(You can only go to the “the hard is what makes it great” well only so many times.)
Yes, you have to learn lots of math, physics, programming, and many other related things in order to tackle new and interesting research questions in astronomy. The same is true for many fields. But at the end of the day? We are all banging our heads against walls over a minus sign, or a factor of 2, or mixing up log-10 with natural log, or losing track of which star is which. This kind of “stupid mistake” hurdle is what really makes research hard.
The sheer volume of little details makes it inevitable that at least one will be wrong the first time through any problem, whether theoretical or experimental.
Also note the whole “we first tested this on data where we know the answer” bit. Good protocol.