The DDRAGO instrument for COLIBRI 1.3 meter telescope of the Observatorio Astronómico Nacional in San Pedro Mártir, Baja California, México, will be installed in mid-2024. The structural design of DDRAGO was carried out by applying specific techniques for the development of astronomical instruments. At this work is decribed the mass budget, errors, and mechanical tolerances developed to fulfill the scientific objectives of DDRAGO, as well as the manufacturing methods carried out to satisfy the required geometrical specifications. Also, manufacturing processes such as grinding of reference surfaces of the structural plates, CNC manufacturing, precision drilling and tapping, and anodizing are described. The mechanical assembly of the mechanical support structure was performed in two stages. The first one, for verifying the correct integration of all the structural plates with each other and with the rest of the mechanical components that are supported by it. Then, to ensure compliance with the dimensions and geometric tolerances of the assembled structure before anodizing, the general dimensional metrology was performed with the use of a coordinate machine.
Once the structure was verified and accepted, anodizing was performed. An interesting aspect of this process is that we were able to measure the dimensional difference, as well as the repeatability of the assembly process, before and after anodizing. Finally, the dimensional acceptance reports of the DDRAGO instrument structure are shown and a series of guidelines for the manufacture, assembly, integration, and validation for mechanical structures in astronomical instrumentation are proposed.
One of the challenges of astronomical instrumentation is overcoming the intermediate stages between instrument design and acceptance testing. Manufacturing, integration tasks, and especially testing to validate these instruments require specialized infrastructure. At the Instituto de Astronomía de la Universidad Nacional Autónoma de México (IA-UNAM), we have recognized the importance of investing in this infrastructure to ensure quality, cost efficiency, and timely completion. In this paper, we present the capabilities of IA-UNAM in the design, manufacturing, and metrology of optical and mechanical components that meet astronomical and aerospace quality requirements and standards. We also discuss the adaptation of spaces necessary to perform these tasks, as well as the development of methodologies and instrumentation that we have implemented for the integration and validation stages of these instruments.
ÉBANO will be a new instrument for the 84-cm telescope in the Observatorio Astronómico Nacional in Sierra de San Pedro Mártir (Baja California Norte, Mexico) that will do integral field spectroscopy over two spectral ranges of 30 nm in wavelength in an unusually large field of view of 6.5×6.5 arcsec. The technique used by ÉBANO allows a wavelength scan over a wide spectral range by tilting a narrow-band filter thus changing the central wavelength of the transmission curve. We plan to begin observations with a complete cartography of the Andromeda galaxy (M31) with a mosaic of over 250 images, a region never fully explored with spatially resolved spectroscopy. Using two different filters we will sample the spectral range that covers the lines of NII, Hα, HeI and SII, and the range that covers OIII and Hβ, which gives ÉBANO a huge scientific potential.
DDRAGO is the first light instrument for the 1.3-m COLIBRÍ robotic telescope at the Observatorio Astronómico Nacional, San Pedro Mártir, Baja California, México (OAN-SPM). COLIBRI was developed by France and Mexico in support of the Sino-French SVOM satellite with its ECLAIRs instrument, designed to provide initial follow-up of GRBs. DDRAGO will also support a much wider program of observations of transient and multi-messenger sources. It is a wide-field multi-channel imager consisting of two parts: DDRAGO and CAGIRE. DDRAGO has blue and red channels, and it also delivers an infrared beam to the CAGIRE imager which will be installed soon after. Here we briefly recall the design and discuss the prototyping, fabrication, integration, and verification of DDRAGO. The installation and commissioning of the instrument at the OAN will start shortly.
The COLIBRÍ robotic observatory is being developed for observing the optical counterparts of GRBs detected by the SVOM satellite. It will be located at the Observatorio Astronómico Nacional in San Pedro Mártir, México. The project is a collaboration between France and México. For this purpose the astronomical instrument DDRAGO is under the last phase of critical design and starting its construction. The structural design techniques applied for developing DDRAGO are described. The mechanical calculations and finite element analysis of the instrument are included and translated into their respective error budget.
KEYWORDS: Sensors, Electronics, Control systems, Power supplies, Computing systems, Charge-coupled devices, Fluctuations and noise, Telescopes, Connectors, Camera shutters
When the SVOM mission is fully operational, data from the GRB and GW locations on the sky must be sent to ground stations to study their optical counterparts. Among these telescopes is COLIBRÍ, a Franco-Mexican robotic telescope. Its diameter is 1.3m and its focal length is f/7.2. It is mainly designed to observe the counterpart in the visible and near infrared. In this paper we describe the control system of DDRAGO, the imager component of COLIBRÍ.
We present the design of the DDRAGO wide-field multi-channel imager for the 1.3 meter COLIBRÍ telescope for the Observatorio Astronómico Nacional in Mexico. The instrument has blue and red channels which have fields of 26 arcmin. It also delivers a faster infrared beam to the CAGIRE imager which has a field of 22 arcmin. The instrument is designed to provide initial follow-up of GRBs detected by the ECLAIRs instrument on the SVOM satellite. DDRAGO is a descendent of the successful RATIR imager, but the optical design is significantly more complex to allow much wider fields. We summarize the optical, optomechanical, structural, and control design
Cosmic explosions have emerged as a major field of astrophysics over the last years with our increasing capability to monitor large parts of the sky in different wavelengths and with different messengers (photons, neutrinos, and gravitational waves). In this context, gamma-ray bursts (GRBs) play a very specific role, as they are the most energetic explosions in the Universe. The forthcoming Sino-French SVOM mission will make a major contribution to this scientific domain by improving our understanding of the GRB phenomenon and by allowing their use to understand the infancy of the Universe. In order to fulfill all of its scientific objectives, SVOM will be complemented by a fast robotic 1.3 m telescope, COLIBRI, with multiband photometric capabilities (from visible to infrared). This telescope is being jointly developed by France and Mexico. The telescope and one of its instruments are currently being extensively tested at OHP in France and will be installed in Mexico in spring 2023.
