First of all my apologies for not keeping up with the UK version of Daylight Saving Time. Hence I was off by an hour.
Thanks to all the participants for some excellent entries.
Now to my short list. I liked Buddy's economical #3 with change doing double duty, or perhaps the entire clue is an &lit. I think it works either way. Next up is Mattrom's educational #7. I also have Fieryjack's #10; I'm not usually a big fan of straight anagrams unless they have a nice surface as this one does. I also liked Mattrom @14. Mattrom gets the hat trick with her 18 also making the list. I always love a clue involving astronomy. Buddy's 24 is also a worthy contender. Rounding out my list is Patrich @ 26. Not only does he work in yours truly, but some mathematics as well.
It is just to much to resist; Patrick is the winner with:
Math prof’s change corrected sin to tan , I start to realise (10)
(My browser is flagging the misspelling of realize, but we'll ignore it. 😉)
I hope you enjoy your prizes:
How far does your mathematical knowledge go, Patrick? Perhaps you already know about the transition matrix?
https://www.youtube.com/watch?v=VeTjArt51Q4
If the transition matrix is not to your liking, maybe you are more interested in scene transitions in
The Matrix
https://www.youtube.com/watch?v=j3xe1XY7akg
As it turns out, the Wachowskis who wrote and directed the Matrix movies have both transitioned MTF. In fact, there is even a theory that the movies are an allegory about being transgender. If you're curious:
https://www.themarysue.com/decoding-the-transgender-matrix-the-matrix-as-a-transgender-coming-out-story/
Congratulations, Patrick.