(This sounds like the Victorian version of Harry Potter! The costume is intended for a boy, though I suppose a man could do something similar. I'm not sure how "toga" and "sleeves" go together.)
Long velvet toga, with wide hanging sleeves, bordered with satin, bearing the signs of the zodiac in gold; high pointed velvet cap, entwined with a gold snake; wizard's wand, large spectacles, book, and telescope; long pointed shoes.
Holt, Ardern. Fancy Dresses Described, 2nd Edition, Illustrated. London: Debenham & Freebody, 1880.
Holt, Ardern. Fancy Dresses Described, 5th Edition. London: Debenham & Freebody, 1887.