Wednesday, December 13, 2017

Write-up on Gemenids Meteor Shower.

Original Post by Helen Avery
  



 The Geminids meteor shower is caused by an asteroid called 32 hundred Phaethon, and Phaethon has a legend all of his own — the most detailed of which was written by the Roman poet Ovid, in the epic Metamorphoses, in 8 AD.

 The beautiful, but tragic, story goes that Phaethon’s mother reveals to him that he is, in fact, the son of Phoebus — the God of the Sun — and disbelieving the story, Phaethon goes to Phoebus to ask him if it’s true. Phoebus tells his son that he is correct, and in order to prove his divine lineage he will grant Phaethon any wish he desires…

 Now Phoebus is the God of the Sun and to the Romans, the sun was a blazing chariot  that was pulled across the sky by horses, and guided and driven by Phoebus… So what do you think Phaethon wished for? To drive the chariot for one day.

 Despite knowing this is a terrible idea because the chariot requires incredible skill and stamina to control, Phoebus stands by his promise, and reluctantly gives his son strict instructions on how to drive the chariot, telling him never to drop the reins… 



 But as soon as Phaethon sets off, the horses, sensing a different reins-man, begin to run wild, and Phaethon is his panic lets go of the reins… What happens next according to Ovid is both beautiful and tragic. The horses zoom up into sky, around the heavens, swooshing past the Moon who can’t believe what she’s seeing, before flying down so close to Earth that meadows are consumed and scorched, cities go up in flames, and nations are reduced to ashes. The whole of Earth is on fire.


Unable to stand the heat any longer, the Earth pleads with Jupiter to intervene. And Jupiter launches a lightning bolt at the charioteer, Phaethon, killing him in an instant, and bringing an end to the destruction.  And as the body of Phaethon is hurled from the chariot, it hurtles headfirst through the air leaving a trail of sparks behind it that appear to fall down to Earth like stars — or indeed the Geminids…

Wednesday, March 15, 2017

Meteor Showers



A meteor is a bright streak of light in the sky (a "shooting star" or a "falling star") produced by the entry of a small meteoroid into the Earth's atmosphere. If you have a dark clear sky you will probably see a few per hour on an average night. During one of the annual meteor showers you may see as many as 100/hour. Very bright meteors are known as fireballs - if you see one please report it.


Meteor showers are formed usually by the dust particle or debris left by comets.




When comets come closer to the Sun, the particles evaporate forming the famous tails we love to observe. Such particles get left behind to form the meteor showers.




As illustrated in above picture, the Preseids Meteor shower origins from Comet Swift Tuttle and we see the meteor shower radiant from Constellation Preseus, Hence the name.

One might get frustrated trying to experience a meteor shower as it is not similar to raindrops falling. Usually, a very good meteor shower would produce around 120 meteors per hour. i.e. around 2 per second. However, the meteors, though originating from a precise location, could appear anywhere in the sky as the location it enters the atmosphere and the size of the particle would be the deciding factor of whether we would be able to observe it. Usually, Meteor showers are best visible during very dark time of the night and with less light pollution - a full moon is a big negative factor to observe a meteor shower.

There are many meteor showers that occur during a calendar year and some of the famous ones happen in January, August and December. Some are listed below

January - Quadrantid Meteor Shower - Usually peaks around January 2nd
April - Lyrid Meteor Shower - Usually peaks around 22nd April
August - Preseids Meteor Shower - Peaks around 12th August
October - Orionoids Meteor Shower - Leftovers from Comet Halley - peaks around 21st October
December - Geminid Meteor Shower - One of the Brighter showers - usually peaks around 13th December


There are many more meteor showers that happen during a year and all are communicated to the alert application for the benefit of Sri Lankan public.

Tuesday, January 31, 2017

The Andromeda Galaxy





The Andromeda Galaxy is the closest Galaxy to the Milky Way Galaxy that we are in. Hence, logically, it should be visible isn't it? But, how many has observed / seen it ? 

The reason is that the Galaxy is so far away, you would see it as a faint single star. The below illustration indicates the distance between the two galaxies. If we see the largest and the brightest star in Milky-way as a dot, Andromeda being at the distance it is, appear faint too.  



However, it is observable to the naked eye if you are outside the city limits. Colombo, is quite bad as an observing site. However, a decent pair of Binoculars should do the trick.

So, How do we find it ?



In the night sky above Sri Lanka, Andromeda is to the northern hemisphere. Watch for the Constellation Orion - Draw a mental straight line towards north west direction and you should arrive at the area that is circled in red in the above diagram. You would see the below star charts in this area and locate the Galaxy as shown. Mind you, it is not the colourful Galaxy you would see as in the first picture of this blog - those are long exposure (at least 30 minutes) shots that makes it colourful. 





