right now, just locate the stars themselves; it shouldn't be too hard, they are the brightest stars in that area of the sky tonight.  The most difficult to locate will be Altair because it is not as close to Deneb and Vega as those two stars are to each other.  Once you have located those three stars, pat yourself on the back, you have just found the asterism known as the Summer Triangle.  To tell the truth, it's name is not very accurate because you can see it well into November, but "The Summer-Well-Into-Autumn-Triangle" just didn't roll off the tongue very well, so, the Summer Triangle it is.

The reason why I wanted to point out the Summer Triangle to you is because this is a different sort of an asterism than what we have encountered so far.  The other asterisms we have seen (the Big Dipper, the Little Dipper) were recognizable patterns of stars within constellations; but the Summer Triangle is a recognizable pattern made up of stars from different constellations.  So, an asterism is not bound by the borders of constellations but is simply a recognizable pattern of stars in the sky that is not a constellation.  We will see more of this as autumn turns to winter.

Have fun finding the Summer Triangle!  Next time, we are going to talk about the difference between stars and planets in the sky and we will even locate Jupiter in the sky…can you stand the suspense?!  

Until then, be well and keep looking up!