Kepler's results are famous and widely used because they actually work.But they do not, that is why they were totally faked in the first place.
The acceleration of the rate of axial precession DEFIES Newtonian mechanics.
For you to complain of a single second, while at the same time you close your eyes and accept the totally faked treatise Nova Astronomia says a lot about you.
Let us examine the entire interval of 20 years using your figure of 2.6 seconds.

No leap seconds for 1988
For 1989 we add a single leap second: 0.5 (maximum value) + 1 = 1.5

One leap second for 1990: 0.6 (maximum value ) + 1 = 1.6

No leap seconds for 1991

One leap second for 1992: 0.5 (maximum value) + 1 = 1.5

One leap second for 1993: 0.8 (maximum value) + 1 = 1.8

One leap second for 1994: 1 (maximum value) + 1 = 2

Leap seconds for the years 1995, 1997, 1998
0.5 (maximum value) + 1 = 1.5

Leap seconds for the year 2005
0.5 (maximum value) + 1 = 1.5
Therefore the claims made by Uwe Homann are true: no precession for Sirius over a period of 20 years.
and cannot find any other, more reliable, evidence to back up your claim. If you do find any, please do present it for consideration. Really?
Let me demolish your false beliefs right now.
Here is the perfect test for our situation: Homann's claims and experimental data that Sirius does not undergo precessional motion vs. the claims made by the star catalogues you are so fond of.
Obviously, if the Earth does not orbit the Sun, then you are proven to be wrong.
The ORBITAL Sagnac effect is missing and is greater in magnitude than the ROTATIONAL Sagnac effect.
That is, the GPS satellites operate AS IF the Earth is not orbiting the Sun.
Moreover, the ORBITAL solar gravitational potential effect upon these satellites is also missing, is not being registered at all.
http://qem.ee.nthu.edu.tw/f1b.pdfThis is an IOP article.
The author recognizes the earth's orbital Sagnac is missing whereas the earth's rotational Sagnac is not.
He uses GPS and a link between Japan and the US to prove this.
In GPS the actual magnitude of the Sagnac correction
due to earth’s rotation depends on the positions of
satellites and receiver and a typical value is 30 m, as the
propagation time is about 0.1s and the linear speed due
to earth’s rotation is about 464 m/s at the equator. The
GPS provides an accuracy of about 10 m or better in positioning.
Thus the precision of GPS will be degraded significantly,
if the Sagnac correction due to earth’s rotation
is not taken into account. On the other hand, the orbital
motion of the earth around the sun has a linear speed of
about 30 km/s which is about 100 times that of earth’s
rotation. Thus the present high-precision GPS would be
entirely impossible if the omitted correction due to orbital
motion is really necessary.
In an intercontinental microwave link between Japan and
the USA via a geostationary satellite as relay, the influence
of earth’s rotation is also demonstrated in a high-precision
time comparison between the atomic clocks at two remote
ground stations.
In this transpacific-link experiment, a synchronization
error of as large as about 0.3 µs was observed unexpectedly.
Meanwhile, as in GPS, no effects of earth’s orbital motion
are reported in these links, although they would be
easier to observe if they are in existence. Thereby, it is evident
that the wave propagation in GPS or the intercontinental
microwave link depends on the earth’s rotation, but
is entirely independent of earth’s orbital motion around
the sun or whatever. As a consequence, the propagation
mechanism in GPS or intercontinental link can be viewed
as classical in conjunction with an ECI frame, rather than
the ECEF or any other frame, being selected as the unique
propagation frame. In other words, the wave in GPS or the
intercontinental microwave link can be viewed as propagating
via a classical medium stationary in a geocentric
inertial frame.
The author actually present a local-ether model (MLET, Modified Lorentz Ether Theory) in order to account for the MISSING ORBITAL SAGNAC EFFECT.
Published by the BULLETIN OF THE AMERICAN PHYSICAL SOCIETY, one of the most prestigious journals in the world today.
C.C. Su, "A Local-ether model of propagation of electromagnetic wave," in Bull. Am. Phys. Soc., vol. 45, no. 1, p. 637, Mar. 2000 (Minneapolis, Minnesota).
http://www.ee.nthu.edu.tw/ccsu/