If you observe the sky from a clear, unpolluted location, you would most probably see a sight as below - it would be easier for anyone to spot the galaxy through naked eye if the skies are really clear. What you see like a puff of dust is Andromeda. 



If you use Bino's or telescope you would see something like below.



Happy Andromeda Hunting. Please provide feedback if you spot the Galaxy and feel free to share pictures. You can comment below. 

Saturday, January 21, 2017

The International Space Station Visible Passes

Click on images for larger versions and please do share with your friends who are fellow enthusiasts.



As of now, The International Space Station (ISS) is the Largest Man Made artificial object in the Sky. 


The ISS maintains an orbit with an altitudeof between 330 and 435 km (205 and 270 miles). It completes 15.54 orbits per day and is one of the most visible space objects from Earth. Below is a long exposure photograph of the Space Station crossing the sky. 



The ISS could be so bright at times, it becomes brighter than Venus - the brightest object we see in the sky apart from the sun and the moon. The below picture indicates the moon and ISS - ISS is the bright object (Dot) to the left of the moon. 



Additionally, the spotting the ISS crossing the disk of the Sun and the moon also can be described as phenomena that one should not miss. 





The passes of the ISS over a given Geographic location could be calculated and informed to the public. 

Below is a video of the ISS passing over land.




NASA also provides a 24x7 live feed from the ISS - Enjoy the view of earth from space below.



Enjoy the sky watch !

Friday, January 20, 2017

The Southern Cross (Crux Constellation)

Click on images for larger versions. Please share with fellow Lankans who wish to learn and enjoy the beauties of the night sky.


The Southern Cross or the Constellation Crux is visible most months throughout the year and is visible in the southern sky.

The importance of this constellation or star pattern is that when you connect the stars in the form of a cross, it always points to the absolute south or the south pole of the earth.


In January, it is visible in the morning skies and will shift to the evening skies by June. However, based on earth's position vs. the Sun, the constellation is one of the most visible and beautiful sights in the skies..


Enjoy ...


Monday, January 16, 2017

The Orion Nebula

(Click on images and enlarge for better viewing) 

The Below Image shows one of the most prominent constellations in the Night Sky - The Orion Constellation. (Click)




This was also made famous through the first of the movie series "Men In Black" starring Tommy Lee And Will Smith. However, as oppose to the Galaxy on Orion's belt (Which is not there in the center of it as mentioned in the movie itself), there is Orion Nebula (a.k.a. - M42)(Click)



The constellation is visible most of the times through out a year. However, these days (January 2017) the constellation is clearly visible and close observation shows the Nebula as a powder puff.  


This is one of the most visible Nebulae to the naked human eye. 


It is better viewed through Binoculars or Telescope. But, it is clearly visible out side city areas where there is less air pollution. Below is a long exposure photograph of the nebula - Yes, if you wonder why you don't see the multitudes of colour to the naked eye, it doesn't happen that way - you will always see stars more or less in white. It is only a planet or an object like comets that would have a slight variation in colour. The pretty pics we see are due to very long exposure of camera (more than 15 minutes)


Beautiful Isn't it ??

Saturday, January 14, 2017

NGC 2451 Open Cluster - January



An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age.


The NGC 2451 Open Cluster probably discovered by Giovanni Battista Hodierna before 1654 andJohn Herschel in 1835. In 1994, it was postulated that this was actually two open clusters that lie along the same line of sight. To the Naked Eye, a cluster usually is seen as one star due to the distance from earth. However, mindful observation allows you to see many stars combined together as in a powder puff. 



The open star cluster NGC 2451 in Puppis (click) will be well placed for observation during January and beyond. It will reach its highest point in the sky at around midnight Sri Lanka time.  Refer below Map and the red circled area. Click on image to enlarge.   
At a declination of -37°58', it is easiest to see from the southern hemisphere but cannot be seen from latitudes much north of 32°N.
From Sri Lanka, it will be visible between 19:54 and 04:30. It will become accessible at around 19:54, when it rises 15° above the south-eastern horizon, and then reach its highest point in the sky at 00:14, 45° above the southern horizon. It will become inaccessible at around 04:30 when it sinks to 15° above your south-western horizon.
At magnitude 2.8, NGC2451 is visible to the naked eye, but best viewed through a pair of binoculars.

Friday, January 13, 2017

Let's have some fun !



This blog will be for those who live in Sri Lanka and is interested in Astronomy. The blog will include the observable phenomena that happens up above, little bit of weather and some fun activities we can engage in.

Additionally, if you are interested to get instant messages to your phone on the wonders that happens in the Sky Above You, you could also SMS "REG sky" to 77000...

As per regulatory requirements, there will be a charge of Rs. 2 per SMS received. However, there will be no subscription / recurrent charges and SMS's are sent only during an observable phenomena.