(6156) Dall Main-belt Asteroid

Discovered on 12 January 1991 by B. G. W. Manning at Stakenbridge.

Named in memory of Horace E. Dall (1901–1986), a talented craftsman known internationally for his skill in instrument making, optics and optical design. Inventor of the Dall null test for parabolic telescope mirrors and coinventor of the Dall-Kirkham Cassegrain-type telescope, Dall was well known for his Maksutov telescopes, in particular a six-inch-aperture folding model that he used to take on his world travels. Dall refigured many telescope objective lenses to give optimum resolution, and he was also well known for making high-power microscope objectives. Dall joined the British Astronomical Association in 1925 and was awarded its Walter Goodacre Medal in 1967.Naming citation (WGSBN Bull. 3, #14, 4), IAU / Minor Planet Center, via NASA/JPL

Where Dall is today

Seen from above the solar system on 2026-10-14: Dall is 2.79 au from the Sun and 2.51 au from Earth. Computed from JPL's orbital elements.

Facts

Number	6156
Provisional designation	1991 AF1
Orbit class	Main-belt Asteroid
Diameter	10.8 km (#4,671 largest of 17,440 named asteroids with a measured size)
Albedo	0.182
Absolute magnitude (H)	12.54
Orbital period	5.18 years
Semi-major axis	2.99 au
Perihelion – aphelion	2.78 – 3.21 au
Eccentricity	0.0712
Inclination	9.43°
Closest distance between its orbit and Earth's (MOID)	1.80 au

Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.

Also discovered on 12 January 1991

More named asteroids discovered by B. G. W. Manning

All 18

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