Indeed, LeGrande's theory of diurnal lag has very interesting astronomical implications. Let us consider some.
Pluto's present "apparent" position is in Sagittarius. But it takes light about 5.5 hours to get here from Pluto. Thus, according to the diurnal lag theory, Pluto's "actual" position is not in Sagittarius at all.
Astronomers tend to consider Rigel as being in Orion. But that's merely Rigel's apparent position. Rigel is 800 light-years from the Earth, hence according to LeGrandean astronomy, Rigel's "actual" diurnal position leads by 800 years. In other words, when you look at Rigel, you must keep in mind that this is merely the apparent image -- the real Rigel has rotated around the Earth 292,000 times already.
Suppose the sun was 173.5 AU from the earth. At this distance, it would take 24 hours for light to travel from the sun to the earth. According to LeGrande's theory of diurnal lag, this would cause the sun's "actual" position to lead its apparent position by 24 hours. So, the "actual" position would be the same as the apparent position. The sun would actually be where it apparently is. Furthermore this would be the case if the sun's distance were any multiple of 173.5 AU.
Only if you consider a stopped clock to be right twice a day : )