September
night sky for mid northern latitudes

(Note: The names of the constellations are given in bold and the names in italics are the names of heavenly bodies in Indian astronomy. For better understanding have print out of the map.)
The Sky Map :and: Solar System Object

It is still time for the observing season but we do get clear skies now and then. September also brings in occasional good sunshine. It is time to get ready for the observing run.

On a weekend or on a holiday if you have a good sunshine you might as well take out your binoculars and telescopes and give them a bit of a sunshine so that if some moisture is trapped then it would evaporate. Long spell of rains have washed out the dust in the atmosphere and if the sky clears up one has a crystal clear sky.

You can start with southeast where Scorpius, the Scorpion  [Vruschik] is still well above the horizon. This is one of the constellations that quite resembles its name. The brightest star in this constellation is Antares (Jyestha). 

Sagittarius [Dhanur] is following  Scorpius. Center of milky way lies in this constellation. This region between Scorpius and Sagittarius  contains number of clusters and nebulae and it is worth sweeping this with a good pair of binoculars. Look for M6 and M7, the best one is M22 a globular cluster. This cluster resembles a comet that is just discovered. It appears a fuzzy patch of light through a pair of binoculars.

Turn to west Arcturus, (Swati) is still above the horizon. Turn further right to northwest. Only the tail of Ursa Major, Great Bear is now above the horizon. Look for the second last star in the tail Mizar. This star is visual binary. It has a companion Alcor. Both the stars can be be seen if you have good eyesight. In Indian astronomy Mizar is Vashishtha and Alcor is Arundhati.

Well above the western horizon, above Bootes, you can trace out Hercules [Shauri]. The object to be looked for is M13 a globular cluster. This is a compact cluster of stars.

To its north is Draco, the Sea Dragon (Kaliya). It winds quite a bit through different right ascensions.

Right overhead is (almost) a right angled triangle of three bright stars. The stars belong to three different constellations. Altair [Shravan] in Aquila, the Eagle [Garuda] and Deneb in Cygnus, the Swan [Hans] are almost aligned on the north south line. To there is Vega [Abhijit], in Lyra, the Lyre [Swaramandal].

This group of stars was named summer triangle by Patrick Moor. All the stars are the brightest stars in their respective constellations. Vega which is the brightest star in the northern hemisphere. The second brightest of the summer triangle is Altair. Shravan is 22nd Nakshatra.

Look for Albeireo and M39 in Cygnus. Alberieo is a beautiful binary star whose one component is red and the other is blue. 5 inch mirror will split them.  M39 open cluster or galactic cluster. Easy object for binoculars.

Well above the eastern horizon is one of the 'land marks' of the night sky is Great Square of Pegasus, the Winged Horse [Maha-ashwa]. You just cannot miss it. The sides of the square are almost aligned north-south and east-west. The stars on the western arm of the square make our 25th nakshatra Purva Bhadrapada and those on the eastern arm are of 26th nakshatra Uttra Bhadrapada. Purva and Uttara are in the sense of earlier and later respectively, in their movement in the sky and not in the sense of direction.

Halfway between Pegasus and the horizon is Cassiopeia [Sharmishata]. This is a constellation in 'M' shape with its right leg pulled too much to right. You might recall that Saptarishis are used for finding north direction in the night. This constellation can be used for finding north when Saptarishis are below the horizon. Take the first three stars of 'M' which make an equilateral triangle. Now take perpendicular bisector of the first and star. This line, when extended towards horizon will go through the Polaris [Dhruva], Pole Star. Using a pair of binoculars if you scan on the line joining third and fourth stars of Cassiopeia and extending to east you will reach a binary open cluster of stars h & c. These are lovely pair of star clusters.

 


The material here can be used freely.
It is, however, expected that the source may be acknowledged.
 Credit : Inter-University Centre for Astronomy and Astrophysics, Pune.)

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by
Arvind Paranjpye - arp@iucaa.ernet.in  +91 20 2560 4601
   Samir Dhurde - samir@iucaa.ernet.in +91 20 2560 4603

Page created June, 2007 and Updated  Sep, 2007