dt is not the derivative, it is the delta t, difference in time, time shift formula. The notation for the derivative is d/dt (dt is the differential notation).

The ether drift is latitude dependent.

http://www.orgonelab.org/miller.htmThe Coriolis effect is SUBLUMINAL.

The Sagnac effect is SUPERLUMINAL.

That is, if you want the Sagnac effect, the formula must reflect the superluminal velocity. No superluminal velocity, no Sagnac formula.

Coriolis and Sagnac effect formulas for a square ring laser interferometer:

https://www.theflatearthsociety.org/forum/index.php?topic=30499.msg2153966#msg2153966Derivation of the Sagnac effect formula:

https://www.theflatearthsociety.org/forum/index.php?topic=30499.msg2117351#msg2117351KASSNER EFFECT

https://www.theflatearthsociety.org/forum/index.php?topic=30499.msg2234871#msg2234871 (part I)

https://www.theflatearthsociety.org/forum/index.php?topic=30499.msg2235136#msg2235136 (part II)

Dr. Gianfranco Spavieri

In both the outward and return paths, the one-way speed is c (in agreement with Einstein’s second postulate) if the length L of the outward path covered by the signal is reduced to L(1 - 2v/c) < L in Eq. (3).

CORIOLIS EFFECT = a path measuring L(1 - 2v/c), a comparison of two separate/different segments

SAGNAC EFFECT = a path measuring L, a comparison of two continuous loops

Therefore, Michelson and Gale, Silberstein, Langevin, Post, Bilger, Anderson, Steadman, Rizzi, Targaglia, Ruggiero, have been measuring ONLY the CORIOLIS EFFECT formula (area and angular velocity), nothing else. The formulas features on the wikipedia and mathpages websites are the CORIOLIS EFFECT equations, not the correct SAGNAC EFFECT formulas.

Here is the crown jewel of all the SAGNAC EFFECT formulas:

**Δt = (l**_{1} + l_{2})/(c - v_{1} - v_{2}) - (l_{1} + l_{2})/(c + v_{1} + v_{2})The velocity terms are immediately identified:

c - v_{1} - v_{2} and

c + v_{1} + v_{2}.

**Δt = (l**_{1} + l_{2})/(c - v_{1} - v_{2}) - (l_{1} + l_{2})/(c + v_{1} + v_{2}) = 2[(l_{1}v_{1} + l_{2}v_{2})]/c^{2}