MegaPipe astrometry for the New Horizons spacecraft

TL;DR

This paper presents a high-precision astrometric reference frame for the New Horizons spacecraft's approach to Pluto, utilizing MegaPrime data and UCAC4 catalog to achieve 0.02 arcsecond accuracy.

Contribution

It introduces a novel method combining MegaPrime imaging and UCAC4 catalog to enhance astrometric precision for spacecraft navigation near Pluto.

Findings

Achieved 0.02 arcsecond residuals in astrometric catalog

Successfully used galactic plane field for dense reference frame

Enabled precise navigation for New Horizons approach

Abstract

The New Horizons spacecraft, launched by NASA in 2006, will arrive in the Pluto-Charon system on July 14, 2015. There, it will spend a few hours imaging Pluto and its moons. It will then have a small amount of reserve propellant which will be used to direct the probe on to a second, yet to be discovered object in the Kuiper Belt. Data from the MegaPrime camera on CFHT was used to build a precise, high density astrometric reference frame for both the final approach into the Pluto system and the search for the secondary target. Pluto currently lies in the galactic plane. This is a hindrance in that there are potential problems with confusion. However, it is also a benefit, since it allows the use of the UCAC4 astrometric reference catalog, which is normally too sparse for use with MegaCam images. The astrometric accuracy of the final catalogs, as measured by the residuals, is 0.02 arcseconds.