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**Tom Roberts**

wrote:
3 Deviation of stars light by Sun is optical

Much of what you say is well known. But some parts are just plain wrong,
and you come to a completely incorrect conclusion. OF COURSE a solar
atmosphere could be a lens for light that passes close to the sun; the
issue is: how large of an effect is this compared to the predicted
effect of GR? Numerous other computations come to the opposite
conclusion -- it is much smaller than the GR effect.

First, note that we can MEASURE the density of gas from the sun near the
earth, and from that compute its index of refraction and know its
effects are negligible near and outside the orbit of earth. Yet VLBI
observations show gravitational lensing from the sun at angles greater
than 90 degrees from the sun -- for which the line-of-sight to the
distant object is always further from the sun than is the earth, and
therefore the effects due to the index of refraction of the solar
atmosphere are negligible. Like observations near the sun, these are in
good agreement with the predictions of GR.

Second, your argument about lack of dispersion is just plain wrong. Yes,
for a casual observer looking into a prism with a wide light beam
entering, no color separation is observed in the middle of the beam. But
that is not what astronomers do. Astronomers have highly directional
telescopes, and if you looked into that prism with micro-radian
precision you would indeed see color separation (in effect the angular
resolution of the telescope turns the wide input beam into a narrow
one). Your eyes are not telescopes, and do not have the requisite
angular resolution; modern astronomical instruments do.

Neither Shapiro delay nor the gravitational lensing by the sun are
explained by the atmosphere of the sun. Indeed, simple arguments based
on the equivalence principle show there must be SOME gravitational
lensing; they obtain only half the observed effect because they don't
take into account the full geometrical effects of gravitation.

And, of course, if you insist on it being optical effects, you must TUNE
the "effects" you claim to be almost precisely the values predicted by
GR -- unless you have an independent method of computing the index of
refraction(etc.), you have no leg to stand on; your paper gives no such
independent computation. Until you can justify your claim that optical
effects are MUCH larger than other computations of them, your claims are
irrelevant.

Tom Roberts