Comet C/2012 S1 ISON

Alles puur natuur nier ;-)
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baphomet
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vr 22 nov 2013, 21:49

Ja ik zag het net ook al voorbij komen op GLP Combi...

Net als onderstaande filmpje trouwens:

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vr 22 nov 2013, 21:51

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vr 22 nov 2013, 22:44

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vr 22 nov 2013, 22:46

ISON, Encke, Mercury, and Home

Yesterday, amateur astronomers online were very quick to point out that comet ISON had entered the field of view of the NASA STEREO-A Heliospheric Imager 1 ("HI-1A") camera. It wasn't much to look at, as we only had available our low-resolution "beacon" data, but nonetheless you could clearly see a bright streak on the left-hand side of the HI-1A images. It was nice and reassuring to see the comet arrive in the camera but we had been expecting it for a long time, and indeed had been watching it in the wider field "HI-2" camera on that spacecraft since October 11, 2013.

When our STEREO imagers first caught sight of it, the comet was barely registering magnitude 12 on the brightness scale, and many astronomers were understandably feeling edgy as it labored slowly in it rate of brightening. But just over a week ago, comet ISON suddenly and spectacularly began to live up to our lofty aspirations, experiencing a dramatic outburst that saw it brighten from a 7th magnitude "green fuzzball" into one of the most visually stunning comets we've seen in years, now shining brightly at 3rd or 4th magnitude!

The stage was set, and timing couldn't have been better for ISON to make its appearance into the higher-resolution HI-1 camera on STEREO-A - and that's what I'm excited to share with you now. But of course, no great scene in space is complete without a cast of supporting characters, and ISON has chosen a great set of companions for this scene. Click on the below image to watch something pretty awesome!

Afbeelding

I hope you appreciate that there's a lot of awesome happening in that short animation! So much so, actually, that I could write pages of comments about it. However, I'll try for brevity here...

First thing you're probably saying: "well that was rather short! We want more!!". Yep, sorry. Come back in a couple of days time and you'll have a lot more to look at, but for now all we have are those few frames. But just in that brief period I hope you can see what we might have in store for you...

What we're looking at here is a cropped section of a 20-degree field of view, taken from a spacecraft that is far from Earth. We can see not only comet ISON entering the field of view but also Comet 2P/Encke, Mercury and that little place we like to call home!

The dark "clouds" of stuff you see coming from the right are density enhancements in the solar wind, and these are what are causing all the ripples you see in comet Encke's tail. I can pretty much promise you that we're going to see ISON's tail doing that in a couple of day's time, but on a much larger scale! (ISON is closer to STEREO-A than Encke is - this has little to do with relative sizes of the comets). Indeed, these kinds of solar wind interactions are exactly what I wrote about a couple of weeks ago, and they give us valuable information about solar wind conditions near the Sun.

And this leads me very nicely to the last - and to me most exciting - thing I'll say for now (brevity, remember...).

Notice the motion of the two comets. Notice the direction Encke is moving in, and then the direction ISON is coming in at. Then note that ISON is moving quite a bit quicker than Encke (both true in reality and because ISON is closer to the camera). See where I'm going? Or where the comets are going??

No they're not going to hit each other - in reality they are millions of miles apart - but as seen from the STEREO-A spacecraft, they are going to get very close! How close I don't know. Tomorrow I hope to give you that answer but it involves math and software, and it has been a long day. But regardless, we are probably a couple of days away from seeing two comets almost side-by-side in that camera, with long tails flowing behind them in the solar wind. To say that such an image will be unprecedented is rather an understatement.

Scientifically it's a huge bonus too! If you read my "comets in the solar wind" blog post, you'll understand why we're interested in watching those tail wiggles, and how they teach us about CME's, solar wind, etc. Basically the comets act like a remote probe or windsock, and we can watch their reaction to the solar outflows and learn what's going on. So now consider this: instead of having one solar probe, we now have two of them in slightly different locations in space. This is a very big deal. I was going to describe more about why, but this post has gone on enough for now.

This is the beginning now folks. I know we've said it could be the end for ISON, but in terms of excitement and amazing space-based images, this is the beginning. Don't stray too far from this website, particularly later next week. I've lived through one of these events before. It's stressful, chaotic, tense, sleepless, intense and often frustrating. It's also truly thrilling! Matthew and I will be on-hand to guide you through it all, so get your comfy chairs ready... it's all about to kick off!
Bron: ->> http://www.isoncampaign.org/karl/ison-e ... rcury-home
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baphomet
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vr 22 nov 2013, 22:48

Afbeelding
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vr 22 nov 2013, 22:51

Watch Live Webcast: Countdown to Comet ISON

We’re all watching what’s happening with Comet ISON, and today, November 21, 2013 Astronomy Magazine and Discover Magazine are hosting a “Countdown to Comet ISON” Google Hangout event, where the magazines’ expert editors will have all your comet questions answered. all the action starts at 20:00 UTC (3 pm EST). With ISON reaching its brightest this month, Astronomy Editor-in-Chief Dave Eicher, Discover Editor-at-Large Corey Powell and several others will discuss things like:
· When and where can you spot Comet ISON?
· How best to photograph the comet



