Comet Ison.....latest

[loveoneanother]

I was catching up on the news about Comet Ison last-night (Thursday October 17th) and came across the latest release from the Hubble team who are observing the comet.

(I can't see anything about it posted on any of the other 'Ison' threads but if any of the Avalon admin. team or moderators think it belongs on one of the other Ison threads please feel free to move it.)

The following extract that i have highlighted in bold is taken from the Hubble Blog page and i've also added the accompanying video from the "Hubble Hangout' team in which the latest picture of Comet Ison and other related issues are discussed (the 'comments' section of the video is also interesting too ).

(This is my first ever 'Comet' observation so please excuse the over-enthusiasm.....i'm a comet virgin if you will and think it's all very exciting !)

The photographic proof is in: Reports of Comet ISON’s demise were greatly exaggerated. Contrary to some pessimistic predictions, new Hubble data show the comet still trucking along as it falls inward of Mars and ever closer toward the Sun.

This new image, recorded by Hubble on October 9, combines long exposures taken through blue and red filters. Over 29 minutes, Hubble switched back and forth between these filters as it tracked Comet ISON across the sky.

What little color ISON has is due to differences between a comet’s coma and its tail. The tail, comprised of dust particles torn away from the comet by the gentle pressure of sunlight, appears redder because dust grains reflect redder light. The coma, by contrast, is bluer. It doesn’t contain much dust, just gas sublimating from the comet’s surface.

The comet’s nucleus, estimated at less than 2 kilometers in diameter, is tiny even through Hubble’s eagle eyes. A single pixel in this image spans 55 km of comet, making the nucleus un-resolvable at this separation (about twice the Earth-Sun distance). Still, careful study of this image suggests the nucleus is almost certainly still intact — the coma spreads out evenly from a single point, which we wouldn’t see if ISON were falling to pieces.

In fact, the symmetry of ISON’s coma suggests that the comet’s entire Sun-facing surface is feeding the coma — no jets of gas have been spotted in this image. Without a jet to spin it around (see: WALL-E & Gravity, “fire extinguisher”) ISON likely isn’t rotating much. This suggests an exciting potential future: Perhaps there’s a “dark” side of ISON, which won’t have ever seen the light of day until the comet goes around the Sun. If such pristine material still exists, ISON may become more active than we currently expect.

One mystery remains. How has ISON — humble, patient, surprisingly average Comet ISON — sparked predictions that run the gamut from “bright as the full moon” to “disintegrating as we speak”? Simply put, ISON peaked early. When it was first discovered, way out past Jupiter, ISON was really bright.

Extrapolated, those first data points made ISON look like it would shine even more as it got closer — and when it didn’t, the coverage seesawed back toward calling ISON a total bust.

According the University of Maryland’s Mike A’Hearn, that’s the curse of “dynamically new” comets, including the infamous Kohoutek. In the first four billion years of its life, ISON never once strayed into the protective umbrella of the solar wind. Without that protection, the comet’s surface was bombarded by galactic cosmic rays: high-energy particles from exotic places like the rims of black holes. That irradiated surface became fragile, volatile — only a little heat from the Sun was enough to sublimate a huge amount of gas, causing ISON’s brightness to spike early on. This is just one interpretation — Karen Meech from the University of Hawaii argues that an outburst of carbon monoxide better explains that early brightness — but the consequences still stand. ISON, like a burnt-out former child actor, has been unfairly judged by the benchmark of its own prodigious standard.

So here we see a dichromatic ISON, still in one piece, still en route to the Sun. We hope it survives its brush with destiny, heat, and gravity — at least long enough to light up our pre-dawn skies this December. What more can we ask of it?

Join us at 4 p.m. EDT on Thursday, October 17, for a live Hangout with Hubble comet scientists to discuss the new image and latest research findings about ISON.

http://hubblesite.org/hubble_discoveries/comet_ison/

Source: https://youtube.com/watch?v=YeN3W3WfEn4

[Lifebringer]

Thank you so much. Valuable input on the language of scientist on the this event.

