A little something about comets.

So here we have a couple of guys in our group who’re into comet hunting and such. We’re only inclined to think that these are just bound to be futile attempts by passionate amateurs ..in whom schizophrenia takes over and their efforts end up in the drain; Afterall – it’s an endeavour for any astro enthusiast to be lucky enough to make his name immortal .. Have a comet named after him – a shortcut for eternal fame.

Not a lot of us – the present generation have got to see a lot of comets , for we would’ve known the thrill of witnessing a celestial nomad otherwise. There’re a few among us to whom Hale-Bopp remains the sole divine thing ever – Something which propelled them into astronomy and remains etched in their memory forever.

As we all know – comets are these cosmic nomads that come and go; LINEAR and NEAT which were formed solely for the detection of these cosmic visitors – discover them in the order of hundreds every year and ofcourse the fainter among these go undiscovered every year. There must be innumerable of these comets , with orbits so eccentric that they pass only a few solar radii away from the sun during their perihelia and stretch out to the vast realms of the hypothetical oort cloud surrounding the solar system. Few discovered by amateurs as well – and this gives us the privelege of having then named with ours.

So what was it about Hale Bopp that was so inspirational and enthralling to a lot of people .. this if you have about 200,000 such rocks floating around in space ?.. The answer is that Hale Bopp was something different .. It wasnt the horrifyingly faint and diffuse comet that would’ve been anything but disinteresting; For it belonged to the genre of comets that were the great ones of their years.

At it’s brightest – comet Hale Bopp – The great comet of 1997 and the last great comet as yet – outshone Sirius in the nightsky rather easily ; Had a clearly visible coma and a tail that stretched out tens of degrees long. A comet that induced more interest in the general public than our more famous celestial vistor- Halley and remained visible to the naked eye throught a record 18 month period.

So here are these comets – classified as Great Comets; These are the ones that not only hit magnitude of naked eye visibilty but go on to be a bigger sensation. A rather different definition broadly defines these to be comets that hit magnitude 0 or higher. And over the centuries and millenia , we’ve had many accounts in history of comets that’ve dazzled the skies and amazed the people over.

Here’re just a few lines written about some sensational comets of the last couple of centuries.

The Great Comet of 1811 : This comet held the distinction of being the comet visible longest to the naked eye – a full 260 days , all until Hale Bopp trounced it with a whopping 18 months of naked eye visibility. But was one of the greatest comets ever – without a doubt .. A tail that stretched across a full 60 degress of the night sky ! Must’ve been some sight .. It has a period of 3757 years and the next perihelion date is a while away..

The Great Comet of 1843 : A comet that shot right out of the blue . The comet had the longest ever tail recorded in history – stretching upto 2 AUs long.. Until Comet Hyakutake’s was found to be 4AUs long – in 1996. This comet was only a fraction of solar radius away from the sun at perihelion and was observed in broad daylight just a degree to the west of sun ! Next perihelion date is 2358AD.

The Great Comet of 1858 : The first ever comet to be photographed and one of the most brilliant ones of the 19th century; Next perihelion set at 3811 AD.

The Great Comet of 1861 : Another great comet of a century that saw a lot of them .. At perigee , the comet was a mere 0.13 AU away and the earth was actually within the comet’s tail !

The Great Comet of 1882 : Another daylight- Comet ! As astronomers record .. was clearly visible in daylight and right next to the sun. Magnitude was estimated to be -17 !.. The only comet ever known to have been seen on transit across the sun’s disk. The comet fragmented into atleast 6 parts later but remained visible prominently. The comet’s next perihelion is likely to be in a few hundred years.

The Great Comet of 1910 : None other than the Halleys comet ! And at it’s spectacular ever best.. Transit across the solar disk and was visible in daylight !…And it’s tail warped the earth for a few days as well.

The Great Daylight Comet of 1910 : How lucky can people get.. 2 great comets and in the same year.. Stayed brighter than venus for a long long time ; Brightned so quickly that it’s discovery is attributed to no individual.. Was noticed by a lot of people independantly. next perihelion is more than a while away – 4144877AD.

The Great Comet of 1927 : Named Skjellerup-Maristany after it’s discoverers. A comet that brightned to naked eye visibilty even from the city lights. Was known for it’s yellow appearance caused by sodium atom emission. Next perihelion set at 38000AD.

The Great Comet of 1957 : Named Arend-Roland. Hit naked-eye visibilty as the rest did , but different from them all considered the fact that it showed a prominent anti-tail – which pointed toward the sun rather than away. Is calculated to have a hyperbolic orbit which implies that this is something thats set never to return..

The Great Comet of 1965 : Named Ikeya-Seki. Another of the sungrazers’ genre. Was as bright as magnitude -17 and was visible in daylight (obviously ! ) The fragments of the same are set to return in 800 and 1056 years respectively.

The Great Comet of 1976 : Named West. The comet split into 4 fragments at perihelion. A long period comet – Next perhelion scheduled a good 254,000 years away.

The Great Comet of 1996 : Named Hyakutake. Was disovered by a japanese amateur when at 11th magnitude and only a few days after he had discovered his first. The comet has the longest ever tail recorded in history so far – a full 4 AU’s. The comet was the first one known to be emitting X-rays. The comet’s tail was about 80 degrees long at one point of time ! Was a long period comet – at 15,000 years but gravitational influences of Jupiter and co have only lengthened it to 72,000 years.

And finally..the last one of them all..yet.

The Great Comet of 1997 : Hale Bopp ! – was always bound to be something special…far far away and at 11th magnitude when discovered ( In the vicinity of M70 in Saggitarius ).. But was 50,000 times brighter than Halley when it was at the same place. A nucleus that was 50KM big …and bound to cause a sensation. Trounced the 1811 comet’s record of longest naked eye visibilty – staying visible for a full 18months. Large telescopes continue to track the comet even through the outer solar system and are expected to continue doing it until 2030 when the comet will be fainter than magnitude 30. A lot has been said about it already.. for further details – consult your dad who might’ve seen it !.. Next perihelion scheduled – 4400 AD.

So much for the last 10 years – barren without the appearance of a great comet .. Just sad that my interest for astronomy has been but a recent affair of 5 years.. If only I could’ve been there when Hale-Bopp was around..

Anyway.. 10 years past the last Great comet, all the more reason to believe that there should be one heading our way after this lean patch. Knowing how unpredictable and queer comets can be ..there’s no guarentee that we cant sight one next week !

Now, It probably makes sense for us people to hunt for comets.. All we could do with is a good instrument, clear skies and lots of luck.

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