A horizontal limit avoidance strategy for the equatorial telescope pointing process

Time-domain astronomy requires telescopes capable of rapid response and uninterrupted operation to observe light curves of transient astrophysical events in the shortest possible time. For equatorial telescopes, which are mainly used for meter-class telescopes, it is possible for the horizontal limit stop to interrupt the observation, especially during the pointing process as the telescope slews to the next object to observe. We discuss the procedures to estimate whether the horizontal limit stop will occur in the pointing process and propose an algorithm to prevent this. We consider several factors relating to the horizontal limit stop, including the latitude of the observation site, the current pointing of the telescope, the target pointing, the degree threshold of the horizontal limit stop, and the altitude threshold of the observable sky area for astronomy. Once factors are given, a set of discrimination procedures is conducted to determine whether the horizontal limit stop will be triggered in a single pointing process. If it is predicted to occur, then the telescope control software will alter the pointing course. Finally, we discuss some other related factors, such as RA and DEC axes having different pointing speeds, and observation sites in the Southern Hemisphere We demonstrate a method to keep equatorial astronomical telescopes away from the horizontal limit stop while in motion. This system can be beneficial if operating continuously for autonomous observations, to guarantee a rapid response for time-domain astronomy.