Comets

[ashenlight]

I'm sure a lot of you will remember comet Hale Bopp from 1997, I certainly do. It was the year I turned 10 and I had received a small refractor for Christmas just gone. The views of the Moon, even in that small department store telescope were amazing, so Mum woke me up to view this comet and I was mesmerised. I couldn't quite take it in, and I wish I'd had a deeper understanding of all things astronomical, as I do now, to try and appreciate it more (yes, I know, I was only 10...)

My question is, does anyone know when we will get the chance to observe another comet like this? Will it be in our lifetime, or not for a few hundred years?

Amanda

[Psychobilly]

Lulin was a nice supise a few months ago as was Holmes with its sudden outburst last year.,..

So theres always the possibility of something spectacular turning up unexpectedly...

Peter...

[ashenlight]

I got a fairly decent look at Lulin earlier this year, didn't even know Holmes had an outburst last year! I'm just greedy and want the full blown brighter than Sirius visible for a longtime 'ooh ahh' comet. Humph.

[arad85]

My question is, does anyone know when we will get the chance to observe another comet like this? Will it be in our lifetime, or not for a few hundred years?

Amanda

Looks like every 10-25 years or so. Take a look at the page here: SPACE.com -- Predicting the Next Bright Comet

at the bottom it lists all the bright comets of the 20th Century. Would love to have seen the 1965 mag -15 one!!

[ashenlight]

arad85, thanks for that cor yea imagine a mag -15! visible in daylight too, what a sight.

[Talitha]

That's the fun thing about comets, they surprise you once in a while. Remember the stunning fantail on McNaught? We missed it here, but the southern hemisphere got a heck of a show.

Back in 2006, Comet 73P/Schwassmann-Wachmann broke into pieces and we watched them as individual events. Here's fragment C slipping past M57... i bet you'd have found the Ring easily enough Amanda, just follow the fragment's tail.

[crovax]

I was only 9 when Hale-Bopp was in the sky so all I remember is a very shiny thing in the sky that is much brighter than any star. And I am really looking forward to the next Great Comet because now I know something about them and will be able to have a closer look with my 'scope. By the way do I need to use any filters when looking at things like -15mag comet? May be moon filter or anything like that?

Also in that article I found that the comet is named after first 3 people that have reported it. Where should I report comets to and what info do I need to supply? I want to discover a comet!

[Vega]

Great thread Amanda. I remember Hale Bopp, what a sight, I remember seeing if from the centre of my town in amazement. I wish I had a scope and had the understanding that I have now. The only comet wow for me so far has been Comet Holmes as I got to see it telescopically 48 hours after the initial outburst. I can only describe it as a truly haunting sight. Very strange, distinct white sphere hanging in the sky.

Even though its been the brightest one in decades, Comet Lulin didn't really do it for me. Mainly because of its position low in the twilight for most of its Norhtern Hemisphere journey. I eagerly await the next 'biggie' too :-). Not sure I'll live to see Halley.

Matt

[brianb]

Even though its been the brightest one in decades, Comet Lulin didn't really do it for me.

Forgotten Machholz (2004) already? And McNaught (2006) was a truly great comet, if you happen to live in the southern hemisphere.

But it's not all that long since we had the brief appearance of Hyakutake - spectacular with its 50 degree tail - followed not long afterwards by Hale-Bopp, which was circumpolar and bright for months, if not all that large.

Not sure I'll live to see Halley.

I'm sure I won't. But on the 1986 performance I won't be missing much, and the next apparition is equally unfavourable.

Comets are like cats, they have tails (well, some of them do) and they do what they want. The sheer unpredicatbility is part of the charm.

