Most non-rationalists, when confronted with the Gemara about the sun's path at night, immediately respond by citing Rabbeinu Tam's view that the Sages of Israel were actually correct. Over at Divrei Chaim, I have been pointing out that the overwhelming majority of Rishonim, as well as a number of significant Acharonim, accept the Gemara at face value, that the Sages of Israel were mistaken. To his credit, R' Chaim does not quibble with this, or suppress me from stating it, or claim that it is forbidden to subscribe to such a view. However, he does suggest that one should follow the consensus of the Torah world which is to follow the opposing view.
I have two related observations to make about this.
First of all, R' Chaim's approach is very much atypical. The standard approach in the non-rationalist camp is to deny that historically there was a strong rationalist approach and that most Rishonim explained this Gemara k'pshuto.
Second, I think that his idea, that today's Torah authorities can reject the consensus of the overwhelming majority of Rishonim, would come as a shock to many people in that world. They have the idea that they are continuing what was the normative approach to Judaism throughout the ages. In fact I think that it is partly due to this that many people will deny that the majority of Rishonim said that Chazal erred scientifically. They would not be comfortable with the idea that they are going against most Rishonim.
The question is, what does the word "mesorah" mean, and what do people think it means? I think that most people think that it means "the normative approach to Judaism throughout the ages" - the "tradition" i.e. that which has been traditionally, historically, held. But what many people are actually using it to mean is "hachra'ah" - the decision of recent and contemporary authorities as to what is acceptable. Thus it can happen that an innovation, rather than a tradition, can be termed "the mesorah."