Consumer-level digital single-lens reflex (DSLR) cameras are typically not used in professional astronomy because of the systematic errors present in the data as a result of the strong intra- and interpixel variations associated with each of the three different colors (RGB) of the Bayer color filter array. Nevertheless, because the cost of DSLRs compared with traditional astronomical CCDs is so much lower, they represent a potentially underexplored area of scientific quality astronomical imaging, especially in the area of wide-field transient surveys. We demonstrate an algorithm that can achieve ≈ 1 % level photometry in each of the RGB color channels from a stellar source and discuss the application of this algorithm to a ground-based transiting exoplanet survey. The algorithm primarily takes advantage of the large number of stellar sources available for statistical averaging within a single image, using a “lucky point-spread function” approach to identify sources in the image that exhibit systematic errors consistent with a chosen target from the same image. The selection of the appropriate“lucky” reference stars is accomplished through a comparison of the stellar image morphology as it appears on the Bayer array and the reference stars. These references are linearly combined to form a synthetic comparison star that can be used for differential photometry with the target. One key to the algorithm is that all data are retained at the individual pixel-level until the final differential comparison, which helps to alleviate systematic effects that might otherwise cancel each other out during the flux-summing process. We demonstrate the algorithm on HD 339461, a mV = 8.93 G0-type star on which we achieve single-percent level photometry that approaches the fundamental noise floor possible from a single camera.
PANOPTES (Panoptic Astronomical Networked Observatories for a Public Transiting Exoplanets Survey) is a citizen science project that aims to build a collaborative, worldwide network of robots that will survey the night sky for nearby transiting exoplanets. The PANOPTES units are designed to be low-cost, easy to build with a clear set of instructions, and constructed with readily available off-the-shelf hardware. As part of collaborative efforts, we have established an online forum for the PANOPTES community. The forum serves as a platform for everyone involved in PANOPTES to discuss with each other, to help troubleshoot during the build and deployment of a unit, and to provide feedback in improving the design. PANOPTES units have been built by school students, graduate students, astronomy enthusiasts, and citizen scientists from different countries. There are currently 18 units in various stages of deployment across the world, with at least seven more units being planned for construction. The degree of success of the project relies directly on the number of units spread over the world, as light curves from different units in the network will be combined to improve sensitivity and time coverage. In this paper, we provide an overview of the project, its scientific goals, community reach, current status, challenges, and future plans.
The Huntsman Telescope* is a wide field imager based on the successful Dragonfly Telescope concept.1 It consists of an array of co-aligned telephoto DSLR lenses with cooled CCD cameras. The ten 140 mm apertures have a combined collecting area equivalent to a 0.5 m class telescope but have lower stray light levels than a typical telescope of this size.1, 2 Its primary purpose is low surface brightness imaging of nearby galaxies, and it also observes exoplanet transits and other optical transients.
PANOPTES is a citizen-science based project to discover exoplanets with consumer cameras. It is open source and aims to be highly efficient at collecting photometric data by running a wide field survey using DSLR cameras and standard lenses. In the two years since the demonstration of the baseline design at SPIE 2016 the project has moved forward in getting the hardware design ready for citizen scientists and data analysis, benefiting from an influx of both professional and amateur support. At the same time the project has experienced a number of challenges related to the nature of a grassroots project with no specific institutional home. Here we present a status update to the project with a focus on the issues associated with creating, and maintaining, a successful “pro-am” astronomy project.
This talk will specifically focus on a couple of keys concepts related to the operation of PANOPTES as a distributed observatory built by a collection of professional and amateur astronomers. These concepts can largely be broken down as: software; hardware; and organizational. However, a central theme of the talk will also be the fact that PANOPTES operates without a centralized institution, which means that decisions related to software and hardware are necessarily tied into the organizational decisions. Likewise, since the project has no official operating budget but operates largely off the budgets of each individual team (in addition to a NASA/JPL grant, the attainment of which will also be discussed), the hardware decisions and the evolving landscape of commercial over-the-counter (COTC) hardware play a significant role in the operation and maintenance of the project as a whole, which in turn affects how the software is developed.
Through all of these areas PANOPTES has experienced successes and failures as well as simple deviations from original plans. As a project we have benefited enormously from the donation of time and storage on the Google Cloud Platform (GCP), allowing us to explore technologies and solutions that would otherwise be unfeasible, but as an unofficial project we have been unable to secure a permanent formal agreement with GCP, creating challenges related to the long-term viability of those software solutions.
Being a unique project that aims to be as scientifically productive as it is successful as an outreach tool, it is hoped that the talk will provide some valuable learned lessons for any future projects that hope to utilize the unique professional-amateur dynamic that exists within the field of astronomy and open-source software.
Project PANOPTES (http://www.projectpanoptes.org) is aimed at establishing a collaboration between professional astronomers, citizen scientists and schools to discover a large number of exoplanets with the transit technique. We have developed digital camera based imaging units to cover large parts of the sky and look for exoplanet transits. Each unit costs approximately $5000 USD and runs automatically every night. By using low-cost, commercial digital single-lens reflex (DSLR) cameras, we have developed a uniquely cost-efficient system for wide field astronomical imaging, offering approximately two orders of magnitude better etendue per unit of cost than professional wide-field surveys. Both science and outreach, our vision is to have thousands of these units built by schools and citizen scientists gathering data, making this project the most productive exoplanet discovery machine in the world.
The Panoptic Astronomical Networked OPtical observatory for Transiting Exoplanets Survey (PANOPTES, www.projectpanoptes.org) project is aimed at identifying transiting exoplanets using a wide network of low-cost imaging units. Each unit consists of two commercial digital single lens reflex (DSLR) cameras equipped with 85mm F1.4 lenses, mounted on a small equatorial mount. At a few $1000s per unit, the system offers a uniquely advantageous survey eficiency for the cost, and can easily be assembled by amateur astronomers or students. Three generations of prototype units have so far been tested, and the baseline unit design, which optimizes robustness, simplicity and cost, is now ready to be duplicated. We describe the hardware and software for the PANOPTES project, focusing on key challenging aspects of the project. We show that obtaining high precision photometric measurements with commercial DSLR color cameras is possible, using a PSF-matching algorithm we developed for this project. On-sky tests show that percent-level photometric precision is achieved in 1 min with a single camera. We also discuss hardware choices aimed at optimizing system robustness while maintaining adequate cost. PANOPTES is both an outreach project and a scientifically compelling survey for transiting exoplanets. In its current phase, experienced PANOPTES members are deploying a limited number of units, acquiring the experience necessary to run the network. A much wider community will then be able to participate to the project, with schools and citizen scientists integrating their units in the network.
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