The novel 9.7m Schwarzschild-Couder Telescope (SCT), utilizing aspheric dual-mirror optical system, has been constructed as a prototype medium size x-ray telescope for the Cherenkov Telescope Array (CTA) observatory. The prototype SCT (pSCT) is designed to achieve simultaneously the wide (≥ 8°) field of view and the superior imaging resolution (0.067 per pixel) to significantly improve scientific capabilities of the observatory in conducting the sky surveys, the follow-up observations of multi-messenger transients with poorly known initial localization and the morphology studies of x-ray sources with angular extent. In this submission, we describe the hardware and software implementations of the telescope optical system as well as the methods specifically developed to align its complex optical system, in which both primary and secondary mirrors are segmented. The pSCT has detected Crab Nebula in June 2020 during ongoing commissioning, which was delayed due to worldwide pandemic and is not yet completed. Verification of pSCT performance is continuing and further improvement of optical alignment is anticipated.
For the first time in the history of ground-based y-ray astronomy, the on-axis performance of the dual mirror, aspheric, aplanatic Schwarzschild-Couder optical system has been demonstrated in a 9:7-m aperture imaging atmospheric Cherenkov telescope. The novel design of the prototype Schwarzschild-Couder Telescope (pSCT) is motivated by the need of the next-generation Cherenkov Telescope Array (CTA) observatory to have the ability to perform wide (≥8°) field-of-view observations simultaneously with superior imaging of atmospheric cascades (resolution of 0:067 per pixel or better). The pSCT design, if implemented in the CTA installation, has the potential to improve significantly both the x-ray angular resolution and the off-axis sensitivity of the observatory, reaching nearly the theoretical limit of the technique and thereby making a major impact on the CTA observatory sky survey programs, follow-up observations of multi-messenger transients with poorly known initial localization, as well as on the spatially resolved spectroscopic studies of extended x-ray sources. This contribution reports on the initial alignment procedures and point-spread-function results for the challenging segmented aspheric primary and secondary mirrors of the pSCT.
We present in this article some of the techniques applied at the Instituto de Astronomía of the Universidad Nacional Autónoma de México (IA-UNAM) to the mechanical structural design for astronomical instruments. With this purpose we use two recent projects developed by the Instrumentation Department. The goal of this work is to give guidelines about support structures design for achieving a faster and accurate astronomical instruments design. The main guidelines that lead all the design stages for instrument subsystems are the high-level requirements and the overall specifications. From these, each subsystem needs to get its own requirements, specifications, modes of operation, relative position, tip/tilt angles, and general tolerances. Normally these values are stated in the error budget of the instrument. Nevertheless, the error budget is dynamic, it is changing constantly. Depending on the manufacturing accuracy achieved, the error budget is again distributed. That is why having guidelines for structural design helps to know some of the limits of tolerances in manufacture and assembly. The error budget becomes then a quantified way for the interaction between groups; it is the key for teamwork.
COATLI is a new instrument and telescope that will provide 0.3 arcsec FWHM images from 550 to 920 nm over a large fraction of the sky. It consists of a robotic 50-cm telescope with a diffraction-limited imager. The imager has a steering mirror for fast guiding, a blue channel using an EMCCD from 400 to 550 nm to measure image motion, a red channel using a standard CCD from 550 to 920 nm, and an active optics system based on a deformable mirror to compensate static aberrations in the red channel. Since the telescope is small, fast guiding will provide diffraction-limited image quality in the red channel over a large fraction of the sky, even in relatively poor seeing. The COATLI telescope will be installed at the Observatorio Astronómico Nacional in Sierra San Pedro Mártir, Baja California, México, in 2016 and will initially operate with a simple interim imager. The definitive COATLI instrument will be installed in 2017. In this work we present the general optomechanical and control electronics design of COATLI.
COATLI will provide 0.3 arcsec FWHM images from 550 to 900 nm over a large fraction of the sky. It consists of a robotic 50-cm telescope with a diffraction-limited fast-guiding imager. Since the telescope is small, fast guiding will provide diffraction-limited image quality over a field of at least 1 arcmin and with coverage of a large fraction of the sky, even in relatively poor seeing. The COATLI telescope will be installed at the at the Observatorio Astronómico Nacional in Sierra San Pedro Mártir, México, during 2016 and the diffraction-limited imager will follow in 2017.
DDOTI will be a wide-field robotic imager consisting of six 28-cm telescopes with prime focus CCDs mounted on a common equatorial mount. Each telescope will have a field of view of 12 deg2, will have 2 arcsec pixels, and will reach a 10σ limiting magnitude in 60 seconds of r ≈ 18:7 in dark time and r ≈ 18:0 in bright time. The set of six will provide an instantaneous field of view of about 72 deg2. DDOTI uses commercial components almost entirely. The first DDOTI will be installed at the Observatorio Astronómico Nacional in Sierra San Pedro Martír, Baja California, México in early 2017. The main science goals of DDOTI are the localization of the optical transients associated with GRBs detected by the GBM instrument on the Fermi satellite and with gravitational-wave transients. DDOTI will also be used for studies of AGN and YSO variability and to determine the occurrence of hot Jupiters. The principal advantage of DDOTI compared to other similar projects is cost: a single DDOTI installation costs only about US$500,000. This makes it possible to contemplate a global network of DDOTI installations. Such geographic diversity would give earlier access and a higher localization rate. We are actively exploring this option.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.