Asteroid Data URL

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Re: Asteroid Data URL

by han.k » 07 Feb 2018, 13:03

I found the solution. I was using the next calculated perihelion of August 2019 rather then the past perihelion of December 2017. Due to the highly elliptical orbit this resulted in big rounding errors. In version 4.0.0 RC7a I will calculate the nearest perihelion and then the result is spot on.

Re: Asteroid Data URL

by han.k » 07 Feb 2018, 10:47

Good news.

Maybe If current year fails I should check for previous year to make it more failure proof.

I discovered a new problem last night. I have imported the asteroid date of a NEO, asteroid 276033 (2002 AJ129) from https://ssd.jpl.nasa.gov/horizons.cgi

The correct orbital elements are:
276033 (2002 AJ129) |2018 02 06.000 |0.914920 |1.370739|15.455360|138.042099|211.008487|2000 |23.392279 |18.7 |0.150

However the position is calculated wrong. This is strange. The position calculation of asteroids have been tested a hundreds of times and the program never failed me but for this one the program makes a mistake. A HNSKY of 10 years ago does the same, this is an oddity.

I typed in the orbital elements in comet style and luckily this gives the correct position:

276033 (2002 AJ129) |2000|20171229.90682|0.11662233 |0.914920 |211.008487 |138.042099 | 15.4553597 |18.7 |0 | 276033

HNSKY uses one routine for both asteroids/comets. The routine input is comet orbital elements so there is something wrong with the conversion from asteroid to comet orbital elements.

I will work on a solution.

Re: Asteroid Data URL

by Tekkie » 07 Feb 2018, 04:35

Follow-up: The minor planet center has updated its data, and the 2018 link works now.

Re: Asteroid Data URL

by Tekkie » 18 Jan 2018, 01:30

Thanks for the info. The asteroid data isn't of critical importance to my regular observing, so I'll wait for the update to come out in due course.

Re: Asteroid Data URL

by han.k » 17 Jan 2018, 10:56

The minor planet center updates the asteroids only a few times a year. The 2018 update will come.

You could update the 2017 database using the numerical integration routine in the program. Just select all asteroid and select numerical integration and save the result. It will be highly accurate. No need to wait for minor planet center.

You can also download from the minor planet center huge main asteroid database, open it in a word processor or browser and select the first 1000 asteroids and save them as text file. Then just open the file in the editor and they will be converted.

But I would not worry too much about the 2018 update. The 2017 will be fine.

Asteroid Data URL

by Tekkie » 17 Jan 2018, 01:04

Thanks for the fantastic program. The URL to update the asteroid database seems to be failing as of 2018. The file it is looking for doesn't exist when 2018 is used in the path, though is still works if manually edited back to 2017 (but maybe less accurate). Is there a better location to find current asteroid data in the correct format?

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