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orbital elements



 
 
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  #11  
Old February 24th 09, 02:22 PM posted to sci.astro.amateur
Quadibloc
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Posts: 7,018
Default orbital elements

On Feb 23, 7:07*pm, "U. N. McGregor" wrote:

How difficult is it to read this and understand it? *Is it written for
engineers and scientists etc.?
Remember , I am an amateur with limited math skills.


I don't think that determining orbital elements from observations is
described in too many places except in textbooks of celestial
mechanics, which, of course, are aimed at stretching the brains of
students rather than giving them pat cookbook formulae, and so this
sort of thing will usually be available in a form that requires a lot
of math to understand.

But I see some people on this thread have been able to provide helpful
answers.

  #12  
Old February 24th 09, 02:28 PM posted to sci.astro.amateur
Quadibloc
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Posts: 7,018
Default orbital elements

On Feb 23, 5:31*pm, Llanzlan Klazmon wrote:
On Feb 24, 1:03*pm, "U. N. McGregor" wrote:

Where can I find concise directions on how to determine orbital elements.
All I ever see on the internet is description about what they are and mean
but never the way to actually do that type of calculation.


http://www.projectpluto.com/find_orb.htm#gauss


Ah, I looked up and found that

http://www.projectpluto.com/find_orb.htm

is a page about software that does orbit determination. The page
doesn't itself explain the algorithm, but gives references to a
coupleof books.

John Savard
  #13  
Old February 24th 09, 02:36 PM posted to sci.astro.amateur
Quadibloc
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Posts: 7,018
Default orbital elements

On Feb 24, 2:04*am, Martin Brown
wrote:

If you want to do your own orbit determinations rather than derive the
equations from scratch then take a look at Project Plutos FindOrb.


And there's a link from there - didn't work, had to use Google - to
another program,

http://adams.dm.unipi.it/~orbmaint/orbfit/

of which source code in FORTRAN is available, so the mysteries of
orbit determination can be plumbed that way.

John Savard
  #14  
Old February 24th 09, 04:24 PM posted to sci.astro.amateur
Chris L Peterson
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Posts: 10,007
Default orbital elements

On Tue, 24 Feb 2009 00:03:41 GMT, "U. N. McGregor"
wrote:

Where can I find concise directions on how to determine orbital elements.
All I ever see on the internet is description about what they are and mean
but never the way to actually do that type of calculation.


I've found _Methods of Orbit Determination for the Micro Computer_, by
Dan Boulet, to be the best _practical_ book on orbital dynamics (by
far). It briefly covers history and derivations, but is strongly focused
on practical math and algorithms. It's available at
http://www.willbell.com/math/mc10.htm .
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
  #15  
Old February 24th 09, 07:02 PM posted to sci.astro.amateur
Golden California Girls
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Posts: 210
Default orbital elements

Chris L Peterson wrote:
On Tue, 24 Feb 2009 03:30:14 GMT, Golden California Girls
wrote:

It can't be calculated without calculus math skills.


I do orbital analysis all the time, and I never use calculus. You only
need that if you want to derive the equations. Just determining orbital
elements from observations requires nothing more than vector algebra.


It only requires search engine and data entry skills. Free software is out
there to do the computation, but it doesn't leave one with any understanding of
what is going on.
  #16  
Old February 24th 09, 08:32 PM posted to sci.astro.amateur
U. N. McGregor
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Posts: 8
Default orbital elements


Ok group thanks. As someone who wants to make observations of at least
NEO's , I understand that
carefully determining the changes in RA and DEC relative to known star
positions is the first step. What is the least
quality of CCD or CMOS digital camera is needed to take photos of orbits?
What is the best what is the best way
to determine good RA and DEC measures?



"Chris L Peterson" wrote in message
...
On Tue, 24 Feb 2009 00:03:41 GMT, "U. N. McGregor"
wrote:

Where can I find concise directions on how to determine orbital elements.
All I ever see on the internet is description about what they are and mean
but never the way to actually do that type of calculation.


I've found _Methods of Orbit Determination for the Micro Computer_, by
Dan Boulet, to be the best _practical_ book on orbital dynamics (by
far). It briefly covers history and derivations, but is strongly focused
on practical math and algorithms. It's available at
http://www.willbell.com/math/mc10.htm .
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com



  #17  
Old February 25th 09, 01:24 AM posted to sci.astro.amateur
Llanzlan Klazmon[_2_]
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Posts: 64
Default orbital elements

On Feb 25, 8:32*am, "U. N. McGregor" wrote:
Ok group thanks. *As someone who wants to make observations of at least
NEO's , I understand that
carefully determining the changes in RA and DEC relative to known star
positions is the first step. What is the least
quality of CCD or CMOS digital camera is needed to take photos of orbits?
What is the best what is the best way
to determine good RA and DEC measures?


