[tacticalogic]

I'm going to think about this a little more before I start taking sides.

I'm not convinced yet that the difference in observed and actual position is due to aberration, and that light-time doesn't enter into it.

Aberration is the result of moving perpendicular to the light source. That should mean that at sunrise and sunset aberration is effectively zero. At sunset, when the center of the sun is exactly on the horizon, there should be no difference in observed position due to aberration, but that light left the sun 8.3 minutes ago. The rotational velocity is constant, so when you're seeing that, the actual physical center of the sun should be about 2 degrees below the horizon from where you are.

[Ethan Clive Osgoode]

At sunset, when the center of the sun is exactly on the horizon... that light left the sun 8.3 minutes ago. The rotational velocity is constant, so when you're seeing that, the actual physical center of the sun should be about 2 degrees below the horizon from where you are.

So where would the actual physical Sirius be, when its observed position is likewise on the horizon? That light left Sirius 8.6 years ago.

[grey_whiskers]

Even the greatest get puzzled over simple things which are easily misunderstood until you understand them.

Go read the episode in Surely You're Joking, Mr. Feynman, about his attempt while a young prof at Cornell to set up an experiment on what would happen if you put a rotating sprinkler underwater and then turned it on.

Full Disclosure: It may have been in What Do You Care What Other People Think. I'm not sure ;-)

Cheers!

[Fichori]

“Aberration is the result of moving perpendicular to the light source. That should mean that at sunrise and sunset aberration is effectively zero.” [excerpt]

Tip,

the Earth, in its yearlong orbit around the Sun, is constantly moving perpendicular to the incoming light from the Sun at ~30,000 meters/second, causing around 0.00573° of displacement due to Annular aberration.
This is nearly constant.

The transverse speed contributed by the rotation of the Earth has a maximum of ~463.8 meters/second at high noon on the equator.

So at sunrise, you get ~30,000m/s transverse velocity, and at high noon you get ~30,463m/s transverse velocity.

Or, ~0.00573° at sunrise and ~0.00582° at noon.