We’ll post the video feed here when it goes live, but can also watch (and RSVP) at the G+ event page.
If you miss it live, you can watch the replay above.
Bron: ->> http://www.universetoday.com/106635/wat ... omet-ison/
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vr 22 nov 2013, 22:54

Anticipated STEREO observations of Comet ISON

Comet C/2012 S1 was discovered in September 2012 by Russian astronomers Vitali Nevski and Artyom Novichonok using data from the International Scientific Optical Network (ISON). For that reason, it is also known as Comet ISON. This comet is on a close encounter with the Sun on November 28, 2013 (Thanksgiving day in the U.S.), when it will pass at a distance of only 2.7 solar radii from the center of the Sun. Since Comet ISON was discovered so far out, beyond the orbit of Jupiter, and will pass so close to the Sun, many think that this could turn out to be a major comet. A number of NASA missions, including STEREO, are planning an observing campaign to observe the comet as it passes by the Sun. Below, we discuss the view that the STEREO observatories (plus SOHO and SDO) will have of Comet ISON as it swings by the Sun. On a separate page, we discuss the observing strategies and anticipated science of the STEREO instruments.

If Comet ISON works out as expected, the STEREO spacecraft should have a spectacular view. The movie below shows the geometry of the STEREO Ahead (red) and Behind (blue) spacecraft during the passage of Comet ISON (orange). The top panel shows the view from above looking down on the orbital plane of the planets (the ecliptic plane), while the bottom panel shows the view from the side. Note that the comet's orbital path is highly inclined to the ecliptic plane. As the comet approaches the Sun, it comes in at a fairly shallow angle, but leaves at a much steeper one, carrying it well above the ecliptic plane. If one only looked at the top-down view, it looks like the comet passes close to the Earth around the end of December, but the view from the side shows that this is not really the case.

Afbeelding

An even better way to examine the orbit of Comet ISON is to use this three-dimensional JAVA orbit tool provided by the STEREO SECCHI team.

The first STEREO telescope to see Comet ISON will be the large angle Heliospheric Imager #2 on the Ahead spacecraft (HI2-A). The first image below shows the projected day-by-day location of the comet in the HI2-A field-of-view from October 10, 2013, when it is expected to enter on the left side of the field, through November 23, 2013, when it is expected to leave on the right side of the field. Next to this is the comet's passage through the smaller HI1-A field-of-view November 21-28, 2013. Click on each image for a larger version.

Etc., etc., (zie bron voor meer)

Bron: ->> http://stereo-ssc.nascom.nasa.gov/comet_ison/
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vr 22 nov 2013, 22:55

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vr 22 nov 2013, 22:55

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vr 22 nov 2013, 22:56

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vr 22 nov 2013, 22:58

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za 23 nov 2013, 03:27

dubbelpost
[YES]Equality of Opportunity - [NO]Equality of Outcome
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combi
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za 23 nov 2013, 22:15

Komeet ISON nadert de zon met rasse schreden, voor zover kometen rasse schreden kunnen maken. Aanstaande donderdag 28 november beleeft ‘ie z’n perihelium, waarbij de komeetkern slechts 1,2 miljoen km langs het oppervlak van de zon zal scheren. Dat betekent dat de komeet, die afgelopen tijd ‘s ochtend voor dageraad aan de oostelijke hemel te zien was, te dicht bij de zon is gekomen om nog zonder risico waar te nemen. De laatste ogenblikken van komeet ISON voordat ‘ie de verlichte omgeving van de zon indook zijn vastgelegd vanuit het Teide Observatorium op Tenerife op de Canarische Eilanden, resulterend in onderstaande mooi timelapse video. Tijd om even gedag te zeggen tegen komeet ISON en hopelijk dat ‘ie begin december weer tevoorschijn komt!

http://www.nujij.nl/wetenschap/daaaag-k ... 3764.lynkx
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zo 24 nov 2013, 22:32

Since the first reliable orbital data was available, NASA-JPL has been saying Comet ISO was a hyperbolic comet, i.e. a probable one-time visitor to the solar system, due to leave and never return. The last automatic calculation on Thursday (designated as done by “Otto Matic”) maintained this finding. Notice that at the top there is the notation “Hyperbolic Comet”, the “a” value is negative, and the period is “n/a”:
from Thursday:

Afbeelding

But on Friday, a completely new set of parameters was issued, not automatic by produced by one Alan B. Chamberlin. Gone is the word “Hyperbolic”, the “a” value is now positive, and there is an orbital period listed as 400864.54 years. Moreover, even though the “last obs. used” is dated one day earlier, the there are 125 more observation being used. This puts the closest approach about 2200 miles closer to the Sun. This is only a change of less than 0.3%, from 726,298 miles to 724,090 miles, but still, it is very odd for it to crop up this late in the game:

Afbeelding

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=i ... og=0;cad=1
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