The Deep Ecliptic Survey ( DES)-a search optimized for the discovery of Kuiper belt objects ( KBOs) with the Blanco and Mayall 4 m telescopes at the Cerro Tololo Inter-American Observatory and Kitt Peak National Observatory-has covered 550 deg 2 from its inception in 1998 through the end of 2003. This survey has a mean 50% sensitivity at VR magnitude 22.5. We report here the discoveries of 320 designated KBOs and Centaurs for the period 2000 March through 2003 December and describe improvements to our discovery and recovery procedures. Our data and the data products needed to reproduce our analyses in this paper are available through the NOAO survey database. Here we present a dynamical classification scheme, based on the behavior of orbital integrations over 10 Myr. The dynamical classes, in order of testing, are ''Resonant,'' ''Centaur,'' ''Scattered-Near,'' ''Scattered-Extended,'' and ''Classical.'' ( These terms are capitalized when referring to our rigorous definitions.) Of the 382 total designated KBOs discovered by the DES, a subset of 196 objects have sufficiently accurate orbits for dynamical classification. Summary information is given for an additional 240 undesignated objects also discovered by the DES from its inception through the end of 2003. The number of classified DES objects (uncorrected for observational bias) are Classical, 96; Resonant, 54; Scattered-Near, 24; Scattered-Extended, 9; and Centaur, 13. We use subsets of the DES objects (which can have observational biases removed ) and larger samples to perform dynamical analyses on the Kuiper belt. The first of these is a determination of the Kuiper belt plane ( KBP), for which the Classical objects with inclinations less than 5 from the mean orbit pole yield a pole at R.A. = 273N92 AE 0N62 and decl. = 66N70 AE 0N20 (J2000), consistent with the invariable plane of the solar system. A general method for removing observational biases from the DES data set is presented and used to find a provisional magnitude distribution and the distribution of orbital inclinations relative to the KBP. A power-law model fit to the cumulative magnitude distribution of all KBOs discovered by the DES in the VR filter yields an index of 0:86 AE 0:10 (with the efficiency parameters for the DES fitted simultaneously with the population power law). With the DES sensitivity parameters fixed, we derive power-law indices of 0:74 AE 0:05, 0:52 AE 0:08, and 0:74 AE 0:15, respectively, for the Classical, Resonant, and Scattered classes. Plans for calibration of the DES detection efficiency function and DES magnitudes are discussed. The inclination distribution confirms the presence of ''hot'' and ''cold'' populations; when the geometric sin i factor is removed from the inclination distribution function, the cold population shows a concentrated ''core'' with a full width at half-maximum of approximately 4N6, while the hot population appears as a ''halo, '' extending beyond 30 . The inclination distribution is used to infer the KBO distribution in the sky, as a func...

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We have observed the 2002 August 21 occultation by Pluto of the R ¼ 15:7 mag star P131.1, using 0.5 s cadence observations in integrated white light with the Williams College frame-transfer, rapid-readout CCD at the 2.24 m University of Hawaii telescope. We detected an occultation that lasted 5 minutes, 9:1 AE 0:7 s between half-light points. The ''kinks'' in the ingress and egress parts of the curve that were apparent in 1988 had become much less pronounced by the time of the two 2002 occultations that were observed, indicating a major change in the structure of Pluto's atmosphere. Analysis of our light curves shows that the pressure in Pluto's atmosphere has increased at all the altitudes that we probed. Essentially, the entire pressure scale has moved up in altitude, increasing by a factor of 2 since 1988. Spikes in our light curve reveal vertical structure in Pluto's atmosphere at unprecedentedly high resolution. We have confirmation of our spikes at lower time resolution as part of observations of the emersion made at 1.4 s and 2.4 s cadence with the 3.67 m AEOS telescope on Maui.

We present a new heuristic method for minimising crossings in a graph. The method is based upon repeatedly solving the so-called star insertion problem in the setting where the combinatorial embedding is fixed, and has several desirable characteristics for practical use. We introduce the method, discuss some aspects of algorithm design for our implementation, and provide some experimental results. The results indicate that our method compares well to existing methods, and also that it is suitable for dense instances.

The Deep Ecliptic Survey is a project whose goal is to survey a large area of the near-ecliptic region to a faint limiting magnitude (R ∼ 24) in search of objects in the outer solar system. We are collecting a large homogeneous data sample from the Kitt Peak Mayall 4-m and Cerro Tololo Blanco 4-m telescopes with the Mosaic primefocus CCD cameras. Our goal is to collect a sample of 500 objects with good orbits to further our understanding of the dynamical structure of the outer solar system. This survey has been in progress since 1998 and is responsible for 272 designated discoveries as of March 2003. We summarize our techniques, highlight recent results, and describe publically available resources.