Publications of the Astronomical Society of the Pacific.

Article discussing the early design and features of Lowell Observatory.

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The MMT Observatory, a joint venture of the Smithsonian Institution and the University of Arizona, operates the 6.5-m MMT telescope on the summit of Mount Hopkins approximately 45 miles south of Tucson, AZ. The upgraded telescope has been in routine operation for nearly fifteen years and, as such, is a very reliable and productive general purpose astronomical instrument. The telescope can be configured with one of three secondary mirrors that feed more than ten instruments at the Cassegrain focus. In this paper we provide an overview of the telescope, its current capabilities, and its performance. We will review the existing suite of instruments and their different modes of operation. We will describe some of the general operations challenges and strategies for the Observatory. Finally, we will discuss plans for the near-term future including technical upgrades, new instrumentation and routine queue operation of MMIRS and Binospec.

Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Over 100 tons of material enters the Earth's atmosphere every day, mostly in the form of meteoroids less than a millimeter across. As a meteoroid enters the atmosphere, it ablates and forms a plasma. Radars can detect this plasma, which travels at approximately the same speed as the meteoroid, as a head echo. Such observations can determine the speed and trajectory of a meteoroid with high accuracy. A better characterization of these small particles will contribute to our understanding of the Earth's atmosphere, the solar system, and the local interstellar medium. Meteoroids provide a source of heavy metals at high altitudes that impact atmospheric chemistry and physics. Greater knowledge of the composition and masses of meteoroids will help astronomers understand the material within the solar system and the local interstellar medium. This dissertation focuses on meteoroid head echo observations using the 50 MHz radar at the Jicamarca Radio Observatory. These provide high resolution observations in both range and time. We use this data to evaluate methods of determining meteoroid properties and introduce a technique to determine meteoroid mass which involves fitting range and velocity measurements to an ablation model. This technique is compared with some established mass estimation methods, including scattering mass theory. We find the overall mass distribution for observed meteoroids as well as the spatial distribution of these particles. The peak of our mass distribution, at approximately 10^-11 kg, is significantly lower than what is found using specular meteor radars. We illustrate how the spatial distribution varies with meteoroid mass, and how different meteoroid sources appear when different mass ranges are examined. For the smallest meteoroids, only the Apex sources are detected, while all six of the dominant meteor sources are observed with comparable intensity when examining meteors with a mass larger than 10^-9 kg. We also directly compare meteor data taken with the 50 MHz radar to observations using a specular meteor radar in a novel experiment using both instruments simultaneously. / 2031-01-02

Our life experience can be enriched by observation; acknowledging this as a way of "seeing" can positively influence architectural design. This thesis records personal observation of light and looks to historical precedents in which natural light is revered as an element that both defines space and emphasizes importance of place. The culmination of this course of study is a project for light in which a monumental sundial becomes an amphitheater for the town of Newport, Virginia. / Master of Architecture

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Cultural identity today has become deterritorialized. As mass migration, mobility and interconnectivity between peoples and regions have increased, connections to geographical roots have loosened. People today are enmeshed in multiple spatial contexts, their past and present associations all contribute to shaping an identity that reaches beyond territorial boundaries. Being simultaneously a part of and apart from a multitude of places allows for identity to be situational and hybrid, between categorization. To examine the fluidity of identity and its relationship to the built environment, this investigation focuses specifically around the Indian diaspora, tracing the relationship between people and place within their homeland, through transition, and after settling in a new hostland. While definitions of nationalism typically involve identifying ethnic commonalities within a state, the Indian nation unites in a celebration of disparity. As India developed as a home to numerous languages, social hierarchies and belief systems, it has struggled to form a coherent national narrative. The overseas Indian community amplifies this dilemma as they are confronted with further multiplicity in a foreign environment. The result is a gap that prevents the Indian diaspora from fully connecting to both homeland and hostland, situating them in a space of the in-between. Rather than attempting to bridge this gap, this investigation chronicles the reasons for its existence and offers an observatory as a space in the built environment where the gulf between cultural identities can be explored.

In this thesis I present the results of a periodicity study on the neutrino data collected over the span of the first two phases of SNO, at both low (1 day⁻¹ - 0.1 yr⁻¹) and high (1 day⁻¹ - 0.1 min⁻¹) frequency ranges. The high frequency study is the first of its kind, and is of particular interest in that it opens a window into the detection of solar g-mode oscillations, which have never been conclusively experimentally verified. In a data set with 7,646 neutrino candidates over a period of 698.29 live days, there was no detected high-frequency periodic signal. In addition to a wide-range, single-peak high-frequency search, I have performed a directed-region frequency analysis, and a noise-motivated broad-band analysis. All searches indicate an absence of periodicity in the 8B solar neutrino signal as measured by SNO. I have also carried out an analysis of time dependence in the context of a trigger-less burst search, with the motivation of either observing neutrinos from an optically occluded supernova, or setting an upper limit on the senstitivity of our detector for such an observation. I include discussions of backgrounds to such a search that are specific to a heavy-water Cherenkov detector such as SNO. / text

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