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Polaris


trogre
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Orion is the easiest constellation to spot from my garden. Naturally it is a different position as the night progresses.

I have been having problems trying to spot Polaris and think I have sussed out it is due to my inexperience. I read that Polaris is at the end of Ursa Minor`s tail but some of stars hard to spot with naked eye. Easier is to draw a line from Merak –Dubhe of Ursa Major to Polaris which is in the North.

I had printed out a map of Ursa Minor & Major showing line pointing at Polaris.

I was confused as when I looked at Ursa Major or what I thought was Ursa Major at around 20.00-ish it was not where it should be, more NE. This meant if I drew a line to Polaris it would be in the East!!

Went onto Stellarium and got up Ursa Minor & Major and used the time setting to go from 9am to 9pm. That is when it dawned on me that Ursa Minor & Major do got go across the sky but pivot around Polaris!! I think from what I can see the map I have with Major on the bottom was taken around 9am.When I look at 20.00 it is turned 180° so basically upside down. What I thought was the 2 bottom stars of Major, Dubhe & Megrez were in fact the 2 bottom stars of Minor Pherkad & 21 Umi .Basically I was l looking in wrong direction using wrong constellation.

A good lesson learnt here but that raises another question. Ursa Minor & Major as I changed timeline in stellarium rotates around Polaris. On the other hand if I do the same to Orion it moves across the sky depending what time it is but always stays the correct way up.

Not very good at explaining myself so if I have confused anyone I will try to explain in a better way. Thank you

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Polaris is very close to the North celestial pole. All the stars appear to rotate around this point. Ursa Major and minor are circumpolar constellations. They never set ( go below the horizon ) from the latitude of the UK. Orion is not circumpolar. Like the moon and the planets it rises and sets and is not visible from the UK in the summer. The easiest way I found to understand this was to use a planisphere which shows through a window what is visible at the different seasons of the year.

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I suspect the 2 stars named are "The Pointers", so named as they point to Polaris. :grin:

Actually that is sort of the way to find Polaris, Ursa Minor is a faint constellation and locating it is not easy.

Would say Ursa Minor is almost impossible from Swindon, it used to be OK from Wroughton many years ago. :eek:

Every thing appears to rotate around Polaris, or the equivalent at the South end of the planet.

The ones that remain above the horizon are the circumpolar constellations, about 7 if I recall - Ursa Minor, Ursa major, Casseiopia, Cephus, Auriga, Draco (very faint), Perseus. There may be others but it depends on which set you use.

By the way if you use the pointers to go to Polaris you can go the other direction and they "point" to Leo - which may or may not be visible.

You can follow the "arc" of the handle to curve round and locate Arcturus (red star), refered to as "Arc round to Arcturus" :grin: .

Orions Belt points (sort of Left to Right) to The red star Aldebaran and the Hyades cluster, then on a bit more to the Pleiades cluster.

If you use the belt and go the other way (Right to Left) then they point to Sirius.

So there are a few more to play with.

Several "pointers" in Casseiopia, just more difficult to explain.

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Get a compass. Get a protractor and level it as best as you can. Find out your latitude and, using the protractor, practice raising your arm up to emulate (fill in with your latitude number) degrees.

Once it gets dark, go out with the compass and (a red torch/flashlight would be helpful here) find magnetic north. Aim your arm straight up the line to north the compass points to. Now raise your arm to your latitude. You will see a star that's brighter than the rest there. At 1.99 magnitude, Polaris is hard to mistake in the area you should be looking. And it will be where you saw it tomorrow night - and 6 months from now as well.

Clear Skies,

Dave

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