22 September 2010, 14:15
mouse93
Southern Cross
A couple of reminders - just for fun and a help to make time to move for some
:How do you know you re looking at the the right one?
Southern Cross has trailing behind it two bright stars known as the pointers, so named since they seem to point to the top of the Cross (they do in fact just miss but ....... ).
Since no other cross has a similar signpost they are a sure indication you have the right one.
These two pointer stars, alpha Centauri and beta Centauri, are again very bright and consequently almost impossible to miss. Beta Centauri is the 11th brightest star in the sky while alpha Centauri is the 3rd brightest star of all.
How to find south using the Southern Cross?
There are three easy ways we can use the Cross to find the South Celestial Pole.
1. Simply extend the long axis of the Cross from the bottom star by 4½ times its length. This won't get you to the pole perfectly but it will get you close enough to be useful.
2. Extend the long axis of the Cross below the Cross for as far as you like. Then, draw another line starting from ½ way between the two pointer stars and at 90 degrees to the line joining them. Where these 2 lines cross is once again roughly the South Celestial Pole.
3. Draw a line between the bright stars Acrux and Achernar (the 9th brightest star in the entire sky). The SCP can be found approximately half way along this line.
Finding the Southern Cross throughout the year
Since most people tend to only look at the stars of an early evening this means that although it is roughly the same time of night each time, the Cross will appear in a different position in the sky depending on the time of year you look.
Source: Southern Cross
P.S. And this Lion is just psycho...
