The asteroid was discovered on 22 August 1987, by American astronomer Eleanor Helin at the Palomar Observatory in California, United States.
[2] Armaghobs orbits the Sun in the inner main-belt at a distance of 1.6–3.0 AU once every 3 years and 6 months (1,282 days).
[6] In February 2013, a rotational lightcurve of Armaghobs was obtained from photometric observations by Kevin Hills at the Riverland Dingo Observatory at Moorook, South Australia.
Lightcurve analysis gave a rotation period of 24.978 hours with a brightness variation of 0.51 magnitude (U=2).
It is also known for the invention of the cup-anemometer by Thomas Robinson, the New General Catalogue compiled by John Dreyer, and Lindsay's Armagh-Dunsink-Harvard telescope.