Just because courses mention Egypt and Horus or Buddhism etc doesn't mean those courses even come close to explaining astrotheology.
The big struggle in this material is to open a simple and coherent discussion of the meaning of cosmic observation in ancient myth. It is a topic that is easily derailed by many swirling subterranean cultural currents. FTL is correct that many scholars provide empirical information about different religions but fail to analyse their links, especially the similarities that derive from observation of the same sky.
From the Judeo-Christian side, the injunction in Deuteronomy against nature worship has very powerful influence on scholarly and popular attitudes, leading to the pervasive idea that the historical shift to worship of a single supernatural deity involved progress towards a higher consciousness. In fact, the shift from polytheism to monotheism was more a degrading of spiritual consciousness for the sake of political control. The association between monotheism and technological progress has reinforced the linear model whereby evolution from primitive to modern in technology and economics maps to the evolution in spirituality from animism to polytheism to monotheism. Astrotheology is seen to conflict with dominant linear theories of progress. Now monotheism functions like a political wet blanket over spiritual diversity, using its position of cultural dominance to affect a condescending tone towards those who see how much human spirituality has lost in the suppression of ancient diversity.
Modern science also works to suppress astrotheology for basically irrational reasons. A main theme here is the cultural origin of science in battle against fatalistic occult movements that were important to the scientists of the Renaissance such as the Hermetic philosophers of Florence. Modern occultists give science plenty of ammunition, since popular astrology is a magical folk tradition more geared to public entertainment than to scientific knowledge. The occult is an easy target. People can say that astrotheology seeks to put human life into a cyclic framework governed by natural patterns such as the solstices and equinoxes, but that is a regress to a primitive fatalist mentality, and human life has broken free of this old idea that we are governed by the stars. Guilt by association means that any study of astrotheology is viewed within the framework of hostility to astrology, and seen as an effort to revive false stagnant irrational magical obsolete beliefs.
The trouble with these widespread forms of opposition to astrotheology is that they kick away the ladder which humanity climbed to establish our current scientific and religious paradigms. If Jesus Christ was primarily a symbol of cosmic attunement, with the alpha and omega marking the shift of the Great Year from the Age of Aries to the Age of Pisces, in line with readily available ancient observation of the time of Christ as a moment of celestial harmony between the seasons and the stars, then this fact is highly informative for understanding the emergence of Christian theology. Ignoring this fact means we stick to a partial, alienated and supernatural theory of Christian evolution, one that disrespects the ancient ability to perceive nature, ignoring their sense of wonder in creating a myth of how the observed patterns of the sky were reflected in imagined patterns on earth.
Acharya has recently discussed her relation to theosophy, a theme which some critics have used to argue she is irrational. This is a complex question. Much theosophy is quite mad, as any reading of Blavatsky's The Secret Doctrine
will quickly reveal. Blavatky has been called the founder of modern astrology, and had immense influence on all the spiritualist movements of Europe before the Second World War. However, there is also some wheat among the tares. Her key argument, shared with astrotheology, is that Abrahamic faiths stand on the shoulders of a wide deep and rich tradition of human mythology, and can only be properly understood in the broader context of culture, especially the heritage from India and Egypt. Theosophy showed that this premise is rather explosive, as it opens the way to irrational magical ideas as much as to a serious scholarly analysis.
Gerald Massey, the founder of modern astrotheology, distanced himself from Blavatsky because he felt his own serious research was tarred in the public mind with the brush of theosophical fantasy. And yet, this attitude from Massey may well have made it harder for readers to appreciate his work. The common ground between astrotheology and theosophy in a critique of the supernatural delusion of mainstream religion was lost in an emphasis on their differences. For example, Blavatksy critiques the disenchantment of the scientific world view. This critique is central to astrotheology, because the basis of myth in natural observation was used to establish a sense of deep connection between humanity and the cosmos, a connection that is lost in the de-centered Copernican focus on objective facts.
Precession of the equinox is an interesting common ground between theosophy and astrotheology, as a topic that puts humanity back at the center of cosmology, with a deep empirical scientific truth, while also establishing a natural framework for the evolution of myth. The observation of the wobble of our planet is the basis for analysis of the long term relation between culture and nature, how religion is embedded within scientific observation. Modern views, such as Carl Sagan's story of the pale blue dot, follow Galileo and Newton in removing humanity from the center of objective cosmology. Understanding of precession points a path past this decentered mentality, seeing how Christianity emerged from observation of how our planet relates to the observed cosmos, how myth tells a deep story that links us to our universe.