We are off to Kona at the end of April. Hoping to have success with the R for Milky Way shots. Not sure yet what lens, but I am leaning towards the Tamron 15-30mm f/2.8 G2.
Don’t know when the RF 15-35mm will come out, but Canon lenses don’t have great track record for coma in the corners with astrophotography.
Not sure if I want to spend the money on the Tammy and sell for a loss when the RF comes out or hold out for the RF and grab a lower cost fast manual prime for the stars.