What does the cryptic crossword clue "23 series on miracles, astonishing (5,5)" mean?

The wordplay uses an anagram. anagram of ON (synonym="ON") + MIRACLES (synonym="MIRACLES") = MINORSCALE The answer is MINORSCALE.

23 series on miracles, astonishing (5,5)

Guardian Cryptic #29152 | 13 Down | 2023-08-18 flower