On 12 February 1991, at a distance of 14.4 AU (2.15×10⁹ km) from the Sun, Halley displayed an outburst that lasted for several months, releasing a cloud of dust 300,000 km (190,000 mi) across.
The outburst likely started in December 1990, and then the comet brightened from magnitude 24.3 to magnitude 18.9.
Halley was most recently observed in 2003 by three of the Very Large Telescopes at Paranal, Chile, when Halley's magnitude was 28.2.
The telescopes observed Halley, at the faintest and farthest any comet has ever been imaged, in order to verify a method for finding very faint trans-Neptunian objects.
Astronomers are now able to observe the comet at any point in its orbit.

In December 2023, Halley's Comet is calculated to reach the farthest point in its orbit from Sun.
On 12 February 1991, at a distance of 14.4 AU (2.15×10⁹ km) from the Sun, Halley displayed an outburst that lasted for several months, releasing a cloud of dust 300,000 km (190,000 mi) across. The outburst likely started in December 1990, and then the comet brightened from magnitude 24.3 to magnitude 18.9. Halley was most recently observed in 2003 by three of the Very Large Telescopes at Paranal, Chile, when Halley's magnitude was 28.2. The telescopes observed Halley, at the faintest and farthest any comet has ever been imaged, in order to verify a method for finding very faint trans-Neptunian objects. Astronomers are now able to observe the comet at any point in its orbit.
In December 2023, Halley's Comet is calculated to reach the farthest point in its orbit from Sun.
Halley's Comet