Irene Worthington Baron

HOW-MANY-STARS-CAN-YOU-SEE?

How many stars can you see in the night sky?

Want to count the night stars to find out? If so, plan ahead and obtain a hand held counter so you can just click off each star you see while making your sky survey. 

 

It will take some time, so it might be a good idea to prepare a place to gaze at the sky. Perhaps a reclining lawn chair? Why not have something non-alcoholic to drink? (You don’t want to lose count or lose your place!) You might even want to have some popcorn available for your unencumbered hand. You can chew to the clicks of stars being counted to set up a personal rhythm base!  :-)

Then, sit down and begin counting on a clear, light pollution-free night.  How many stars do you think you’ll see? Millions?

 Guess again.  Because human eyes don’t have a time exposure apparatus like a good camera, you won’t be able to see stars that are outside your visual range.  Star brightness is measured on a magnitude scale.  Most humans can only see the brightest stars. 

 We use the terms “apparent magnitude” and “absolute magnitude” when discussing the brightness of stars.  The apparent magnitude is how bright a star would appear to our naked eye here on Earth. Absolute magnitude is how stars would appear if placed side by side at the same distance.

 For example, if you saw two stars in the sky side by side, one may actually be hundreds of times brighter than the other. However, due to its further distance, it appears dim and as bright as a closer and much dimmer star.

 Using the magnitude scale, we can see stars with a magnitude of 6 or brighter.  The smaller the number, the brighter the object. The Sun would be a -26,74 while the full Moon is -12.74..

 Sirius is the brightest star in our night sky with a magnitude of -1.46. It is 8.6 light years (ly) distant.  It used to be a red star but has changed in written history. Astronomers are not sure what created that change. WHAT? You thought all stars were white?  Look again. Stars are red, yellow, white, blue-white and blue.

 To see an easily recognizable red star, find the constellation Orion in the current morning sky. The star making up the left top corner of Orion is the red star Betelgeuse. This star of 640-light years distant has a magnitude of .42.

 My astronomy professor pronounced that bright Orion star “bay-tell-geese”. Strange name, isn’t it?  I always thought so until I lived in Thailand 4-years and learned about the Betel nut.  It’s a mild narcotic when chewed.  You can always tell of those that imbibe Betel, for their teeth, gums and all the insides of their mouth becomes stained with the blood red of the nut!  When they smile, they look like a creature from a horror movie. 

 The seven “sister” stars of the Pleiades Cluster are another easily seen example. A time exposure image of that star group will show hundreds of stars. 

 So … how many will YOU see if you could count all those from your location?   Believe it or not, you’ll see only a little over 2,000 with your human eyes.  Surprising, isn’t it?  At first glance, you’d expect there to be many more visible from any site on Earth.

The latest news in astronomy that I have really enjoyed is, for the first time, 84,000,000 stars of the Milky Way were captured in one image.  You can see that image at this link:

http://www.foxnews.com/science/2012/10/24/amazing-photo-captures-84-million-stars-in-our-milky-way-galaxy/

 Is that all the stars contained within our galaxy of the Milky Way? No. That’s just one view.  Had the camera been on the view longer, perhaps more stars would have emerged into the image. What is phenomenal is the number of stars captured in that one image.  You can also see some of the dark matter which is not luminous. 

 Don’t you love astronomy?  :-)

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