811,500,000 tablespoons is about 0.000000003 times as big as Halley's Comet
In other words, it's 0.00000000300 times the size of Halley's Comet, and the size of Halley's Comet is 330,000,000 times that amount.
(Comet Halley, officially "1P/Halley") (volume calculated based on 2005 dimensions)
Halley's Comet, the famous comet visible to observers on Earth approximately every 76 years, has a peanut- or potato-shaped nucleus made of rock, dust, ice, and various frozen gasses. The nucleus measures approximately 15 km by 8 km by 8 km, which yields a calculated volume of 270,000,000,000,000,000.00000000000000000000 tablespoons. The coma of the Comet — the trail of sublimated gasses that give the Comet its visibility — may be up to 100,000 km in length.