My book needs more ends tied, and everything that's happening/revealed, is a help.

Sometimes my educational level although a college graduate, doesn't exceed to the scientific vocabulary and Space.com, NASA, and others are a big help. I can't translate some of the other countries language and am just using pictures in the videos which take longer than a read.

[Lifebringer]

18:20-22 shows a planet next to the comet clearly reflective off the comet's light on the opposite side facing away from the sun. So here it comes peeps. There's supposed to be 7 orbiting planets around the dwarf, and I think we may have seen the first one as it goes around and is present in the comet's light that is in the lead.

[conk]

http://worldufophotos.org/site/#/gal...ufo-following/

[ghostrider]

I love the path of these things , far out in the cosmos , it could go anywhere , but it heads straight for our sun , then is supposed to make a loop around and head straight back out ... completely different than planets which orbit in an oval path ... ya know , what are the odds of this ??? our nearby planets stay in orbit around the sun but this tiny thing somehow is able to overcome the entire gravity of the Sun and pull away and head back out from whence it came ...

[KiwiElf]

I think they call it the "slingshot effect"

[loveoneanother]

Help.....i'm feeling 'astronomically' challenged

I wonder if one of my fellow Avalonians can assist me in my understanding of some of the latest data related to Comet Ison ?

I've been trying to take the advice given by Mr.Ryan on another thread to learn some basic astronomy, which i've been attempting to do but unfortunately (and inevitably) i've got myself a little bit confused

My current area of confusion is around something called Minimum Orbit Intersection Distance or MOID. According to the latest Comet Ison data released by JPL (Jet Propulsion Laboratory) here.....

http://ssd.jpl.nasa.gov/sbdb.cgi?sst...og=0;cad=0#orb

.....it states in the Orbit Determination Parameters section that at the solution date (date of orbit determination) on 2013-Oct-15 11:12:07 the EARTH MOID (Minimum Orbit Intersection Distance) was .0231487 AU.

I didn't really know what that AU figure means in terms of distance so i used an online converter to convert the figure into Kilometres and then Miles and the AU figure works out like this :

.0231487 AU = 3,462,996 Km or 2,151,805 miles

(Ok.....fair enough me thinks.....it is what it is etc.....now what ?)

After further reading about MOID it became clear that there are two possible MOID related figures you can get. There is plain old MOID which gives you the distance at which two orbits cross (basically how far apart the orbits are when they cross), then there's an MOID which can be prefixed by the name of a planet or some other object ie. in this case EARTH MOID. The distance figure produced with this type of MOID is actually the distance between the two objects (not, as i first understood it, as the distance between two orbits which to my mind is a subtle yet important difference !).

So.....at the time of the 'solution date' (Oct.15th).....the nearest predicted distance the Earth and the Comet would get to each other would be 2,151,805 miles (i'm a bit of an old fossil and prefer thinking in terms of miles ).

(Fair enough.....sounds like a fair distance to me......ok.....move along now.....nothing to see here me thinks!)

I usually get to a point when i'm trying to learn something new when i've simply got to leave it for a while and do something else because i start to get that 'BRAIN FULL' feeling so off i went to catch up on who's saying what on YouTube (nice to let someone else do the thinking for five minutes ).

As i'm 'on one' at the moment with regards anything to do with Comet Ison, these are the type of videos i'm mostly looking at (i'll put one i came across at the end of the post which i thought was really cool !).

One of the videos i watched was this one by SuspiciousObservers.....

Source: https://youtube.com/watch?v=qjNvv4de9x8

.....the whole video is interesting but what caught my eye in particular was the screenshot of the JPL Orbit Determination Parameters for Comet Ison which appears at about 11 seconds into the video.

