occultations

"occult" science at LCOGT

Our newly-commissioned Lucky Imaging and High Speed Photometry (LIHSP) cameras on FTN and FTS scored a great success on June 23rd at their first attempt to collect science data, catching occulations of both Pluto and its satellite Charon from FTN!  An "occultation" is simply the transit of an object along the line of sight to a star, From occultations of Kuiper Belt Objects, you can learn about their size, and a for large one like Pluto, its atmosphere and or

Upper Limits on the Number of Small Bodies in Sedna-Like Orbits by the TAOS Project

We present the results of a search for occultation events by objects at distances between 100 and 1000 AU in light curves from the Taiwanese-American Occultation Survey. We searched for consecutive, shallow flux reductions in the stellar light curves obtained by our survey between 2005 February 7 and 2006 December 31 with a total of ~4.5 × 10^9 three-telescope simultaneous photometric measurements. No events were detected, allowing us to set upper limits on the number density as a function of size and distance of objects in Sedna-like orbits, using simple models.
The Astronomical Journal 138 1893, doi: 10.1088/0004-6256/138/6/1893

The TAOS Project: High-Speed Crowded Field Aperture Photometry

We have devised an aperture photometry pipeline for data reduction of image data from the Taiwanese-American Occultation Survey (TAOS). The photometry pipeline has high computational performance, and is capable of real-time photometric reduction of images containing up to 1000 stars, within the sampling rate of 5 Hz. The pipeline is optimized for both speed and signal-to-noise performance, and in the latter category it performs nearly as well as DAOPHOT. This paper provides a detailed description of the TAOS aperture photometry pipeline.
Publications of the Astronomical Society of the Pacific, 121:1429–1439, 2009 December

The TAOS Project: Upper Bounds on the Population of Small Kuiper Belt Objects and Tests of Models of Formation and Evolution ...

We have analyzed the first 3.75 years of data from the Taiwanese American Occultation Survey (TAOS). TAOS monitors bright stars to search for occultations by Kuiper Belt objects (KBOs). This data set comprises 5 × 105 star hours of multi-telescope photometric data taken at 4 or 5 Hz. No events consistent with KBO occultations were found in this data set. We compute the number of events expected for the Kuiper Belt formation and evolution models of Pan & Sari, Kenyon & Bromley, Benavidez & Campo Bagatin, and Fraser.
The Astronomical Journal, Volume 139, Issue 4, pp. 1499-1514 (2010).

An observation of a mutual event between two satellites of Uranus

We present observations of the occultation of Umbriel by Oberon on 2007 May 4. We believe this is the first observed mutual event between satellites of Uranus. Fitting a simple geometric model to the light curve, we measure the mid-event time with a precision of 4 s. We assume previously measured values for the albedos of the two satellites, and measure the impact parameter to be 500 +/- 80 km. These measurements are more precise than estimates based on current ephemerides for these satellites. Therefore observations of additional mutual events during
Hidas, M. G., Christou, A. A., & Brown, T. M. 2008, MNRAS, 384, L38