By rights they are times, we find it "easier" to work/think in degrees, however I suspect it is wrong.
Which then raises the problem that 1 day, as in one 360 degree rotation of the earth, is 23 hours and 56 minutes long not 24 hours.
23 hours 56 minutes is the time the earth takes to complete one 360 degree rotation, 24 hours is the time it needs to rotates once and then about 1 degree more to place the sun back on your meridian.
One is termed Celestrial and the othe Solar, our clocks, watches etc work on Solar. Stars work on Celestrial. And that is where the problems start as both are termed "a day".
The difference in 1 "day", ~4 minutes, is why a star on your meridian at midnight is then on your meridian at midday 6 months later.
Will say a real pain to explain, and I haven't I suppose.
I get asked this a lot at outreach as the place has a "Clock" that shows the RA of an object/scope. So at say 20:30 at night a big illuminated clock is displaying 16:42 if aimed at M13 and the "time" isn't changing, whereas their watches are. At least 5 times a night I get it.
At the exact moment of the equinox, whereever you are you "look" along your specific meridian and record stars on it.
Your Meridian is on a given Longitude.
This Longitude is converted to the Celestrial time and that Time is the RA of the object.
Traditionally the Spring Equinox is used and the 2021 Spring equinox will be at March 20 at 09:37 UTC, not sure of the seconds but you can find it. The object position is "At the exact time" not on that day.
So Longitude is "easy" but not exactly right as something viewed from Greenwich at 1 degree Longitude, isn't in view 6 months later at 1 degree Longitude.