Which app can check the relationship between duty day and day?

The method of keeping a diary in turn at twenty-eight nights is that one night represents one day, and twenty-eight nights represents twenty-eight, and so on. The 28th is a cycle, which happens to take turns around. So, according to the rhyme below, you can check whether the twenty-eight nights printed on the almanac are correct, just look at the day of the week on that star (the corresponding relationship will never change).