Many selective colleges think of high school astronomy, zoology and psychology as “lite science” and do not prefer them over one year of physics, one year of chemistry, and one year of biology, and an additional year of one of those subjects at an advanced level. That’s true even if you take astronomy, zoology or psychology at the AP level.
For example: Harvard doesn’t give AP course credit unless a student chooses “Advanced Standing” (the exception is the AP Foreign Language course), but look at Yale’s AP credit list. Astronomy is not listed, while no credits are given for Psychology: http://catalog.yale.edu/freshman-handbook/academic-information/acceleration/table-of-acceleration-credit/. It’s the same over at Princeton: https://www.princeton.edu/pub/ap/table/ and Stanford: https://registrar.stanford.edu/students/transfer-credit-and-advanced-placement/advanced-placement/ap-credit-chart and MIT: http://web.mit.edu/firstyear/prospective/credit/ap.html
My recommendation: Don’t take astronomy instead of regular physics. I’m sure you have room in your schedule, but you are personally preferring to take courses you might enjoy, rather than those that selective colleges expect to see on a student’s transcript.