Crescent look modern on satellite (3,4)
I believe the answer is:
new moon
'crescent' is the definition.
(I've seen this before)
'modern on satellite' is the wordplay.
'modern' becomes 'new' (associated in meaning).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'satellite' becomes 'moon' (moon is a kind of satellite).
'new'+'moon'='NEW MOON'
'look' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for new moon that I've seen before include "Lunar narrow, waxing crescent" , "Beginning of first quarter" , "Satellites phase" , "Phase of Earth's satellite" , "First appearance of a waxing satellite" .)