In this first section, we will learn how to download asteroid observations from the ALCDEF database, using the TRAPPIST observations of 10 Hygiea as an example.

  1. Open your Internet browser and navigate to the ALCDEF Database main page at In there, you will notice the section Statistics and Search. Click the Search Database button.

  2. This opens a new page with one section, called Asteroid Search. It allows you to enter the name of the asteroid, for which you want to retrieve ALCDEF observations, in the Search for field. We enter Hygiea and press the Submit button.

  3. A new section appears on this page, called ALCDEF Search Results. It tells you that 18 light curves of 10 Hygiea exist in the database, and that the first one was obtained on 2018-09-11 and the last one on 2019-12-06. Click the Display button.

  4. This opens a new page with a section called ALCDEF Lightcurves for (10) Hygiea. It shows a table with a series of check boxes in the Save column. We are interested in the TRAPPIST observations of 10 Hygiea and as mentioned in the introduction, these were obtained between 2018, Sep 11th and 2018, Oct 18th. Hence, we deselect the Save entries at the bottom, containing more recent observations of this asteroid. When done, press the Download button.

  5. The result of this will be a text file, stored in the Downloads folder of your PC, containing all requested observations of 10 Hygiea in ALCDEF format.