Of course, my head was still full of what i'd been reading earlier and i recognised straight away the figures were different without really understanding what i was looking at. According to this screenshot of the JPL orbital data, on October 14th at 17:14 the EARTH MOID was .0231734 AU ( 3,466,691 Km or 2,154,101 miles).

A quick back of the envelope calculation told me that in the period of approx.16 hours Comet ISON had gotten 2,296 miles closer to the Earth. For my own amusement, i tried to work out how much closer the two objects would be when their orbital paths crossed on about November 1st (?) and came up with a figure of 895,440 miles closer (2296 divided by the 16 hours to get the miles per hour then multiplied by 390 hours to the end of the month).

I'm probably missing something here and i did say i'd gotten myself confused a bit but i think it's possible the Earth and Comet Ison could be as close as 1,256,365 miles apart when their orbital paths cross. Apparently, one LD (Lunar Distance) is about 238,855 miles which means that Comet Ison could be about 5 LD at its closest on its inbound journey.....sounds pretty close to me !

I suppose the question has to be how close do these things need to be before they start having an effect (if any) on the Earth and it's systems ?

Sadly dear reader that's not quite the end of my musings

While i was looking at all this in total bewilderment a light-bulb went on and it suddenly occurred to me that all this is based on the EARTH MOID . The next question surely has to be what is the actual MOID ? Exactly how close do the two orbital paths of the Earth and the Comet get ? What is the MOID (anyone) ? Surely knowing this figure will tell us how close the Earth will get to the comet tail as we swing towards it ?

Ok.....i think i've probably done myself (and everyone else) in with all this but just putting it out there is all. Hopefully someone can follow my thought processes and highlight any flaws in my thinking of which i'm sure there are many

(While on my comet travels i came across this really neat blog that has some great graphics to help with the timeline of the comets journey through the inner solar system. I've highlighted in bold the introduction to the site which will hopefully encourage you to look into it some more with a link to the site to follow )

Thanks everyone.....i think this is the biggest post i've ever done.....i'm now off to lay down in a darkened room

The ISON atlas

There are lots of blogs and websites about Comet ISON now, as you’ll already know if you’ve done a Google search for “Comet ISON”, but if all you want is somewhere to go to tell you and show you, with no fuss, where to look for Comet ISON in the sky later this year, then this is the place.

If you’re wanting more than this – if you want the scientific background to the comet, tips on how to photograph it, advice on how to observe it, slightly ranting diatribes against the nutters and fruit loops who have tried to hijack Comet IOSN and turn it into the latest “The End is Nigh!” tale of doom, I have a proper Comjet ISON blog you might like to visit…

http://waitingforison.wordpress.com/

But back to basics. Here you’ll just find lots and lots of simple finder charts which will help you locate Comet ISON in the sky later this year. They were created using the popular “Sky Safari” Android and iOS phone app, which I can’t recommend highly enough. If you are a “smartphone” or tablet owner witrh an interest in astronomy then really you need to download the app as soon as you’ve finished reading this page. There are several different versions of the app, of increasing complexity and, of course price, but the free one will be invaluable to you if you’re wanting to follow Comet ISON as it moves through the sky later this year.

A quick note on the charts. They look very dramatic don’t they! Calm down. At the moment, NO astronomical software can accurately show, or predict, the lengths of comet tails, they just can’t. So if you see a chart here and think “Wow! Look at the length of that tail!!! I can’t WAIT to see THAT!!!” please be aware that it probably won’t look anything like that in reality! Please, just use the charts as rough guides to figure out where, and when, to look for the comet in relation to your local horizon and the Moon and other objects in the sky.

The tails shown on these charts should only be thought of as rough guides to the direction the tail might be pointing in at the time; we won’t know how impressive Comet ISON is going to be for months yet.

Having said that, I hope and think you’ll find these charts useful in planning ahead when and where to look for, observe and maybe even photograph Comet ISON later this year. It might be the best comet for centuries, or it might be a lot less impressive than that, we just don’t know yet. But we do know where it will be in the sky and this blog’s aim is simple – to help YOU find Comet ISON in YOUR sky later this year.

