Abstract
An orbit for Comet 122P/ de Vico, based on 400 observations in right ascension and 396 in declination, made between 20 February 1846 and 16 May 1996 but with a gap of 150 years between the 19th and the 20th century observations, is given. Linking to two orbits proved difficult until a boundary value approach was taken: link best fit orbits for the comet to a common fitting point. The linear system to be solved acquires a special form, symmetric, negative-definite, band, that permits efficient solution by square-root free Cholesky decomposition. Statistical tests indicate that the orbit is good.
