Every telescope needs a horizon table, which tells where the telescope can look in the sky, and also from which parts of the sky the Moon can shine on the objective. Without a horizon table, the programs will assume that the telescope has an unobstructed view of the horizon --- an assumption that is probably wrong. The name of the table is keyed to the name of the telescope; see the Appendix.
If you need to make up a new table, the command MAKE/HORFORM will provide you with a form to fill in while gathering the data, which can then be entered into the empty table provided.