Astronomy is not withcraft and anyone who says that is ignorant, Christian or otherwise. However there is a risk in Eurocentrism which confuses astronomy and astrophysics with astrology. Astrology is Eurocentric numerology and since neither the Western number system, nor its calendar, nor its “zodiac” are original or Afrikan, so Afrikans or other indigenous peoples who use those things to guide their lives or those of others are deluded.
The spiritual or religious problem for christians and not just christians occurs when you elevate the worship of creation or the study of creation over the study of and obedience to God or to a level equal to that, which within the faith is spiritual adultery, crediting that which is subject to God and made by Him as independent of Him. Worshipping the motion and force of the stars and making them causal as opposed to the one who put them in motion, and determines their laws is contradictory. As much as one may venerate a tree, worship of it, not referencing its creator is a road to confusion. This is why early Christianity would see today’s Christmas trees, for example, as heresy.