By the way, if you’ve already had a peek at some of the charts and thought “They’re tiny!” don’t panic. Clicking on them will enlarge them.
One final thing. Please note that these charts are “drawn” for mid-northern latitudes, so if you live a lot further north or south you might need to take that into account, ok?

Right, introduction over. Go and explore the Atlas and its charts, and start planning where, and when, YOU will be able to see Comet ISON.

http://isonatlas.wordpress.com/#respond

Source: https://youtube.com/watch?v=TULT9QUevnQ

[loveoneanother]

According to the latest data released by the Jet Propulsion Laboratory (JPL), Comet Ison has moved 10,755 miles closer to the Earth at it's closest approach based on observations taken up to October 21st 2013.

http://ssd.jpl.nasa.gov/sbdb.cgi?sst...g=0;cad=0#elem

This now puts the total distance between Comet Ison and the Earth at 2,141,051 miles at it's closest approach or 0.0230330 AU.

According to my research, Comet Ison (if it was classified as an asteroid or other near earth object) would be classed as Potentially Hazardous. Any Near Earth Object (NEO) with an AU of 0.05 or less is considered Hazardous.

Looking at the historical records for close comet approaches to the Earth, Comet Ison (if it survives it's journey around the sun) would be right up there as one of the closest comets there has ever been.

Have a look for yourself by clicking on the following link. The important column is the one on the left that shows the AU distance and bear in mind the current AU of 0.0230330 being given by JPL :

http://www.minorplanetcenter.org/iau...estComets.html

I don't know.....what am i missing here ? If someone can tell me how i might be getting this all wrong i would very much appreciate it. Almost everywhere i look, most people are saying the comet will be 30+ million miles away from the Earth at it's closest

Thanks for reading everyone.....loveoneanother

(A description of what EARTH MOID means :

http://en.wikipedia.org/wiki/Minimum...ction_distance )

[KiwiElf]

Any potential risk is what may lie in the tail of the comet as we pass throught it... twice. Possible debris, which if it's ice, will evaporate in Earth's atmosphere. If its composition is made up of something other than ice, then possibly we may get something a little more significant: certain elements or chemicals evaporating in the atmosphere (which have been blamed in the past for the black plague, flu's, outbreaks ... you name it. Nothing conclusively proven on that tho). There's speculation that there are other objects or a debris trail near or following ISON (the latter may be because that's the area of space we happen to passing through at the time = possible meteorite strikes. All these potential hazards are really there daily.

As for the "objects" or UFOs which are claimed to be orbiting ISON, that has not really been proven as yet - just another YOUTube video - which could be faked - claiming to be from the Chinese Space program.

My bet is if anything, it may be a visually impressive comet and tail, at this time.

If its estimated closest proximity to the Earth will be as given above, then it's still almost 8-9 x the distance from Earth to the Moon, the comet itself is unlikely to cause any threat. (The Moon is 405,718 km from Earth approx (252,101 miles).

ANALOGY: It would be like a small, Radio Controlled toy speedboat (ISON) zipping past the Queen Mary (Earth): the wake of the Queen Mary (Earth) might affect the speedboat (gravity), but have virtually no affect the other way around.

The stronger "magnet" in any case, is the Sun.

BTW, 1 x AU or Au (au) means Astronomical Unit. Now defined as exactly 149,597,870,700 m (92,955,807.3 mi) or 149,597,871 kilometers, or roughly the average Earth–Sun distance.

[Valle]

Nice Ison 3D-visualisering
http://www.solarsystemscope.com/ison/

[loveoneanother]

Here's the latest couple of blogs from the Comet Ison Observing Campaign (CIOC) team which are an interesting read (is there a guarded admission in the first linked blog about the connection between comets and solar activity?) :

http://www.isoncampaign.org/karl/comets-in-solar-wind

http://www.isoncampaign.org/why-does-ison-look-green

Kiwi-elf.....thanks for your earlier post.....you gave me plenty to think about that's for sure.....I've been busy researching comet-tails ever since you posted (good timing too in helping me to understand some of what is being said in the first of the above linked CIOC blogs)

Can i ask you about something you posted ?

