JPCam achieves technical first light
Engineering image obtained during the technical first light of JPCam camera, installed in the JST250 telescope at Javalambre Astrophysical Observatory. The image corresponds to a single exposure of 300 seconds in g band. Pre-reduction corrections were only applied (bias and flatfield). Neither cosmetic corrections nor further scientific calibration steps have been implemented. It shows the Andromeda Galaxy (M31), located 2.5 million light years away, and which has an angular diameter in the sky equivalent to seven full moons, being the largest extragalactic object that can be seen in the northern hemisphere. Credit: Centro de Estudios de Física del Cosmos de Aragón (CEFCA).
JPCam, installed last June at the Cassegrain focus of the 2.5m Javalambre Survey Telescope (JST250) of the Javalambre Astrophysical Observatory (OAJ), successfully achieved technical first light on the night of June 29, obtaining its first images of the sky.
In the field of professional astrophysics, the technical "first light" of a telescope or astronomical instrument is achieved when, for the first time, photons from stars or galaxies are collected and recorded by the detectors. The technical first light aims at verifying the fulfillment of the main technical performances of the system as specified in the design phase.
“Given the large field of view of the JST250 telescope, equivalent to 36 times the area of the full moon, the first observations with JPCam were aimed to verify the image quality and its homogeneity in the entire focal plane, observing areas of the sky with tens of thousands of stars in each exposure”, explained Dr. Antonio Marín-Franch, researcher at the Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Head of the OAJ and project manager of JPCam. "Despite the system was not planned to be brought to its maximum performance during this first run, we already obtained images with PSFs of only 0.88 arcseconds and a 10% homogeneity throughout the entire field of view. This demonstrates the excellent image quality provided by the system JPCam@JST250”, he said.
JPCam is the second largest astronomical camera in the world, with more than 1,200 million pixels distributed in a mosaic of 14 scientific detectors that work in high vacuum conditions and at -110 degrees Celsius. Weighting over 1.5 tons, it provides scientific image quality with high resolution across the wide field of view. So much so, that to display one of its full-scale images it would be necessary to gather up to 570 Full HD monitors. Such characteristics, together with the set of 56 unprecedented optical filters with which JPCam works, makes it one of the most powerful astronomical cameras in the world.
JPCam has been designed, constructed and funded by the J-PAS collaboration (Javalambre Physics of the Accelerating Universe Astrophysical Survey), led by CEFCA, the Spanish National Research Council through the Instituto de Astrofísica de Andalucía (IAA-CSIC), in Spain, and the National Observatory of Rio de Janeiro and the University of Sao Paulo, in Brazil. Managed by Dr. Antonio Marín-Franch (CEFCA) and Dr. Keith Taylor (Instruments4, USA), and assembled, integrated and verified by CEFCA engineering team, JPCam has been one of the major R&D&I projects of the J-PAS collaboration, that began in 2010. “The conception, design and construction of instruments such as JPCam represent a huge scientific-technical challenge. Most JPCam components and subsystems are prototypes designed and tested for the first time in this instrument”, explained Dr. Marín-Franch.
Following the technical first light, a period of commissioning and optimization of the entire telescope-instrument system aimed at reaching its maximum quality performances has begun.
Once it comes into scientific regular operation, JPCam will be mostly devoted for the J-PAS survey, a three-dimensional map of the sky visible from Javalambre, which will cover an area of 8,500 square degrees and will generate 2.5 petabytes of scientific data.
The data collected by JPCam will be of great importance for different fields of Astrophysics. J-PAS will allow to study questions such as the nature of dark energy or the history of the expansion of the Universe throughout the last 10.8 billion years, as well as the formation and evolution of galaxies, the structure and history of our Galaxy, the Milky Way, or the systematic study of asteroids in our Solar System.
PSF distribution obtained during the JPCam first on-sky tests. This image quality analysis corresponds to a 30 second exposure in the g band. No auto-guiding and no JST250 M2 IQ control were applied during the observation.
JPCam installed at the Cassegrain focus of JST250 telescope at Javalambre Astrophysical Observatory. Main JPCam subsystems have been manufactured by Teledyne-e2v (cryogenic camera), NTE-Sener (actuator system), Astro-EME & Vacuum Projects (filter and shutter unit), Astro-EME & Jaguar Precision Machine (filter tray assemblies), Bonn-shutter (shutter) and SCHOTT Suisse SA (optical filters). The instrument has been assembled, integrated and verified at CEFCA. Credit: Centro de Estudios de Física del Cosmos de Aragón (CEFCA).