At night, bright enough to keep out of central Harrow (6)
I believe the answer is:
starry
'at night bright enough' is the definition.
I know that 'night' relates to this answer.
'keep out of central harrow' is the wordplay.
'keep' becomes 'stay' (I've seen this in another clue).
'out of' means one lot of letters goes inside another (some letters on the outside of others).
'central' indicates the central letters.
The centre of 'harrow' is 'rr'.
'stay' going around 'rr' is 'STARRY'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for starry that I've seen before include "Astral" , "with many famous actors" , "Of celebrities" , "Description of Orion" , "(Of the night sky) sparkling" .)