Academic literature on the topic 'Chabot Observatory'

Until the last century, virtually all humans knew the appearance of the dark night sky. Even unschooled urbanites knew some constellations and planets. By 1909, light pollution made authors admonish readers to do their skywatching from the countryside rather than the city. The warnings have escalated along with the light pollution. Light pollution’s effect on professional and volunteer observational astronomy, along with telescopes’ changing focal ratios, largely determine which kinds of astronomy are done in which institutions. In times and places where individuals perceive little possibility to change their culture, astronomers cope as best they can. When activism earns results in other cultural matters, astronomers sometimes become activists to fight light pollution. Chabot Observatory has felt many of these influences in its 105-year history, and they can be read in its plans for the future as well. Despite winning some battles, the war against light pollution is still being lost, so a different approach is suggested.

The open launch of new artificial intelligence tools such as ChatGPT-3.5 (Generated Pre-trained Transformer) in November 2022 by the company OpenAI -and then its update to version GPT-4 in March 2023- poses new opportunities and challenges for journalism, and especially for professionals specifically focused on information verification. This research aims to understand and analyze the perceptions generated by the irruption of ChatGPT among fact-checking professionals in Spain with the aim of identifying disadvantages and advantages in its use, professional implications and desired functionalities. The study uses qualitative methodology with in-depth interviews with professionals from all Spanish fact-checking platforms belonging to the International Factchecking Network (IFCN) and the European Digital Media Observatory (EDMO). The results conclude that the use of ChatGPT presents notable ambivalences. On the one hand, there are perceived drawbacks in issues such as the transparency and reliability of sources, the scope of the data, and the format of the responses generated. However, fact-checkers also point to a possible auxiliary use of the chatbot in the tasks of gathering information, detecting falsehoods, and producing denials. The irruption of ChatGPT has a direct impact on the work routines of the fact-checkers, which can be made more difficult, reinforced or extended. Fact-checking professionals perceive themselves as “context agents” in a new ecosystem that also obliges them to further diversify their fields of action in the fight against disinformation and to accelerate the implementation of media education actions that empower citizens in the responsible use of artificial intelligence.

We complete the census of bright distant trans-Neptunian worlds through surveying the Southern Hemisphere sky, particularly the unexplored high-latitude regions that would contain trans-Neptunian objects (TNOs) that have experienced severe scattering. In this thesis, we developed an archival TNO survey of 6,275 square degrees of sky south of the ecliptic that have more than thirty nights of observation over five years, to a limiting magnitude of 19.0 in clear. We generated our survey through an innovative analysis of the archive of more than half a million images taken between 2 March 2004 and 23 October 2009 by the Siding Spring Survey. This survey for near-Earth asteroids uses the 0.5 m Uppsala telescope at Siding Spring Observatory. Our survey took advantage of their dense temporal coverage to resample their cadence of observation into a survey for slow-moving objects. From twenty billion astronomical sources on the Uppsala images, we extracted thirteen million transient sources, computed a subset of the trillion possible Solar System orbits that these points of light could form, and produced only a few hundred potential candidate orbital arcs. This computational processing required a hundred thousand hours of CPU time. Our survey adds to the last two decades of work into understanding the cold, distant outer regions of our Solar System that lie beyond Neptune’s orbit. These regions contain varied populations of small objects. As the remnant planetesimals of the protoplanetary disk, they offer insight into the early history and evolution of the Solar System. The brightest reflect enough photons to allow spectroscopy, indicating the composition of the topmost few millimetres of the volatile ices that form the mantles of these worlds. The sixteen hundred TNOs known have been discovered through sky surveys with optical telescopes; most extensive surveys have previously focussed on the Northern Hemisphere sky. We detected no new objects in the southern sky. We defined the exact phase space of orbital parameters that was well sampled by the Uppsala TNO survey by developing a survey simulator. Examining our survey’s observation of the objects from a well-characterized synthetic population, we found we had a 90% detection efficiency of the Kuiper belt and scattered disk; seeing no objects with an absolute magnitude between our range of sensitivity of -2.5 to 3.5 limited the bright end of the TNO population distribution. We unsuccessfully attempted to characterize two of the known distant objects. Pluto’s largest moon, Charon, is suspected to have cryovolcanism-related ammonia on its surface; we observed in the L-band with Gemini North’s GNIRS spectrograph to improve the detection, but received too little telescope time to detect Charon. In contrast, little is known about the newly discovered high-inclination Centaur-like object 2012 DR30: we obtained a light-curve with the Faulkes South 2m, but found only that this object was unvarying in brightness at better than the 5% level.

We describe an affordable sodium laser beacon adaptive optics system for near IR astronomical research at the Apache Point 3.5m observatory. The successful incorporation of adaptive optics technology to major astronomical observatories for near IR and visible operation demands that these systems ultimately be: (a) functional over the entire sky, (b) affordable, maintainable, reliable, and reasonably compact, and (c) possess a well-designed user interface for ease of operation. Motivated by these considerations, we have designed a system (ChAOS) that will use a high altitude sodium beacon as a reference source. This will enable full-sky coverage as long as an 18th magnitude natural star resides within the isoplanatic patch for tip-tilt correction. The sodium star will be created with an MIT Lincoln Laboratories laser-diode-pumped sum frequency laser operating with 15W average output power at 589nm. A dc lateral shearing interferometer wavefront sensor has been designed, and is under development in our laboratory, which uses low read noise CCD arrays. Detailed calculations have been made of the performance of this wavefront sensor, a quad-cell Hartmann array system, and minimal variance (Cramer-Rao bound) wavefront sensors, for beacons formed by optimally focused Gaussian laser beams propagating through the atmosphere; results of these calculations will be summarized. A vigorous program is underway for the development of low-cost, repairable, and reliable continuous facesheet deformable mirrors. The control system, real-time wavefront digital reconstructor, and a high-voltage deformable mirror multiplex interface driver are also being built for ChAOS. An overview of these ChAOS components and the design and expectations of the integrated system will be presented.