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Space and Astronomy Thread |
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#2226 |
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How soon can we see them from the UK? |
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#2227 |
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Join Date: Mar 2007
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Very impressive. I was a bit confused in the description where they said the tails point approximately towards the recently set Sun. However, everything seems in order.
How soon can we see them from the UK? |
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#2228 |
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Join Date: Jun 2006
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Very impressive. I was a bit confused in the description where they said the tails point approximately towards the recently set Sun. However, everything seems in order.
How soon can we see them from the UK? |
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#2229 |
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Join Date: Nov 2008
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Thanks, I'll have to find a nice clear horizon for the end of next week.As for today, there is a well placed -7.8 magnitude Iridium flare at 17.47 and a clear sky here in SE13, which makes a change. |
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#2230 |
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Join Date: Apr 2005
Location: Crawley, West Sussex
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I see that the BBC have got their graphic wrong in this article about the comet. They are showing a track with the tail towards the Sun instead of away from it.
It is the old misconception that, if it is going in a particular direction, the tail must trail behind. |
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#2231 |
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Join Date: Jun 2010
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I see that the BBC have got their graphic wrong in this article about the comet. They are showing a track with the tail towards the Sun instead of away from it.
It is the old misconception that, if it is going in a particular direction, the tail must trail behind. Technically with the sun setting in the west and the comet following the sun (in it's movement across the sky relative to the observer), it makes sense for the tail to be displayed as roughly going from west to east at that time of the evening, as in the graphic. Your average BBC reader of those articles is unlikely to be that clued up about orbital mechanics and the likes. Some nice shots here taken by an amateur from a southern hemisphere location. http://stargazerslounge.com/topic/17...mount-stromlo/ |
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#2232 |
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Join Date: Apr 2005
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Technically with the sun setting in the west and the comet following the sun (in it's movement across the sky), it makes sense for the tail to be displayed as roughly going from west to east at that time of the evening, as in the graphic.
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#2233 |
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Join Date: Jun 2010
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In that graphic, the western horizon is somewhere below the bottom of the image with the Sun somewhere below that, so for the tail to be going west to east, it should be going towards the top of the image, not the bottom as shown.
Ideally they should've showed a procession of mini comets marking out the days instead of the one blob with a haze behind it. |
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#2234 |
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Well mail them then lol...
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#2235 |
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Join Date: Jun 2010
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I already had before I posted here.
![]() Must admit it's a nasty looking graphic before we even get to the comet!! I find most people with star maps like that get confused quite easily as they don't really show magnitude properly. A lot of the 'quick user guides' etc are a little lacking and don't feature relative scale well enough. They should've just ripped an image off heavens above and asked for permission etc. |
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#2236 |
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Join Date: Dec 2004
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I see that the BBC have got their graphic wrong in this article about the comet. They are showing a track with the tail towards the Sun instead of away from it.
It is the old misconception that, if it is going in a particular direction, the tail must trail behind. The ion tail does indeed point away from the sun, but the dust tail points back along the orbital trajectory. |
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#2237 |
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Haven't you added you own misconception to the mix? Comets have two tails, not one.
The ion tail does indeed point away from the sun, but the dust tail points back along the orbital trajectory. |
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#2238 |
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Join Date: Jun 2010
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You might find this interesting relative to our discussion
http://spaceguard.rm.iasf.cnr.it/NSc...t/com-tail.htm |
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#2239 |
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Join Date: Dec 2004
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Yes, but the main tail, that most people see, points away.
Are you saying this is atypical? |
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#2240 |
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I can clearly recall seeing both tails of Hale-Bopp, and I also recall that the yellow dust tail was the most prominent of the two.
Are you saying this is atypical? |
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#2241 |
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Join Date: Dec 2004
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I too clearly remember Hale-Bopp (for weeks on end) and the main impression to the naked eye was of a tail that pointed away from the Sun as expected.
