hello, I would like to be able use wget for https page in console, how could I fix missing certificates?

my command is:
wget --user=*** --password=*** "https://***/***
Resolving isis.vse.cz... ***
Connecting to isis.vse.cz|***|:443... connected.
ERROR: cannot verify ***'s certificate, issued by `/C=NL/O=TERENA/CN=TERENA SSL CA':
  Unable to locally verify the issuer's authority.
To connect to isis.vse.cz insecurely, use `--no-check-certificate'.
Unable to establish SSL connection.
thank you in advance