[tinvek]

Comets are like cats, they have tails (well, some of them do) and they do what they want. The sheer unpredicatbility is part of the charm.

and the results are spectacular if you drop one into some water

i've got a cat that likes to sit with the tip of his tail in the fish pond, even lets the fish nibble at his fur, when he fell in though all you could see was a blur of legs and water / plants flying anywhere though once he got out he did that " i'm cool, i intended that " thing that cats do when they fall etc.

in the beginning god created the universe, the earth and all the animals, on the mornining of the seventh day he looked around and noticed he had a ball of fur left over. he pulled and pushed at it but it just wouldn't stay in the shape he wanted, in disgust he gave up and threw it down on the face of the earth. the lump of fur looked up and said "meeow" before curling up and going back to sleep

[JamesK]

Hale- Bopp was my earliest astronomical memory - I was three at the time and suprisingly remember it well. My dad got me out of bed to show me after he found me looking at a Patrick Moore book a few weeks earlier... well, looking at the pictures.... well, maybe drooling on the pictures.

Either way... it was "A Sign"!

Here's to an unexpected mag -15 (as if) to cap off IYA2009!

James.

[brianb]

By the way do I need to use any filters when looking at things like -15mag comet?

It will only be that bright when right next to the Sun, and you'll struggle to see it at all in the glare. McNaught got to about -7 in 2006 January, it blotted out the SOHO wide field images with its glare but was essentially unobservable from the ground at that point.

Where should I report comets to and what info do I need to supply? I want to discover a comet!

So You Think You've Discovered A Comet...

[crovax]

Cool, thanks! I am looking forward to having my own comet

By the way what does the following line mean:

The equinox should also be stated (2000.0 or 1950.0 being the most-widely used).

How do I determine my equinox?

Well, I guess I'll start with making my stupid RA circle work. I have terrible problems with this thing. When I tighten the screw it rotates with the coordinate pointer (the coordinate doesn't change)

Also a theoretical question about RA:

In my manual it is said that I need to point to (e.g.) Vega and set its RA. Then I can navigate on te sky. But isn't sky rotating in RA axis itself? So if I point to Vega and set RA then go rest for a while, won't Vega run away? Am I misunderstanding something? If not, does an EQ2 motor fix this issue (rotating RA without changing coordinate)?

And where should I look for them? I guess looking at objects visible with naked eye doesn't makes sense at all and comets are discovered by looking at random areas of sky. Am I right?

[brianb]

How do I determine my equinox?

It's a mistake, should read "epoch" (of coordinates - they vary slowly due to precession)

In my manual it is said that I need to point to (e.g.) Vega and set its RA. Then I can navigate on te sky. But isn't sky rotating in RA axis itself? So if I point to Vega and set RA then go rest for a while, won't Vega run away? Am I misunderstanding something?

Yeah, what the RA circle is actually measuring is hour angle, this is the difference between the object's RA and the sidereal time. You set the sidereal time on one pointer & rotate the axis till the object's RA appears on the other, this does the calculation for you.

And where should I look for them? I guess looking at objects visible with naked eye doesn't makes sense at all and comets are discovered by looking at random areas of sky. Am I right?

Yeah, unfortunately the automatic surveys get most things brighter than about mag. 20 these days - you can improve your chances by working in the areas they avoid, because of interference from the Sun; which also makes sense because comets tend to be brightest when closest to the Sun. Areas around Virgo are probably best avoided because of the huge number of faint galaxies which will cause no end of false alarms.

[Casus belli]

I was lucky enough to see Mcnaught. During a rare clear evening it was spectacularly bright with a huge tail. It was very low and set before night fell.

[ashenlight]

Great responses everyone, thank you lovely to hear all your memories of comets, and great to get some tips and tricks in too.

SGL I salute you!

[G4AQB]

I remember the joy of finding Comet Swan a few years ago and then actually capturing a blured image with my webcam.

Comet Holmes was an amazing sight with Skywatcher ST80, I could even see it without a scope from my back garden.

This is an image I took with the ST80 and Canon 350d.

[Beulah]

I was studying at University when Hale Bopp visited us; this may be a false memory, but could it be seen in daylight too? I'm sure I could. What a memorable sight, I coudn't take my eyes off it.

[brianb]

this may be a false memory, but could it be seen in daylight too?

I don't think so; it never got above mag. 0 - but it was visible in bright twilight & remained well placed for months.

