Apex domains cannot have CNAME records.
Question and response
Question
dig nova53.org. NS
Answer
nova53.org. 5 NS ORION.NS.NOVA53.NET.
nova53.org. 5 NS CYGNUS.NS.nova53.org.
nova53.org. 5 NS PERSEUS.NS.NOVA53.COM.
nova53.org. 5 NS DRACO.NS.NOVA53.NET.
Authority
The response has no authority records.
Additional
cygnus.ns.nova53.org. 3 A 193.30.32.32
perseus.ns.nova53.com. 3 A 193.30.33.33
cygnus.ns.nova53.org. 3 AAAA 2a0c:8540:3:0:0:0:0:5353
perseus.ns.nova53.com. 3 AAAA 2a0c:8540:4:0:0:0:0:5353
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0