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Space and Astronomy Thread
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atg
05-03-2013
Originally Posted by HenryGarten:
“Picture of two comets Panstarrs and Lemmon


They peak in the next two weeks.”

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?
tvqueen1905
05-03-2013
Originally Posted by atg:
“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?”

Next week for panstarrs if i remember correctly
HenryGarten
05-03-2013
Originally Posted by atg:
“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?”

See PannStarrs
atg
05-03-2013
Originally Posted by HenryGarten:
“See PannStarrs”

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.
albertd
08-03-2013
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.
Elissa Richards
08-03-2013
Originally Posted by albertd:
“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.”

I think they're just trying to keep it easy to understand imo

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/
albertd
08-03-2013
Originally Posted by Elissa Richards:
“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.”

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.
Elissa Richards
08-03-2013
Originally Posted by albertd:
“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.”

Well mail them then lol....I know what you're saying, the proof reading is a little lacking. They've probably been confused by the motion of the comet rising through the constellations over the month. At least the they got the rough direction horizontally right (I've seen worse from them!), just not the diagonal orientation of the tail.

Ideally they should've showed a procession of mini comets marking out the days instead of the one blob with a haze behind it.
albertd
08-03-2013
Originally Posted by Elissa Richards:
“Well mail them then lol...”

I already had before I posted here.
Elissa Richards
08-03-2013
Originally Posted by albertd:
“I already had before I posted here. ”

Good man!!

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.
njp
08-03-2013
Originally Posted by albertd:
“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.”

Haven't you added your 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.
albertd
08-03-2013
Originally Posted by njp:
“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.”

Yes, but the main tail, that most people see, points away.
Elissa Richards
08-03-2013
You might find this interesting relative to our discussion

http://spaceguard.rm.iasf.cnr.it/NSc...t/com-tail.htm
njp
08-03-2013
Originally Posted by albertd:
“Yes, but the main tail, that most people see, points away.”

I can clearly recall seeing both tails of Hale-Bopp, and I also recall that the yellow/white dust tail was the most prominent of the two.

Are you saying this is atypical?
albertd
08-03-2013
Originally Posted by njp:
“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?”

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.
njp
08-03-2013
Originally Posted by albertd:
“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.”

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.
albertd
08-03-2013
Originally Posted by njp:
“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.”

That is all very interesting, but nothing whatsoever to do with Joe-Public's non-scientific view of things, as was my point about the BBC's graphic (which I see has now been corrected).
Elissa Richards
08-03-2013
Guys you'll argue each other into the ground on this....let it go!!
albertd
08-03-2013
Originally Posted by Elissa Richards:
“Guys you'll argue each other into the ground on this....let it go!!”

Yes, very happy to!
Elissa Richards
08-03-2013
Is anyone going to attempt to image it? Be interesting to see the DS'ers can do!
fender101
08-03-2013
Originally Posted by albertd:
“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.”

"Bright comet 'lighting sky' as it flies by Earth".

Have they seen the weather forecast for the next four days? This comet will have to be ****ing bright.
BeethovensPiano
08-03-2013
Maybe some big news coming from the Curiosity rover next week?

http://spaceref.com/mars/curiousmars...-analysis.html
Tissy
11-03-2013
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
Milian
11-03-2013
*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/
Pootmatoot
11-03-2013
Originally Posted by Milian:
“*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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