[661-pete]

Hale Bopp wasn't quite bright enough to be visible in full daylight: it reached about mag. -1.5 a bit brighter than Saturn. But it was certainly billed as the 'comet of the century' though I reckon that's a bit of an overstatement if you take the whole period 1900-1999 into account.

I've lived through half of the aforesaid century, and I've seen several - and missed many! My father assured me he dragged me out of bed as a small kid, to look at Arend-Roland (1957 - the comet featured on the very first S@N programme), but I don't remember it. I remember Bennett in 1970, quite a nice bright one, and IRAS-Araki-Alcock some time in the 1980s, and of course Hale-Bopp and Hyakutake in 1996/7, but I missed Ikeya-Seki in the 1960s, West in 1976, and McNaught only last year. The sun-grazers are difficult especially if you don't have perfect weather!

And Halley in 1986 was disappointing - really faint and LP was already spoiling the view in those days.

I've just dug up the animation I did of Comet 73P (largest fragment) through the 10" newt, back in 2006 - the same one sketched by Talitha above I believe.

I think this was 1-minute frames and the animation spans about 14 minutes of real time.

[barkis]

We know comets are either short period, or long period objects.

The orbits can take them out to the far reaches of the Solar System, or just beyond the orbits of the outer planets.

When they return to the sun, they invariably come in on the plane of the ecliptic, that path in space around the sun which the planets follow.

The other breed are the great unknowns which can appear from any direction. I believe Hyakutake was about 90 degrees to the ecliptic plane. These comets are believed to have their origins in the Oort Cloud, that vast shell of material that reputedly encompasses the Solar System some 100,000 AU distant.

Perturbations must be a constant occurrence in that overcrowded junkyard where this vast reservoir of rocky bodies vie for room, and the jockeying can result in a game of snooker, where a cannon may cause large lump to start the long fall to the sun.

So who knows, another Hale Bopp or Hyakutake may well be heading our way. Beautifully spectacular. Let's hope they keep their distance from us, and we can view them from afar.

Ron.

[661-pete]

I think you've got too many noughts there Ron - 1000000 AU would place the Oort cloud 5 parsecs away - further out than Procyon! I know it's a long way out from the Sun but not that far out! But it's true that the gravitational bonding holding it all together is extremely weak, and the least nudge from a passing object (Procyon, if you like) would perturb a comet out of its orbit and start it tumbling towards the Sun. Which it would then take hundreds of thousands of years to reach.

I think most people should expect to see about three or four really spectacular comets in their lifetime, on average. The brightest in the 20th century was reputed to be the Daylight comet in 1910, but maybe Ikeya-Seki briefly outshone it.

[Talitha]

Super animation, Pete!

Yes, i think it has to be the same fragment. C was the largest and was believed to have been a main piece from the parent... probably why it had such a bright little nucleus, unlike B which looked like an elliptical galaxy. Well, at least it did by the time i saw it.

[barkis]

I think you've got too many noughts there Ron - 1000000 AU would place the Oort cloud 5 parsecs away - further out than Procyon! I know it's a long way out from the Sun but not that far out! But it's true that the gravitational bonding holding it all together is extremely weak, and the least nudge from a passing object (Procyon, if you like) would perturb a comet out of its orbit and start it tumbling towards the Sun. Which it would then take hundreds of thousands of years to reach.

I think most people should expect to see about three or four really spectacular comets in their lifetime, on average. The brightest in the 20th century was reputed to be the Daylight comet in 1910, but maybe Ikeya-Seki briefly outshone it.

Of course Pete, Far to big a number, and I've modified it.

No excuse, I just failed to check the number I typed.

Surprising the difference a nought makes.

Ron.

[Star child]

Everyone seems to rember Hale Bopp, but what about the other great comet that happened a year before, im talking of comet Hyakutake, ok so it wasnt as spectactular as Hale Bopp but it was my first comet and it was quite impresive, bright enough to see in a not tottaly dark sky, and it was so close to us you could see its movement across the stars in just 30 mins it covered an area of the full moon, so heres to you my first comet, i wont forget you!