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asteroid 2012 DA14 next week



 
 
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  #1  
Old February 7th 13, 09:09 AM posted to uk.sci.astronomy
N_Cook
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Posts: 86
Default asteroid 2012 DA14 next week

If I go out on Valentine's day next week with binoculars and clear sky at
the Plough and manage to see this object going zenithwards across the handle
of the pan-handle 21:00 to 22:00 or so, will it be varying brightness from
tumbling. ?
If it is tumbling before near earth encounter would that gravitational
encounter stop the the tumbling of an asymetric object?


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  #2  
Old February 7th 13, 08:15 PM posted to uk.sci.astronomy
Sjouke Burry[_3_]
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Posts: 24
Default asteroid 2012 DA14 next week

"N_Cook" wrote in :

If I go out on Valentine's day next week with binoculars and clear sky
at the Plough and manage to see this object going zenithwards across
the handle of the pan-handle 21:00 to 22:00 or so, will it be varying
brightness from tumbling. ?
If it is tumbling before near earth encounter would that
gravitational encounter stop the the tumbling of an asymetric object?




Yes.
No.
  #3  
Old February 8th 13, 09:20 AM posted to uk.sci.astronomy
N_Cook
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Posts: 86
Default asteroid 2012 DA14 next week

Sjouke Burry [email protected] wrote in message
2.10...
"N_Cook" wrote in :

If I go out on Valentine's day next week with binoculars and clear sky
at the Plough and manage to see this object going zenithwards across
the handle of the pan-handle 21:00 to 22:00 or so, will it be varying
brightness from tumbling. ?
If it is tumbling before near earth encounter would that
gravitational encounter stop the the tumbling of an asymetric object?




Yes.
No.


Would the brightness variability be perceivable by simple looking through
binoculars (if seen at all) and over what sort of periodicity?


  #4  
Old February 8th 13, 12:13 PM posted to uk.sci.astronomy
N_Cook
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Posts: 86
Default asteroid 2012 DA14 next week

For the UK it is the 15 Feb


  #5  
Old February 8th 13, 07:20 PM posted to uk.sci.astronomy
Sjouke Burry[_3_]
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Posts: 24
Default asteroid 2012 DA14 next week

"N_Cook" wrote in :

Sjouke Burry [email protected] wrote in message
2.10...
"N_Cook" wrote in :

If I go out on Valentine's day next week with binoculars and clear

sky
at the Plough and manage to see this object going zenithwards across
the handle of the pan-handle 21:00 to 22:00 or so, will it be

varying
brightness from tumbling. ?
If it is tumbling before near earth encounter would that
gravitational encounter stop the the tumbling of an asymetric

object?




Yes.
No.


Would the brightness variability be perceivable by simple looking

through
binoculars (if seen at all) and over what sort of periodicity?



Depends on how fast it is tumbling, and how irregular the surface is.
  #6  
Old February 12th 13, 10:42 PM posted to uk.sci.astronomy
Dr J R Stockton[_193_]
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Posts: 40
Default asteroid 2012 DA14 next week

In uk.sci.astronomy message
..12.10, Thu, 7 Feb 2013 20:15:55, Sjouke Burry posted:

"N_Cook" wrote in :

If I go out on Valentine's day next week with binoculars and clear sky
at the Plough and manage to see this object going zenithwards across
the handle of the pan-handle 21:00 to 22:00 or so, will it be varying
brightness from tumbling. ?
If it is tumbling before near earth encounter would that
gravitational encounter stop the the tumbling of an asymetric object?




Yes.
No.



I would expect that a non-tumbling asymmetric asteroid approaching from
infinity would be tumbling after the encounter. Gravitational motion is
time-reversal symmetric. Therefore an asteroid approaching from
infinity with just the right tumble would not be tumbling when it
finally reached infinity again. So only rather probably No.

IIRC : Consider not Niven's "Neutron Star" itself, but comments made
after its publication, such as in
http://en.wikipedia.org/wiki/Neutron_Star_%28short_story%29#Notes blob
2.

--
(c) John Stockton, nr London, UK. Mail via homepage. Turnpike v6.05 MIME.
Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.
  #7  
Old February 13th 13, 10:11 AM posted to uk.sci.astronomy
N_Cook
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Posts: 86
Default asteroid 2012 DA14 next week

Dr J R Stockton wrote in message
nvalid...
In uk.sci.astronomy message
.12.10, Thu, 7 Feb 2013 20:15:55, Sjouke Burry posted:

"N_Cook" wrote in :

If I go out on Valentine's day next week with binoculars and clear sky
at the Plough and manage to see this object going zenithwards across
the handle of the pan-handle 21:00 to 22:00 or so, will it be varying
brightness from tumbling. ?
If it is tumbling before near earth encounter would that
gravitational encounter stop the the tumbling of an asymetric object?




Yes.
No.



I would expect that a non-tumbling asymmetric asteroid approaching from
infinity would be tumbling after the encounter. Gravitational motion is
time-reversal symmetric. Therefore an asteroid approaching from
infinity with just the right tumble would not be tumbling when it
finally reached infinity again. So only rather probably No.

IIRC : Consider not Niven's "Neutron Star" itself, but comments made
after its publication, such as in
http://en.wikipedia.org/wiki/Neutron_Star_%28short_story%29#Notes blob
2.

--
(c) John Stockton, nr London, UK. Mail via homepage. Turnpike v6.05

MIME.
Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and

links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm,

etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail

News.


I'll try looking ESE about 20:00, when brightest, but whether I can make out
Denebola is another matter, I hope these path charts are still valid
http://www.britastro.org/~rmiles/Ima...950-2100UT.png
Path 20:00 to 21:00

http://www.britastro.org/~rmiles/Ima...100-0100UT.png
Path 21:00 to 01:00


  #8  
Old February 16th 13, 10:58 AM posted to uk.sci.astronomy
N_Cook
external usenet poster
 
Posts: 86
Default asteroid 2012 DA14 next week

Too much mist at horizon level for me to see with binos at the Leo level ,
and returned to it for the Plough crossing but had clouded over by then, so
did not see it.
I wonder what traumatised state that Russian was who took that image of that
meteor/ite coming straight for him, an amazing piece of phone-cam imagery


 




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