What are Nicolaus Copernicus Main science findings?

He found an old magnet in a heap of scrap metal and some broken test tubes in amongst some trash.

Copernicus elucidated the Sun centered Solar system, which inspired Johannes Kepler to formulate his laws of planetary motion, which in turn inspired Isaac Newton to invent the mathematics of Calculus, as well as Newton's laws of motion and Universal Gravitation. "If I have succeeded in life it is because I have stood on the shoulders of giants."--Sir Isaac Newton. Copernicus was one of those giants. 

Let me Google that for you.

The quantity theory of money and Gresham's law, if economics counts as a science.

None, since he was a church official in a century when most scientists were frowned on if not persecuted.  Nicky waited until after he was dead to publish his work on the solar system that went against the Bible and church teachings.

I dispute Retief's answer.  He sends you three links.  I selected at random the link to space.com.  It does NOT provide "other" findings than the heliocentric model, although it argues that the heliocentric model had the larger implication that the universe would look much the same from anywhere in the solar system.  Swell, the heliocentric model has many implications, and Copernicus' ability to explain away the "epicycles" needed by the geocentrists was quite a mathematical feat, and relied on his many accurate observations of planetary positions.  But did Copernicus contribute other major findings to science, that are "outside" of his development of a heliocentric system?  

The second-best known achievement of Copernicus may be his enunciation of a monetary principle that came to be called "Gresham's Law," but which Copernicus asserted earlier than Gresham did.  Currency of low value drives out currency of high value, because everyone hoards the high-value currency.  

I guess taking a few seconds to search online for yourself was too hard.

https://www.enotes.com/homework-help/w-did-nicolau...

https://www.space.com/15684-nicolaus-copernicus.ht...

https://www.britannica.com/biography/Nicolaus-Cope...