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Quick asteroid ephemeris calculated with Python, to prepare photometric observations

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When preparing observations of asteroid lightcurves, one problem I had to face in the past months was to identify the appropriate targets. It is not easy to find out which asteroids are visible in a given right ascension and declination range, with bright enough magnitude and non-singular rotation period. So far I was using the MPC checker service to find which bright asteroids are in which sky areas, and then I had to check their rotation periods afterwards. I could not find a better way using the MPC website.

To help for this task, I recently wrote two small Python scripts. The first one connects automatically to the Telnet server of JPL horizons service, and downloads all available information for the 20000 first asteroids (including orbital elements, magnitude parameters, size in km, color, rotation period, etc). Then the second one computes, for a given date, the positions and magnitudes. The outputs of both scripts are saved in text files.
1- the first script, that downloads asteroid information, is here
2- the second script, that computes the positions, is here

The positions are not extremely accurate, they are calculated at the mean equinox of the ephemeris date, while the osculating orbital elements are given for a different date. In addition, I do not calculate time shift due to light propagation. But unless the target is a NEO, accuracy should be better than 1 arc min.
3- the output text file containing all the orbital elements is here
4- finally the positions of all asteroids having magnitude < 15 on 12 June 2011 are given here

Asteroids brighter than magnitude 16

I started to plot the positions of the asteroids with magnitude smaller than 16. The plot that I obtained is depicted here, with the Sun position indicated with a large yellow disk. It is interesting to see that the spread in declination is much larger at the opposite direction of the Sun. This effect comes from the lower distance between Earth and the asteroid main belt.



Asteroids brighter than magnitude 15

Now focusing to the asteroids observable in good conditions, I obtained the following plot.



The brightest asteroids are these ones:



All asteroids brighter than magnitude 15, at positive declination and more than 90 degrees from the Sun are given in the table below:



From my garden, it is not possible to observe for more than 1-2 hours at declinations lower than 10 degrees. The only well placed target are thus:
- 856 Backlunda (with a very difficult period close to 12 hours, and too much to the West to be observable comfortably for a few months)
- 357 Ninina (with a very long period)
- 1069 Planckia (already observed)
- 226 Weringia (why not ?, but long period)
- 273 Atropos (very difficult period)
- 1051 Merope (long period)
- 2 Pallas (no interest since the asteroid is well known)
- 1036 Ganymed (yes !)
- 631 Phillippina (yes !)