Both the rotational and the orbital motions of the earth together with the orbital
motion of the target planet contribute to the Sagnac
effect. But the orbital motion of the sun has no effects
on the interplanetary propagation. On the other hand, as
the unique propagation frame in GPS and intercontinental
links is a geocentric inertial frame, the rotational motion
of the earth contributes to the Sagnac effect.
But the orbital
motion of the earth around the sun and that of the
sun have no effects on the earthbound propagation. By
comparing GPS with interplanetary radar, it is seen that
there is a common Sagnac effect due to earth’s rotation
and a common null effect of the orbital motion of the sun
on wave propagation.
However, there is a discrepancy in
the Sagnac effect due to earth’s orbital motion. Moreover,
by comparing GPS with the widely accepted interpretation
of the Michelson–Morley experiment, it is seen that
there is a common null effect of the orbital motions on
wave propagation, whereas there is a discrepancy in the
Sagnac effect due to earth’s rotation.
Based on this characteristic of uniqueness and switchability of the propagation frame,
we propose in the following section the local-ether model
of wave propagation
to solve the discrepancies in the in-
fluences of earth’s rotational and orbital motions on the
Sagnac effect and to account for a wide variety of propagation
phenomena.
Anyway, the interplanetary Sagnac effect is due to
earth’s orbital motion around the sun as well as earth’s
rotation. Further, for the interstellar propagation where
the source is located beyond the solar system, the orbital
motion of the sun contributes to the interstellar Sagnac
effect as well.
Evidently, as expected, the proposed local-ether model
accounts for the Sagnac effect due to earth’s rotation and
the null effect of earth’s orbital motion in the earthbound
propagations in GPS and intercontinental microwave link
experiments. Meanwhile, in the interplanetary radar, it accounts
for the Sagnac effect due both to earth’s rotation
and to earth’s orbital motion around the sun.
Based on the local-ether model, the propagation is entirely
independent of the earth’s orbital motion around
the sun or whatever and the velocity v for such an earthbound
experiment is referred to an ECI frame and hence
is due to earth’s rotation alone.
In the original proposal,
the velocity v was supposed to incorporate earth’s orbital
motion around the sun. Thus, at least, v2/c2
=~ 10-8. Then the amplitude of the phase-difference variation
could be as large as π/3, when the wavelength is
0.6 µm and the path length is 10 m. However, as the velocity
v is the linear velocity due to earth’s rotation alone,
the round-trip Sagnac effect is as small as v2/c2∼ 10-12 which is merely 10-4 times that due to the orbital motion.The Sagnac effect is a FIRST ORDER effect in v/c.
Even in the round-trip nature of the Sagnac effect, as it was applied in the Michelson-Morley experiment, thus becoming a second order effect within that context,
we can see that the ORBITAL SAGNAC IS 10,000 TIMES GREATER than the rotational Sagnac effect.More information on Dr. C.C. Su's paper on the orbital Sagnac effect.
His paper was also published by HARVARD UNIVERSITY:
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?2001EPJC...21..701SSee the headline at the top:
NASA ADS Physics/Geophysics Abstract Service
So far, Dr. C.C. Su's papers, which include the correct orbital Sagnac calculations, based on a circular loop with the center of rotation located at the Sun, have been published by:
HARVARD UNIVERSITY
BULLETIN OF THE AMERICAN PHYSICAL SOCIETY
EUROPEAN PHYSICAL JOURNAL
EUROPHYSICS LETTERS JOURNAL
JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS
Further information here:
http://www.ee.nthu.edu.tw/ccsu/Journal of Electromagnetic Waves and Applications:
http://www.ee.nthu.edu.tw/ccsu/qem/f3c.pdfFor the interplanetary propagation, earth’s orbital
motion contributes to the Sagnac effect as well. This local-ether model
has been adopted to account for the Sagnac effect due to earth’s
motions in a wide variety of propagation phenomena, particularly the
global positioning system (GPS), the intercontinental microwave link,
and the interplanetary radar.
The peer reviewers at the Journal of Electromagnetic Waves and Applications agree that the orbital Sagnac is larger than the rotational Sagnac, that it is missing, and that a local-ether model has to be adopted in order to account for this fact.
The solar gravitational potential effect upon the GPS clocks is also missing:https://www.theflatearthsociety.org/forum/index.php?topic=30499.msg1846706#msg1846706This means that the hypotheses of the RUDERFER EXPERIMENT are totally fulfilled:
https://www.theflatearthsociety.org/forum/index.php?topic=30499.msg1846721#msg1846721Ruderfer, Martin (1960) “First-Order Ether Drift
Experiment Using the Mössbauer Radiation,”
Physical Review Letters, Vol. 5, No. 3, Sept. 1, pp
191-192
Ruderfer, Martin (1961) “Errata—First-Order Ether
Drift Experiment Using the Mössbauer Radiation,”
Physical Review Letters, Vol. 7, No. 9, Nov. 1, p 361
in 1961, M. Ruderfer proved mathematically and experimentally, using the spinning Mossbauer effect, the FIRST NULL RESULT in ether drift theory.
A GPS satellite orbiting the Earth, while at the same time the entire system is orbiting the Sun, IS A LARGE SCALE SPINNING MOSSBAUER EXPERIMENT.
Given the very fact that these GPS satellites DO NOT record the orbital Sagnac effect, means that THE HYPOTHESES OF THE RUDERFER EXPERIMENT ARE FULFILLED.
Why is there no requirement for a Sagnac correction due to the earth’s orbital motion? Like the transit time in the spinning Mossbauer experiments, any such effect would be completely canceled by the orbital-velocity effect on the satellite clocks.
However, indirectly, the counteracting effects of the transit time and clock slowing induced biases indicate that an ether drift is present. This is because there is independent evidence that clocks are slowed as a result of their speed. Thus, ether drift must exist or else the clock slowing effect would be observed.
In fact, there is other evidence that the wave-front bending and absence of the
Sagnac effect in the earth-centered frame is due to the clock-biasing effects of velocity
and that an ether drift velocity actually exists in the earth-centered frame. First, the
gradient of the solar gravitational effects upon clocks on the surface of the earth is such
that the clocks will speed up and slow down in precisely the correct way to retain the
appropriate up-wind and down-wind clock biases. Thus, the clocks must be biased or
else the solar gravitational effects would become apparent.
A total refutation of your false claims, and a total debunking of the false beliefs held by the authors of the Stellarium software.