Monday 5 November 2012

How to find Orion's Belt, Orion Nebula, Pleiades Star Cluster and Hyades Star Cluster

Today we will be discussing some very interesting objects which can be seen nowadays from Lahore very comfortably. Orion's Belt, Orion Nebula, Pleiades Star Cluster and Hyades Star Cluster,  all fall in or around the constellations ORION and TAURUS.
These constellations can be seen over Punjab starting at nearly 10 PM nowadays. The visibility and the height of these constellations increases with time and can be seen very clearly at around 12 PM, 1 AM. (of course if it isnt cloudy). This article is written as if these two constellations are between east and zenith. (That is why times are also mentioned). Because once past the zenith, the directions up and down and right and left will become vague.
First the plain night sky view is given, then with constellation lines. Then two edited views are given to help you find the objects.






Orion's Belt:

Asterisms are easily recognizable star patterns in the night sky. It may be a part of an official star constellation or not. Orion's Belt is an asterism in the Orion Constellation. It is one of the more easily visible asterisms and is also a very important one.
Three stars form the Orion's Belt:
  1. The Westward star - Mintaka, 915 light years away. (App Mag 2.4)
  2. The Middle star - AlNilam, 1340 light years away. (App Mag 1.65)
  3. The Eastward star - AlNitak, 736 light years away. (App Mag 1.85)
Orion's belt can be located by its characteristic shape, 3 stars in a straight line in close proximity. You can use Stellarium to locate the Belt in your area. Nowadays, in Punjab, it can be seen after 10.30 PM, but becomes clearer as time passes. As you know, it will be much more easily visible on moonless nights. To confirm that you have seen the Orion's Belt and nothing else, look at its right and left. You should find one star each on both sides almost at similar distant from the belt. The one on the left (towards North) will have a slight yellowish or orange hue. This is Betelgeuse. The one on the right (towards South) is Rigel. The diagrams above illustrate this. Also nowadays Jupiter is visible in the constellation TAURUS. So look below the (i.e towards East of the) Jupiter and slightly towards the right (towards South) to find the Belt.

Also, Orions Belt forms two triangles (depicted in red and green)
  1. One with Rigel and Saiph (the Red one)
  2. The other with Betelgeuse and Bellatrix (the Green one)

Orion Nebula (M42):

Distance = 1350 light years.
Apparent Magnitude = 4.0, so relatively good atmospheric conditions are needed to see this.
Closest region of massive star formation to earth. (Nebulas are where are stars are formed)

It is very easily seen when you have found the Orion's Belt. Just look in the middle of the Red triangle mentioned above. You will see a trail which is composed of 3 objects. It is called the Orion's Sword. The brightest object is Iota Orionis (Hatsya/Nayyar al Saif- >2000 ly away), App Mag 2.75. The middle object is the Great Orion Nebula

Hyades Star Cluster:

Distance  = 150 ly

It is a star cluster in the constellation Taurus. It forms a "V" along with Aldebaran (a red giant). Although Aldebaran itself is not a part of the cluster.
To find it you have to find Aldebaran. Just look up (or West) from the Orion Belt. It is said to be in line with the Belt. But we have found "above and between Orion Belt and Betelgeuse" a more apt description. So look up from both the Orion Belt and Betelgeuse (following the yellow lines in the diagram). You will find a star with the slightly yellowish or reddish hue, Aldebaran. Just make out the "V", and that is Hyades!!
Nowadays, Aldebaran is just besides Jupiter, so look to the right of (or South of) Jupiter.

Pleiades Star Cluster (M45), "Seven Sisters":

Distance = 400 ly

Also known as "Surayya" in Arabic. (Mentioned in a Hadith related to the advent of Messiah, "when belief will have gone to Surayya, someone from among the Non-Arabs will get it")

It is also very easy to find. After locating Aldebaran, just look up from it (or South of it). You will see a faint cluster. This is Pleiades. It looks more like a cluster when you are looking slightly off-center instead of looking at it directly (Because you are looking by the "rods" of your cornea instead of the "cones" when you dont directly look at it). When you look at it directly, you can make out the individual stars. Seven stars are easily counted (therefore the name "Seven Sisters")

These are very easily found, yet very interesting objects. Do see them with your own eyes. Please feel free to comment if you find any difficulty in finding anything.





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