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sigma octantis.

Discussion in 'General Astronomy Chat' started by kevan hubbard, Jun 19, 2018.

sigma octantis.

Started by kevan hubbard on Jun 19, 2018 at 5:41 PM

2 Replies 1444 Views 1 Likes

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  1. kevan hubbard

    kevan hubbard Well-Known Member

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    kevan hubbard, Jun 19, 2018
    #1
    Anyone ever seen the south pole star naked eye?I was just reading that it has been given an official name,polaris australis. It is of similar brightness to Uranus, 5.47 magnitude, so just within the grasp of the human eye.strangely I've lived and traveled in 5 southern hemisphere countries and don't think that I ever bothered looking for sigma octantis. Any guide book to finding the south celestial pole will just say that there are no,unlike polaris and the north pole,no bright stars near the south pole and you should use a triangular alignment twixt acrux and alpha centauri, the apex of the triangle being the pole.a shame a bit like Uranus always gets missed off the list of naked eye planets.
     
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  2. Dave In Vermont

    Dave In Vermont Well-Known Member

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    Dave In Vermont, Jun 20, 2018
    #2
    Uranus (and Neptune) serve to show how different people percieve color, this as everyone's eyes are are a bit different.

    One good tool to demonstrate this is the Munsell Color-System. Simply find and note the color you see Uranus to be to you match this on the chart. This particular chart can be found here:

    http://www.andrewwerth.com/aboutmunsell/

    Enjoy!
     
  3. kevan hubbard

    kevan hubbard Well-Known Member

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    kevan hubbard, Jun 21, 2018
    #3
    I think with bigger telescopes colouration of Neptune and Uranus can be seen but the biggest telescopes I've seen them in is a 3" refractor,Japanese maker unknown (looks like ones sold as unitron)and a tasco 4 1/2" reflector(at that point in time(early 80s)tasco did fairly good stuff...they don't now!with these small scopes these planets where star like an a hint of green with Uranus. A quality 3" might just pull up a disk with Uranus on the highest powers it can bear.I doubt a 4 1/2" reflector could being less light efficient than a refractor.
     

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