63 replies to this topic

[Pinguin]

I'll just mark this on my calendar...

[Chrlzs]

As Waspie said, guessing about comets is just prone to complete failure - small differences in trajectory and the amount of outgassing (which depends mainly on the composition of the object) can make the difference between being bright, or being effectively invisible..  So, just wait and hope..  One small correction - don't look 'up', as it will more likely be seen near the horizon shortly after sunset or before dawn.

BTW, when the last good'un showed up down under (Comet McNaught), I took a whole pile of images, but my favorite one was when a group of amateurs plonked themselves right in front of my viewing position and used phones, cameras and torches to destroy their/my night vision while trying to setup a cheap reflecting telescope (which is not a great way to view a comet..).  But the result made for an interesting image, so who's complaining..!




To Abramelin..

Abramelin, on 28 December 2012 - 05:39 PM, said:

...
...{Link to hoax site - 'Weekly World News' removed}...
...
First: this is the only source with this news;

That didn't ring alarm bells?  How about the other headlines, Like 'Kardashian's Butt Explodes'?

It's a fake news site.  There is no Asteroid 2014AZ5 - there can't be, as they are named after the year of discovery.  It's not 2014 yet...

Please, Abramelin, take that site off your Favorites...

[Abramelin]

Chrlzs, on 01 January 2013 - 10:40 AM, said:

To Abramelin..

That didn't ring alarm bells?  How about the other headlines, Like 'Kardashian's Butt Explodes'?

It's a fake news site.  There is no Asteroid 2014AZ5 - there can't be, as they are named after the year of discovery.  It's not 2014 yet...

Please, Abramelin, take that site off your Favorites...

Of course it rang alarm bells,lol.

But I found out a zillion sites had already copied it, so I thought it would be a good idea to bring it up here, and then add my doubts about it.

[ealdwita]

The best view I ever had of a comet was in Singapore in 1966. It was many years afterwards I discovered it to be Ikeya–Seki, apparently the brightest comet seen for a thousand years!

[jylppy]

Here is image taken 2.1.2012 and simulation video.

http://c2012s1.info

[libstaK]

jesspy, on 31 December 2012 - 09:00 AM, said:

Lol maybe the Mayan calendar is based on this comet. Do we know how long its cycle is yet? If its 26000 years that would explain the calendar maybe lol. A feathered serpent could be referring to a comet. Either way it would be great to see. Do we know yet if people in the southern hemisphere will be able to see it?

If it is going to be around for approx a month in the direction of the setting sun, the whole world will get a chance to see it - I hope.

As to the doomsayers, yep they'll be jumping all over this, I can see it now. "The Mayan calendar was too eroded for us to notice before but there is a year zero before the year 1 of the 26,000 year cycle, so the calculations are off by a year".

[Chrlzs]

jylppy, on 04 January 2013 - 12:03 PM, said:

Here is image taken 2.1.2012 and simulation video.

http://c2012s1.info

You might get a few more hits if..
- you identified yourself a bit more (both here and on that site)
- you clarified exactly what your intent was with the site

It looks interesting, but no 'About' page?  People tend to be wary of clicking blind links, especially to .info sites..
Also, while the simulation image is 'exciting' (perhaps *overly* so), what is it based upon?  How are you simulating the brightness and length aspects?

[Archimedes]

Medium Brown, on 29 December 2012 - 08:18 AM, said:

Well having read it more carefully I think we've got a 50/50 chance.

A 50/50 chance of what?

Quote

I think it being brighter than the moon is a pretty fair assessment of a comet in full flight.

What is a comet "in full flight" and how is the brightness a "pretty fair assessment" of that?

Quote

It's not surprising people are getting hyped up after what Shoemaker-Levy did to Jupiter.

But this comet is not predicted to be on a trajectory that impacts or comes close to earth, so what harm can it cause.

Also, what did Shoemaker-Levy "do to Jupiter"?  A comet hitting a gas giant is like a fly hitting a train.  It might make a very small temporary mess on the window, but the train keeps on going as if nothing happened (which it practically didn't).

Quote

My idea of amateur astronomer hell would be it if it suddenly became overcast.

Why would "suddenly" becoming overcast make a difference to a comet that is predicted to be visible for months?

Edited by Archimedes, 07 January 2013 - 01:49 AM.