You said : "Any potential risk is what may lie in the tail of the comet as we pass through it.....twice."

I'm speculating wildly here but isn't there a third, earlier pass of the comet's 'gas' tail through the Earth as the comet swings around the sun below the ecliptic. The only reason i'm thinking along these lines is because i've read that the 'gas' tails of comets have been know to exceed 1AU (the distance between the Sun and the Earth) and because of the shallow angle at which ISON goes down through, around and back up through the ecliptic.

Isn't it possible (more speculating again) that if ISON survives it's journey around the Sun and previously unexposed surfaces begin rapid out-gassing, there will be a super-charged 'gas' tail sweeping around in an arc just below the ecliptic plane on which the Earth is sitting before the comet re-aligns itself for it's outward journey away from the sun ?

Added to the current increase in Earth directed solar activity, wouldn't an extended Earth directed 'gas' tail put extra stresses on the Earth's magnetosphere and subsequently the Earth's atmosphere ?

I may have this all wrong (more than likely) for whatever reason so all i can say in my defence of this wishy-washy type of thinking is i'm not scientifically trained or scientifically educated in any way and all i'm really doing is thinking out loud.

Any pointers will, as always, be most appreciate and once again my thanks for a very thought-provoking post

(As an addition, i'd like to offer you an anthropocentric analogy along similar lines to the geocentric analogy you gave in your earlier post with the toy speedboat and the Queen Mary.

Imagine a celestial airport floating in space which is at the hub of 36 equidistant runways which are all pointing in to the centre. I feel like i'm walking across runway Number 1 around the very outer perimeter of the airport heading for runway Number 2, aware that somewhere on one of the runways ahead of me, the biggest jet-liner i'm ever likely to see is about to make a fly-by.

Being a celestial airport it has no landing strips as such but that doesn't matter because all the jet-liner is scheduled to do is fly in towards the airport, swing around the back of it then attempt one of the trickiest manoeuversever in the space-flight handbook, the reverse exit, flying out backwards over the same runway it came in on.

As an observer of this once in a lifetime event, all i need to be mindful of, as i continue my steady and relentless journey around the airport perimeter, is the jet-wash and the pollution

[KiwiElf]

Hi Loveoneanother,
Thank you - I am very much an amateur when it comes to astronomical things, and am still on (a steep!) learning curve myself

ISON is a bit of a question mark in terms of what it will do; using Valle's example above with a bit of modification to incorporate Earth's position at those points in time, "apparently" we fly through the tail of ISON as it's going in, and again - IF it survives it's slingshot around the sun - as its going back out again. (Like we're sort-of travelling at right angles to the path - ie, let's imagine the speed boat is smoking, leaving a wide trail of smoke that hangs around a while too - and has crossed the Queen Mary's bow to the right and then does a U turn - (more like a rounded "V") and crosses her bow again, heading to the left. We pass through the smoke trail twice, so to speak. (Not sure about 3 x - I'm still learning about that one as well!)

I strained my eyes this morning at 5:30 am just as dawn was breaking but unfortunately, low haze prevented anything on the horizon to about +10 degrees being seen. Regulus & Mars were easily visible and serve as good "pointers": (to our N-E roughly). From our Point of View, ISON now lies down and to the right of Mars, (Regulus is above and to the left of Mars, almost at a 45 degree angle). ISON is at a slightly flatter angle if you drew a line through Regulus to Mars and about half the relative viewable distance again (in 2D) between the two. Relatively speaking, ISON will continue to move further to the right on that path (toward the Sun, which is just out of view to the right of the frame) as time progresses, before doing its turn.

PIC (Below) - Frame Grab from Redshift 7 Planetarium software at 5:50 am our Local time this morning.