I suppose by reference to star/stars in the same image of known RA and
DEC. You have to assume that the pros like the ESA Hipparchos team
have done their job properly.
  #18  
Old February 25th 09, 02:22 AM posted to sci.astro.amateur
Chris L Peterson
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Posts: 10,007
Default orbital elements

On Tue, 24 Feb 2009 19:32:09 GMT, "U. N. McGregor"
wrote:

Ok group thanks. As someone who wants to make observations of at least
NEO's , I understand that
carefully determining the changes in RA and DEC relative to known star
positions is the first step. What is the least
quality of CCD or CMOS digital camera is needed to take photos of orbits?


That's a difficult question to answer. It depends on the brightness of
the NEOs you expect to detect, and on the degree of accuracy you want to
achieve. With an ordinary DSLR you can certainly do some acceptable
work, even though you are limited by camera noise and the color sensor.
If you want to do really accurate work, however, you want a cooled, B&W
CCD camera specifically designed for long exposure astroimaging.

What is the best what is the best way
to determine good RA and DEC measures?


You need to use plate solving software. This analyzes an image,
determines the positions of all the stars and compares them to catalog
positions. You can readily get sub-arcsecond positions for asteroids
this way. I use a program called Pinpoint. There is also software built
into TheSky/CCDSoft, as well as several programs that are cheap or free.
It is important to pick your reference catalogs carefully if you want
the best results- there is a balance between the depth of the catalog
(more stars is good), and the accuracy of the stellar positions (some
rich catalogs are not very accurate).
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
  #19  
Old February 25th 09, 04:58 AM posted to sci.astro.amateur
William Hamblen[_2_]
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Posts: 236
Default orbital elements

On Tue, 24 Feb 2009 19:32:09 GMT, "U. N. McGregor"
wrote:

Ok group thanks. As someone who wants to make observations of at least
NEO's , I understand that
carefully determining the changes in RA and DEC relative to known star
positions is the first step. What is the least
quality of CCD or CMOS digital camera is needed to take photos of orbits?
What is the best what is the best way
to determine good RA and DEC measures?


You want to get a telescope and imager that has a large enough field
to have sufficient reference stars. A monochrome detector also is
better than a one-shot color camera. The Handbook of Astronomical
Image Processing from Willmann-Bell also includes AIP4WIN software,
which does astrometry (finding positions from images). It is a decent
book with practical information. University textbooks on spherical
astronomy will have the heavy duty math.

Bud
  #20  
Old February 25th 09, 01:03 PM posted to sci.astro.amateur
oriel36[_2_]
external usenet poster
 
Posts: 8,478
Default orbital elements

On Feb 24, 7:32*pm, "U. N. McGregor" wrote:
Ok group thanks. *As someone who wants to make observations of at least
NEO's , I understand that
carefully determining the changes in RA and DEC relative to known star
positions is the first step. What is the least
quality of CCD or CMOS digital camera is needed to take photos of orbits?
What is the best what is the best way
to determine good RA and DEC measures?


Ra/Dec effectively ignores the Earth's orbital elements and runs
everything off axial coordinates,the worse part is that it does so
within the equable 365/366 day calendar system.

If you are an astrophotgrapher who is snap happy working off the
astrologiccal Ra/Dec system then it is a great convenience as as the
forground objects such as the moon,planets,comets are pasted on to the
celestial background like ornaments on a rotating christmas tree.

The original astronomers,both geocentric and
heliocentric,distinguished the motions of the planets AGAINST the
stellar background whereas empiricists beginning with Newton, was
working off Flamsteed's newly invented Equatorial Coordinate System
and its 'predictive' positional nature based on the motion of the
planets WITH the stellar background.

The empirical 'predictions' therefore contain the original
astrological framework that Flamsteed introduced to the daily rotation
and orbital motion of the Earth.Wasnt to see what it looks like -

http://www.youtube.com/watch?v=XTTDWhky9HY

If you want orbital elements then start with the Earth and the
specific way it orbits the Sun otherwise you will be nothing more than
an astrologer with a magnification habit rather than an astronomer.










"Chris L Peterson" wrote in messagenews:r248q45fqrjph7lcne1evkqae3d2uhgi6u@4ax .com...



On Tue, 24 Feb 2009 00:03:41 GMT, "U. N. McGregor"
wrote:


Where can I find concise directions on how to determine orbital elements.
All I ever see on the internet is description about what they are and mean
but never the way to actually do that type of calculation.


I've found _Methods of Orbit Determination for the Micro Computer_, by
Dan Boulet, to be the best _practical_ book on orbital dynamics (by
far). It briefly covers history and derivations, but is strongly focused
on practical math and algorithms. It's available at
http://www.willbell.com/math/mc10.htm.
_________________________________________________


Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com- Hide quoted text -


- Show quoted text -


 




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