The format for the database is xml but the Windows ExploreStars version of the dataset is going to change when the Windows version of the ExploreStars is updated and compiled under the Windows Universal Platform. I think the Android has the new structure currently and the iOS version which will be released soon also has the same structure. I will contact Dan to find out what his plan are currently for sharing that information.
This structure only applies to the stellar and other "fixed" objects in the sky (nebulae, clusters, galaxies, etc). The solar system objects are fixed currently in the ExploreStars dataset and are built into the programs Ephemeris routine that I wrote. We would need to build a user interface to store and use user defined solar system objects into the program. It's possible, but this is the first time we have had a request for it. Typically if you are going to image these objects, you would use the ASCOM connection with your own third party program such as Cartes du Ciel, Astrometrica, or other programs that allow you to download the MPO minor planet dataset. This is what I do when doing my minor planet or comet imaging. I will talk to our developer about this and see how much work it would be.
FYI - When I wrote the ephemeris code, I used this reference to create it.
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