IV.1. Basic concepts

The present part of the package enables the differences of observed and computed positions of minor planets to be found in various coordinate systems (equatorial, ecliptic, horizontal). Some part of computed values of O – C (observed position minus computed one) can be separated from all others depending on the limitations imposed on their value and/ or observatory.

There is an opportunity to perform O-C calculations for objects which are absent in the data base of the package. Such objects can be described by orbital elements or by initial coordinates and velocities. In each case there are two possibilities:

• calculations should be performed for single object;
  
  
• calculations should be performed for a list of objects.

In case of a single object user should introduce corresponding data into positions shown at the screen. There is possibility to use different systems of elements, such as M,n or M,a or T,q. Some of data, such as designation of the object, H, G can be omitted. If H, G are not introduced the visual magnitude of the object is not computed.

In case of numerous objects user should introduced the name of the file with elements or coordinates and velocities of objects. On pressing Browse button one can find the wanted file in memory and open it. On pressing Edit file button user has a possibility to look through the list of object elements or their coordinates and velocities to add or to change it.

The set of orbital parameters and their order of following can differ from that considered as standard. For example, the designations of objects in the list can occupy the last position in each line. AMPLE gives opportunity to use such list not changing it. After selection of List of orbits to the right side of the screen a field under the head line Order is appeared.

It contains the list of the orbital parameters in their succession as they were represented during the last run. If user wants to change the set of parameters of their following, he or she should press Modify button and then Clear button. Then at the left part of the screen one can mark those orbital parameters which are present in the list using that succession in which they are given in every line. For example, if the Epoch of the elements occupies the first position in every lines, the checkbox Epoch should be marked the first, and so on. In so doing, at the right of the screen under the head line Order the new orbital parameters in their new succession will be seen.

To start O – C calculation select Task item in menu bar and then select O – C item in drop-down menu.