Click to enlarge - ISON is between the two bright green markers, below & to the right of Mars. Keep in mind, it was dawn here at this time so many of these stars were not visible

The orange type data in the top left corner gives my viewing position (Auckland, NZ). (You might just be able to make out Jupiter's position under the type)
The wide info box up to the right is ISON's position at the time.
Recommended software (or similar) to have BTW

http://astronomy-software-review.top...ft-review.html

With regard to your other questions re impact on Earth, I would be guessing at best. Recommend someone with much more knowledge than I answer those for you (Amzer Zo - where are you, buddy? - I would imagine very little affect from the comet or tail itself, other than what I said previously, but who knows?)

Your airplane/runway analogy is also most thought provoking, but I think it would be more akin to a "smoking RC model airplane" in this case in terms of relative size and "wake"?

[KiwiElf]

Loveoneanother - As you're interested in comets, there may actually be two comets visible on the 14th November; This frame grab projects where ISON will be visible in our end of the world (at [1]), but a second comet, ENCKE, will also be possibly visible to the right and near the horizon at 05:20 our local time [2] - it will be closer to the Earth than ISON, but probably the glare of the Sun will make it too hard to "see". (This has got to be a first! - Two comets visible in close proximity!) Projected data for each is in the info boxes above.

PIC: Comets ISON & ENCKE - 14 November 2013 - 05:20 NZ Local Time - Click to enlarge



http://en.wikipedia.org/wiki/Comet_Encke

[MariaDine]

Comets are very important...but, what worries are the ever erratic asteroids....



ASTEROIDS names list -

http://www.nofs.navy.mil/festsci/list/astname.html

-------------------------------

..........a place to start searching
Namasté

[Snowflower]

I think it is possible that Ison is the blue kachina and the incoming object so many people are seeing in the southwest sky is the red kachina. Ison is blue. The other one is reddish when observed thru telescope. It also is not round, but appears to be winged - in looks. It is planetary size, not plane size. Historical accounts cite a "winged destroyer." I can't remember - is the blue the destroyer and red the purifier or visa versa in Hopi teachings? Anyway - no one has any idea what that red thing is, how long it will take to get here, where "here" will be - and NASA is still pretending it isn't there.

[Wind]

Posted by Snowflower (here)
I think it is possible that Ison is the blue kachina and the incoming object so many people are seeing in the southwest sky is the red kachina. Ison is blue. The other one is reddish when observed thru telescope. It also is not round, but appears to be winged - in looks. It is planetary size, not plane size. Historical accounts cite a "winged destroyer." I can't remember - is the blue the destroyer and red the purifier or visa versa in Hopi teachings? Anyway - no one has any idea what that red thing is, how long it will take to get here, where "here" will be - and NASA is still pretending it isn't there.

I've been thinking about the same thing. Blue Kachina is the final messenger and Red Kachina is the destroyer. Could Sun be the destroyer or will it be a different object like Planet X? Hard to say.

Latest image of Ison from amateur observer Bruce Gary, he has been studying it enormously.

[Sidney]

I found this video to be informative.

Source: https://youtube.com/watch?v=ZspLjRW702c

[loveoneanother]

I've been trying desperately not to let my posts turn into the 'watch the video and listen to what someone else thinks' type of posts because i want to do my own research and share what 'i think' for a change but sometimes you come across something that just blows you away and it has to be done

I think i spent the whole time watching the following video holding my breath (i don't recall breathing at all which usually means i'm pretty focussed on what i'm seeing and hearing which is a good sign) and when it got to the part where the guy mentioned noctilucent clouds looking blue i thought wow, does that bit of info tie in with what some of the previous posters have been saying about the blue kachina ?

I can't say i know much about the blue kachina thing but even so, after the posts earlier about it, i started wondering how was it possible for our ancient ancestors to see something blue in the sky when they didn't have the benefits of the technology we have today ? I mean, i've never looked up and seen a blue object in the sky so how was this possible ?