This paper states that the ion tail didn't become visible until sometime after the dust tail: "We photographed Comet Hale-Bopp from Sept. 1996, to April 1997, as it approached the Sun, moving from 3.5 AU (1AU = average Sun-Earth distance, or 150 million kilometers) in towards its perihelion at 0.91 AU[3]. During this time, the comet evolved from sporting a short fan-shaped dust cloud,into a twin-tailed object." However, they also talk about comet Hyakutake having only an ion tail: "Unlike Comet Hale-Bopp, Comet Hyakutake displayed only a plasma tail (indicating that it was relatively dust-free)" So clearly not all comets are the same. Hale-Bopp also had a third tail, consisting of neutral sodium atoms, that took up an intermediate position between the ion and dust tails. I don't think that could be seen without appropriate instrumentation. |
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#2242 |
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The images found using google all seem to show a blue ion tail that is rather less prominent than the dust tail (though both are easily seen). So unless this is a mere photographic artefact, and my memory is faulty, I think I'll stick with my recollection!
This paper states that the ion tail didn't become visible until sometime after the dust tail: "We photographed Comet Hale-Bopp from Sept. 1996, to April 1997, as it approached the Sun, moving from 3.5 AU (1AU = average Sun-Earth distance, or 150 million kilometers) in towards its perihelion at 0.91 AU[3]. During this time, the comet evolved from sporting a short fan-shaped dust cloud,into a twin-tailed object." However, they also talk about comet Hyakutake having only an ion tail: "Unlike Comet Hale-Bopp, Comet Hyakutake displayed only a plasma tail (indicating that it was relatively dust-free)" So clearly not all comets are the same. Hale-Bopp also had a third tail, consisting of neutral sodium atoms, that took up an intermediate position between the ion and dust tails. I don't think that could be seen without appropriate instrumentation. |
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#2243 |
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Join Date: Jun 2010
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Guys you'll argue each other into the ground on this....let it go!!
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#2244 |
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Join Date: Apr 2005
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Guys you'll argue each other into the ground on this....let it go!!
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#2245 |
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Join Date: Jun 2010
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Is anyone going to attempt to image it? Be interesting to see the DS'ers can do!
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#2246 |
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Join Date: Jul 2012
Location: Reading
Posts: 3,604
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I see that the BBC have got their graphic wrong in this article about the comet. They are showing a track with the tail towards the Sun instead of away from it.
It is the old misconception that, if it is going in a particular direction, the tail must trail behind. Have they seen the weather forecast for the next four days? This comet will have to be ****ing bright. |
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#2247 |
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Join Date: Jun 2006
Location: ♫ At The Keyboard ♫
Posts: 11,556
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Maybe some big news coming from the Curiosity rover next week?
http://spaceref.com/mars/curiousmars...-analysis.html |
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#2248 |
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Join Date: Jul 2002
Location: Pembrokeshire.
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ProfBrianCox: RT @PeoplesAstro: You can see Comet #panstarrs in west after sunset. Tomorrow night it will sit just below the Moon and above Mars http: ... http://owl.li/2voGrt
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#2249 |
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Join Date: May 2010
Posts: 452
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*jumps up and down*
I saw Pan-STARRS! From my back garden, with the naked eye! Awesome! I thought it'd be visible (with difficulty) from tomorrow! ie, I wasn't even looking for it, so I was stunned to see it so easily, and the double tail it had was beautiful. http://imageshack.us/photo/my-images...311181802.jpg/ This one's a zoomed-in view. http://imageshack.us/photo/my-images/4/177pl.jpg/ |
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#2250 |
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Join Date: Jun 2009
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*jumps up and down*
I saw Pan-STARRS! From my back garden, with the naked eye! Awesome! I thought it'd be visible (with difficulty) from tomorrow! ie, I wasn't even looking for it, so I was stunned to see it so easily, and the double tail it had was beautiful. http://imageshack.us/photo/my-images...311181802.jpg/ This one's a zoomed-in view. http://imageshack.us/photo/my-images/4/177pl.jpg/ Wow, that's much clearer than I was expecting. |
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