Off the charts

 Guess you could say this puzzle's solution was written in the stars...

Happy December — can't believe this will be the last puzzle of the semester for me! I've really enjoyed messing with different kinds of ideas and tools these last couple months, and I'm very excited for whatever puzzling holds in 2022. (For anyone observing, since I just missed it, happy palindrome/ambigram day too, yesterday!  ~ 12022021 ~ )

This puzzle is dedicated to my friends who steadfastly refuse to keep me from making a day without hearing about this particular topic (xoxo love y'all!). If we don't talk before then, best wishes for restful and healthful time with friends and family at the end of this year, and I'll catch you soon!