orbital calculations

[pepperstone]

Hey, does anyone know if there is already a forum here about calculation orbitals from visual observations? I wouldn't mind giving it a go. I googled it and nothing useful came up either. Perhaps someone else knows a good place to start?

Thanks

[jungle11]

There's a sight I saw when reading about orbits in Astronomy 101 called Orbit-On-Web, Where it tells you how to approximate an orbit using positions taken at different times. I haven't really looked at it but sounds like it might help you.

cheers

[Coen]

Made assumption that you are thinking solar system objects as compared to say Earth orbiting or binary stars.

Did find: http://www.ara.roma.it/MACE/Baer/CODES.pdf which has links to code. Have not used so can not say much about it personally.

There is also: http://www.projectpluto.com/find_orb.htm

A trip to the library for some celestial mechanics books - there are some good ones with Year 12 to 1st Year uni maths that should cover things - you get to like matrices.

There are also some old(?) books which have computer code for calculating orbits etc. Astronomy with a micro computer and other such title types should narrow the search.

[pepperstone]

Hey,

Thanks, and yes I was talking about solar system objects- I should have been more specific.

I'll look into it.

Thanks again.

[Wavytone]

Boldy looking at a difficult path. Hope your calculus is good.

Are you looking for a least-squares fit to some observations in the past, or want to do a rough fit for an object that can be refined using successive approximations (from more observations) ? The first is the Gauss method, the second is Lamberts method, applied for newly discovered objects. The Lambert method also is used if you have simultaneous observations from more than 1 place (eg metors) or NEO's.

You'll need to master the maths in "Orbital Motion" by AE Roy.

Spherical trigonometry is a pre-requisite - the classic text is "Spherical Trigonometry" by W.M. Smart.

Here's a pseudocode for the Gauss method:
http://www.physicsforums.com/showthread.php?t=36657

Lamberts method is described in this paper from the AJ:
http://www.iop.org/EJ/article/1538-3881/127/4/2424/203453.web.pdf?request-id=50e11fbe-6e75-4934-bed8-2fc3e1e7422e


There's also a method due to Gibbs:
http://en.wikibooks.org/wiki/Astrodynamics/Orbit_Determination#Gibbsian_Method

Isaac Newton worked out a prediction for Halleys comet - without a computer, slide rule or trig tables. A fairly staggering achievement when you understand the computational accuracy required.

[Coen]

Notes from someone's school project (determining orbit of Hale Bopp from their own observations): http://wsx.lanl.gov/WebPub/scifair_comet.pdf

Ricci's astronomy software might have something: http://www.pierpaoloricci.it/download/downloadsoftware_eng.htm

Some history: http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Orbits.html

History on Ceres orbit determination: http://american_almanac.tripod.com/ceres.htm

An astronomical almanac is needed if you are looking for the book-angle i.e. library, as you need to know where the Sun is fairly accurately. You can either work it out or look it up.

Enjoy.

[pepperstone]

Brilliant! Those sources are just what I'm after. I know my mathematics very well, but there's obivously a lot more to consider.

Thanks everyone. I think I'll have to get reading.

[bojan]

This was discussed here on this forum.. I posted BASIC programme that does this task..
Have a look here:
http://www.iceinspace.com.au/forum/showthread.php?t=37651&highlight=bojan+orbit