Pole Stars

Currently, Polaris (Alpha α UMi) shines at magnitude 2.0 and lies just 0.7° from the North Celestial Pole (NCP).  Precession of the Earth’s rotation axis will bring the NCP to within 0.5° of Polaris in March 2100, its minimum distance.

The situation for the South Celestial Pole (SCP) is not such a happy circumstance.  The nearest naked-eye star to the SCP at present is neither near nor bright.  Sigma Octantis at magnitude 5.5 is not easy to see with the unaided eye, and being 1.1 degrees away from the SCP doesn’t win it any awards.  Besides, precession is moving the SCP farther away from Sigma Oct, not nearer.

One wonders, will precession someday bring us a south celestial pole star worthy of the name?  Even, perhaps, comparable to Polaris?  Here’s what our stargazing descendants can look forward to:

Cha = Chamaeleon; Car = Carina; Vel = Vela

So, around 8100 A.D. Iota Carinae and around 9220 A.D. Delta Velorum will serve admirably as southern pole stars every bit as good as Polaris does now in the northern hemisphere.

Now, for the northern hemisphere…

Cep = Cepheus

Up until the year 10,000 A.D., no northern pole star will be as good as Polaris is now, though 4.8-magnitude 9 Cephei will be very close to the north celestial pole around 7400 A.D.

Thought you might enjoy seeing what deep sky objects will come close to the celestial poles, so those are listed in the above tables as well.

2 thoughts on “Pole Stars”

  1. It seems that there is a publication conspiracy to avoid providing amateur astronomers with information to simply and accurately polar align telescopes the easy way! All one needs is a recent reasonably high resolution photograph of the North Celestial Pole area of sky with the North Celestial pole accurately marked on it, showing stars down to magnitude ~12. Then it’s a straight forward matter to adjust the equatorial mount’s wedge angle and support’s ground orientation so as to duplicate the given photo in the telescope’s eyepiece such that the duplicated image is centered on the NCP.
    That simple annotated picture seems to be avoided, like the plague, by every single website on the internet.
    The photos that do identify the NCP only show stars down to magnitude 5 and are useless for the purpose needed. The high resolution polar photos that are available do not identify the NCP location. Those that do contain the NCP in high resolution all appear to contain unguided star trails. There are simulated pictures with all of the required information except they are not for the current epoch. Everything published seems to be deliberately and obtusely avoiding the only useful practical information that is needed to align one’s telescope correctly or am I missing something?
    Just before I posted this, I thought I’d have an even more exhaustive check of the internet. Found a new obtuse accidentally on purpose missing of the point.- Published image with stars too faint to see on a screen.
    Kind regards, R.G.

    1. Hi Roger, I think you might be able to produce the kind of charts you are looking for with Guide 9.1 software.

      https://www.projectpluto.com/guide9b.htm

      Guide is “old school” but very reasonably priced and quite accurate. It is the software I use at the telescope to identify target stars for asteroid occultations. Here are a couple of screen shots of the current north celestial pole (NCP) location. The first is a 2˚ field and the second is a 1˚ field, both centered on the NCP.

      Guide 9.1 NCP 2˚ Field 27 Apr 2020

      Guide 9.1 NCP 1˚ Field 27 Apr 2020

      You can customize the sizes of the stars and many other aspects to suit your needs. Guide has black stars on white background print capability built in.

      One of the challenges with software plotting the NCP and stars near it correctly is that the right ascension is undefined at the NCP (declination = +90˚). Also, the right ascension of a star very near the pole can change rapidly with time. These are artifacts of the equatorial coordinate system, of course, and have nothing to do with the fact that there is an exact location of the NCP on a given date, but a lot of planetarium software programs don’t handle the poles at high resolution very well.

      Hope this helps!

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