[Frank Merton]

A few things.

As this comet passes nearest the sun, it will actually enter the sun's atmosphere.  There is then a good chance that tidal forces will break it up, ruining the show scheduled for us to get later.

When the comet is close to the sun, you should be able to see it in daylight just by holding your hand in front of the sun.  (Be careful not to look right at the sun for more than a second or two -- get your hand in place before you start looking closely).

Assuming the comet survives the close passage, we will have an excellent view for over a month, day and night, although of course best at night.  It will move slowly through star fields and participate in the diurnal rotation of the sky.

As it will come only a little less than an AU (the average distance from the earth to the sun) from us, there is no possibility of it having any effect on the earth.  It is an especially large comet, so we are lucky in that respect.  An actual collision with such an object would sterilize the planet.

As ways to end our world, comet collisions are pretty far down the list.  They come in at all angles (unlike asteroids that tend to be in the plane of the earth's orbit) and generally don't even penetrate to the earth's orbit.  When they do, consider the earth as a target 8,000 miles in diameter in an orbit that is 93 million miles in diameter.  When you convert that to the surface of the sphere (given by 4 pi R^2) one sees that the chances of a comet coming in at just the right direction is extremely small.  Asteroids therefore present a much larger threat, and they are much more common.

However, there is one bad thing about the comet scenario.  It could come in from behind the sun, so that we would not see it until it was right on top of us.  Most of the time we would have a year or more's warning.  If we do our job of cataloging near-earth asteroids, any that present a danger should give us a century or more's warning.

[Chrlzs]

Just one thing...

Frank Merton, on 23 January 2013 - 10:23 AM, said:

It could come in from behind the sun, so that we would not see it until it was right on top of us.

Umm, I don't wish to denigrate the fact that we could be caught unawares under some circumstances, but... orbital mechanics would suggest that there is only a tiny, tiny chance of something travelling exactly opposite to us in order to be 'behind' the Sun at the entire time it is brightening sufficiently to be seen..

And are you aware of the STEREO spacecraft, and where they are?

[Frank Merton]

Yea I'm aware; one can only cover so many details in a short presentation.

[CrimsonKing]

Hope this lives up to the hype,i have a place i go to far away from any distractions on top of a hill when i want to sky watch no lights for miles.Can even look down over the trees and see the moon bouncing off of the water its perfect!

[Chrlzs]

CrimsonKing, on 23 January 2013 - 11:26 PM, said:

Hope this lives up to the hype,i have a place i go to far away from any distractions on top of a hill when i want to sky watch no lights for miles.Can even look down over the trees and see the moon bouncing off of the water its perfect!

I trust you are good photographer and have a half decent camera?  If not - there's some time to learn and save up!

[Frank Merton]

My memory is hazy but I recall quite a few years ago renting a van and going out to the countryside to see if we could see Hally's Comet (we were told to get away from city lights for best viewing).  The van was full of kids and young adults and a few more mature types.

We attracted the attention of the local authorities, who wanted to know what we were doing (although I'm sure we looked harmless enough).  When we told the man, he grinned and pointed it out for us.

I was a little underwhelmed.  It may be that we were not in a good area for seeing it, and the sky in this part of the world is always a little hazy, and I was busy keeping track of the kids and counting noses.  Still, now that we knew what it was, it was not hard to find even in the city.

I think now that I know a good deal more about comets, I will appreciate it more.  It is a huge fallacy that ignorance of a phenomenon's science leads one to be more appreciative.  I think when one really knows what the thing out there is about, one appreciates it more.

[Waspie_Dwarf]

Frank Merton, on 24 January 2013 - 12:43 PM, said:

I was a little underwhelmed.  It may be that we were not in a good area for seeing it, and the sky in this part of the world is always a little hazy, and I was busy keeping track of the kids and counting noses.  Still, now that we knew what it was, it was not hard to find even in the city.

The 1986 apparition of Halley was not a particularly good one. The apparition of 2061 will be worse still. Mind you, if I'm still alive when in 95, I'm hoping to observe that one from space.

Frank Merton, on 24 January 2013 - 12:43 PM, said:

It is a huge fallacy that ignorance of a phenomenon's science leads one to be more appreciative.

I couldn't agree more. An understanding of biology makes a butterfly no less beautiful.