If you are still having problems with Starlight then there are other tools you can use to increase this. The Spectral Relay is a multiblock structure. Full instructions on how to build this can be found in your Tome on page 2 of the Relay, on the top right of the left page. Hovering over the star will give you a full list of materials needed. Once the foundation is built, place down the Relay and the right-click the relay with a Glass Lens.
You need to build this multiblock structure near (14 blocks away from the Altar is the max distance) your Luminous Crafting Table. More than one can be built to increase their power, and they can be built adjacent to one another so that they share sides as shown below.
However as cool as this is, this is also a very inefficient setup due to Astral Sorcery’s starlight cannibalism mechanic, where any starlight collector (Crystal’s, Ritual Pedestals, Relays, etc.) operates most efficiently within its own 16 block area, edges determined by vectors. For example the second relay will add minimal, and probably immaterial amounts of starlight to the network. It will be significantly improved if the second relay was placed at least 16 blocks away from the other Relay.
For further reinforcement of the dangers of starlight cannibalism to every budding Astromancer out there, the official Astral Sorcerers guild has prepared the following image:
You can still put down a whole bunch of these relays (and later on Collector Crystals / Enhanced Collector Crystal structures) which will increase your starlight power. Just make sure there is only one Luminous Crafting Table in their line of sight, that they are not being blocked by walls, and once again, all starlight collecting devices function most efficiently when at least 16 blocks away from each other.