We confirm previous results that orbital periods are close to the ratio of 6:4:1 (P1:P2:Charon) indicative of mean-motion resonances, but our results formally preclude precise integer period ratios. The total system mass based on Charon's orbit is 1.4570 +/- 0.0009 x 10^22 kg. The orbit of the outermost satellite, P1, has a significant eccentricity of 0.0052 +/- 0.0011. Orbits fitted to all three satellites are nearly co-planar and, for Charon and P2, have eccentricities consistent with zero. The observations were designed to produce an albedo map of Pluto but they also contain images of Charon and the two recently discovered satellites, S/2005 P1 and.

We present new astrometry of Pluto's three satellites from images taken of the Pluto system during 2002-3 with the High Resolution Camera (HRC) mode of the Advanced Camera for Surveys (ACS) instrument on the Hubble Space Telescope. Further investigations of “neat tricks using an OTCCD” are ongoing at the U.S. This is unprecedented optical astrometry of an artificial satellite.

Currently, we can reliably obtain ~0.1 arcsec astrometry, limited most likely by both residual clocking issues and available orbit elements precision. We present observations over the course of one night to demonstrate the method. GALAXY 15 is one of the WAAS satellites, for which the FAA provides extended precision orbital elements. This allows direct astrometric measurement of the moving object with respect to background stars, as well as differential photometry with respect to stars. Thus, we eliminate both star and target trails on the CCD. We put a moving target in a central cell and take normal stare-mode multiple exposures (shifting the charge for each sub-exposure), while in surrounding cells charge is shifted simultaneously in RA and DEC to compensate for motion of the background stars while the telescope tracks on the target. Charge can be shifted in either orthogonal direction in each cell independent of the other cells. The 4.8k x 4.8k OTCCD consists of an 8x8 grid of 600圆00 pixel “cells”. We use as our demonstration object a commercial geosynchronous satellite-one for which we can obtain precise orbit information to provide ground truth. The algorithm could be integrated into data processing pipelines of WFSATs to increase their response speed and detection ability to time-domain astronomical events.We utilize an orthogonal transfer CCD (OTCCD) to demonstrate precise simultaneous astrometry and photometry of a moving object. The algorithm proposed in this paper could obtain types, positions and magnitudes of celestial objects with high accuracy and cost around 0.125 second to process an image, regardless of its size. To reduce this effect, we propose to use transfer learning strategy to train the neural network with real data. Therefore, we further investigate the epistemic uncertainty of our algorithm and have found that differences of background noises and differences of point spread functions between the training data and the real would introduce uncertainties to final measurements. Because the photometry and astrometry neural network are data-driven regression algorithms, limited training data with limited diversity would introduce the epistemic uncertainty to final regression results. In this paper, we extend the ability of a deep neural network based astronomical target detection algorithm to make it suitable for photometry and astrometry, by adding two new branches. An automatic data processing algorithm which could detect celestial objects and obtain their positions and magnitudes from observed images is important for further scientific research. Wide field small aperture telescopes (WFSATs) are preferable observation instruments for time domain astronomy, because they could obtain images of celestial objects with high cadence in a cost-effective way.

Astrometry versus photometry astronomy