True Visions: if you want to avoid spirit projection to keep it distinct from Shaman, you could build on Merge Sense. Maybe the astrologer creates a link to an ally (builds on the concept from Celestial Ways) and they can reach that particular ally even at great distances, but can only explore within X' radius of that ally. That might work nicely giving a role to a stealth character in the party who has to get close, working with the astrologer to get even closer. Scouting is often about one player, making them work as a team seems good.
Celestial Ways: good point about the hour duration. Doubling the bonuses is probably too much. Free spells, maybe still, especially if you increase the penalty for cancellation so the Burdened is more likely to suffer the consequences (perhaps if the spell is cancelled, they are removed from the link for the rest of the day?).
Quick summary of my Star Mage:
* Star Mastery: invisible local communication to other Star casters at 2nd level, unlimited distance to others whose star name is known at 5th, spells to get new names, to hide your name, harm someone else's name, send a waiting message, and at higher levels illuminate a large area or blast an area.
* Star Law: anti-scrying, eavesdropping, spying on other people's scrying, find the star names of others, etc.
* Star Sight: scrying which means getting the view as it is seen from above, at low levels of your own location and at high levels of any location. Setting stars to monitor for movement, record, etc.
* Star's Wisdom: bonuses to lore and information skills that would benefit from a celestial view (e.g. it will get you the rate of growth of the city but it won't get you the mayor's name), intuitions, dreams, speaking with entities beyond the world (which in this case means in orbit, on the moon, and further out into the planets).
* Weather Star: weather prediction and control, including hailstorms, lightning (from the sky), etc.
* Virtual Star?: creating relays that connect you to the sky without a direct line of site or simulate the functions of a star when the actual stars are unreachable (e.g. underground). Haven't written this list yet, not sure what else will be on it.
I also have two lists for semis, Soldier's Star and Scoundrel's Star, which provide some star and light magic that is suited to the needs of martial and stealth professions respectively. So that means for my current party of players, there is one mage with a bunch of star magic but also he can communicate with the aether knight and the dabbler (even though they haven't quite reached the level where they can initiate contact themselves beyond a hundred feet or so).