Stellar Blade GSF Evocation benefit

[Zickery]

Give the following benefits depending on SF/GSF Evocation to Stellar Blade.
SF Evocation: +4 Astronomy
GSF Evocation: +8 Astronomy

This results in two things.
1.) It pushes characters on the threshold of being able to get an extra magic damage from Stellar Blade over that threshold without guaranteeing they'll pass it unless they have decent attribute points/some investment in Astronomy already.
2.) It makes GSF Evocation Astrologians better at evoking, and means that GSF Illusion isn't the only route for increasing your Astronomy ranks.

Astrologians having a reason to enspell their staves and make them cool and glowy looking is also a just a plus in general I think. I recognize this could be strong in conjunction with GSF Illusion Project Star Chart benefits, but I don't think that's that big of a deal given it's a 4 feat cost on a generally feat starved class.