In alt.home.repair, on Wed, 11 Jul 2018 03:17:41 -0500,
wrote:

I have an antique porch light on my house that I like. So I dont want to
change the fixture. But I leave the light on all the time, so I can see
at night when I come home. Although I have a LED bulb in it, I'd still
like to have it shut off during the day.

It's a wall mounted light with a round base that fits against a box in
the wall. I can drill a hole in that base the size of a 1/2" knockout.
But do they sell low profile photrocells that can be put into such a
hole?

Wiring it should be easy. I am thinking there are 3 wires. One HOT, one
NEUTRAL on the INPUT side, and one HOT output to the light.

They sell or used to sell something that screwed into the socket and the
lightbulb screwed into it. A) it was almost an inch and might not fit
in your fixture. B) I wonder if the light would bounce back and make
the light go on and off. Maybe not.