Verified answer

I was a bit puzzled by your question because, as the top answerer in this category, I didn't know what "CT" was or what it meant in astronomy. So I googled it (which you could have done) and found that it usually refers to "connective tissue." I'd think you'd get a better answer faster if you asked in the correct category, perhaps "Medicine" or "Zoology." Even faster if you'd look it up in Google yourself.

You look at both, and note similarities and differences