You either need to square it up with the Y seam or applique it to whatever fabric you want square up with. The corners should enhance the fabric in the star. If you want to applique it, you can spray it with quilt basting spray. But to keep the character of the antique top, you should hand applique the edges down. A long project either way but truly worth it. Any antique tops you don't want, send them my way. I love to finish antique quilts!