I then got to thinking maybe it was something caused by atmospheric 'pollution' (or at least whatever the ancient equivalent to pollution was back then) and started thinking about volcanic eruptions sending smoke into the atmosphere affecting the colour spectrum or things burning on the ground like forest fires causing the same phenomena. I even started wondering whether it was the ancients themselves that altered the composition of the atmosphere somehow because i'm guessing there was a lot of burning of all sorts of weird and wonderful stuff going on all over the place ?

Unfortunately for me though, without digging into this type of thinking more thoroughly, all i could do was put such thoughts on the back-burner as a maybe and leave it at that !

The whole noctilucent cloud thing smacked me straight between the eyes and i thought that's it surely ? If an 'unfamiliar' object is moving across the sky close to the Earth's atmosphere and noctilucent clouds are blue, wouldn't that make the passing object look like it was blue too ?

Could be.....right ? Or is this something else i'm getting completely wrong ? I dunno, maybe i should forget about the 'thinking for myself' bit after all !

Here's the video anyway. I hope someone gets something from it like i did.....wow is all i can say

Source: https://youtube.com/watch?v=imduPbBbt-0

[greybeard]

The ancients knew so much about movement of planets and stars I sometimes think we are just starting to catch up.

Chris

[loveoneanother]

Posted by KiwiElf (here)
Loveoneanother - As you're interested in comets, there may actually be two comets visible on the 14th November; This frame grab projects where ISON will be visible in our end of the world (at [1]), but a second comet, ENCKE, will also be possibly visible to the right and near the horizon at 05:20 our local time [2] - it will be closer to the Earth than ISON, but probably the glare of the Sun will make it too hard to "see". (This has got to be a first! - Two comets visible in close proximity!) Projected data for each is in the info boxes above.

PIC: Comets ISON & ENCKE - 14 November 2013 - 05:20 NZ Local Time - Click to enlarge

Attachment 23362

http://en.wikipedia.org/wiki/Comet_Encke

Hello Kiwi-elf : Thanks for your contributions to this thread. I'm trying my best to keep up to date with all the latest Comet Ison news and post anything of interest here but it's not easy when other areas of life are demanding attention

I'm sorry to lay my astronomical ignorance on you again but could you tell me whether the amateur astronomy folks also do orbital calculations as part of their hobby or is that sort of thing more technical in nature and is best left to the 'professionals' ? I've looked at some amateur astronomy blogs and most seem to focus on the comet itself looking at things like the brightness, the coma, the tail etc.

I'm wondering how we would get the updated orbital calculation for Comet Ison if the US government decides to have another shutdown as the comet goes around the Sun ?

It has been said by Mr.Ryan and others that the amateur and backyard astronomers have their collective eyes on Space and any or all of them would flag up anything out of the ordinary going on 'out there'. Would that also be true for something like a change in trajectory of a comet like Ison or are we at the mercy of the likes of JPL with that one

I think what i'm getting at here is if, for whatever reason (solar flaring?), NASA shuts down again as Comet Ison goes around the sun (as happened when the comet went by Mars), would those in the amateur astronomy community be able to re-calculate whether there have been any significant changes in Ison's orbital path and trajectory or would it be more a case of 'observing' the night sky to figure out what changes if any have occurred ? I'm also thinking as the comet is expected to be a naked-eye object if it survives it's journey around the Sun, seeing a big long tail is good, seeing a short stubby tail not so good.....what do you think

As you can probably guess, i still haven't been able to resolve this EARTH MOID business and still don't know why the latest orbital data up to October 28th has an Earth Distance of 0.429 AU (39,878,041 miles) and an Earth MOID (Minimum Orbit Intersect Distance) of 0.0231545 AU (2,152,345 miles) ? Why are these two figures so far apart ? What is being measured here ?

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=ison&orb=1

Amazing photo by Damian Peach to finish