With the great development of solar telescope, astronomers are always trying to achieve higher guiding precision, which is one of the most important technologies for the solar observation. At present, the most popular solar guiding depends on the imaging mapping, correlation procession and capture the solar image by CCD directly. In this paper, a new full disk solar guiding method based on post-focus lens obstruction are proposed. A simple structural modification has been used to improve our solar guiding measurement and even for other extended sources. It has been proved that our new method is correct and feasible after building a simulated experiment system and running lots of experiment tests.
KEYWORDS: Sensors, Telescopes, Active optics, Astronomical telescopes, James Webb Space Telescope, Mirrors, Segmented mirrors, Space telescopes, Inductance, Large telescopes
Edge sensor is one of the most important technologies for the extremely large segmented primary telescopes like Keck, Thirty Meter Telescope (TMT), European Extremely Large Telescope (E-ELT) and Chinese Future Giant Telescope (CFGT) for control of out-of-plane degrees of freedom. Different from the capacity edge sensor from Keck and TMT, one kind of an inductance edge sensor is proposed and applied with the similar principle and configuration, fine aligned and tested in this paper to try to realize the same co-focusing or co-phasing maintenance purpose and high accuracy of relative piston and tip/tilt degrees of freedom of the segments. The sensor is also considered and modified to much more sensitive to dihedral angle between the neighboring segments. Finally some preliminary conclusions are reached.
KEYWORDS: Sensors, Active optics, James Webb Space Telescope, Telescopes, Space telescopes, Mirrors, Actuators, Segmented mirrors, Image segmentation, Astronomical telescopes
Extremely large telescopes with more and more large apertures are pursued, proposed and constructed by astronomers and technicians all over the world in the coming next years to satisfy the great demand of scientific progress. Segmented mirror active optics is the most important technology to co-phase the large primary for optically perfect segmentation. Based the experimental platform and test work in Nanjing Institute of Astronomical Optics and Technology in China, we introduce the latest co-phasing progress on fine segment support, edge sensor and close-loop co-phasing correction in China in this paper. Finally some conclusions are given based on the test results.
The real-time maintenance sensor for the active reflector is one of the key technologies for the active reflector upgradation plan of 13.7m millimeter radio telescope from Purple Mountain Observatory, China. A new type of maintenance integration sensor based on PSD and laser module based on normal angle and distance detection is proposed in this paper. After the brief introduction of the maintenance theory of the radio telescope segmented primary reflector, the method is simulated and tested on the real backup panel from the telescope in the active reflector lab in Nanjing Institute of Astronomical Optics and Technology, China. The method is proved to be a high accurate, engineering feasible for that real-time maintenance of the whole primary. Finally some conclusions are reached.
A telescope with a larger primary mirror can collect much more light and resolve objects much better than one with a
smaller mirror, and so the larger version is always pursued by astronomers and astronomical technicians. Instead of using
a monolithic primary mirror, more and more large telescopes, which are currently being planned or in construction, have
adopted a segmented primary mirror design. Therefore, how to sense and phase such a primary mirror is a key issue for
the future of extremely large optical/infrared telescopes. The Dispersed Fringe Sensor is a non-contact method using
broadband point light sources and it can estimate the piston by the two-directional spectrum formed by the transmissive
grating's dispersion and lenslet array. In this paper we introduce you the current research progress of the successful
design, construction and alignment of our dispersed Hartmann sensors together with its design principles and simulations
for indoor segmented mirror experiment system and outdoor segmented mirror experiment system. We also conduct
many successful real phasing tests and phasing corrections in the visible waveband using our existing indoor and outdoor
segmented mirror optics platform. Finally, some conclusions are reached based on the test and correction of experimental
results.
In development of large-scale astronomical telescopes, some promising new technology and method such as
honeycomb structure mirrors and silicon carbide mirrors are applied for primary mirrors. Especially in space telescopes,
the mirror lightweight design is becoming the key technology and honeycomb structure mirrors are normally required
more and more to reduce the cost and increase the feasibility of the telescopes system. In this paper, a parameter FEA
model of a two meters honeycomb structure mirror has been built, by using the engineering analysis software ANSYS.
Through this model, the structural analysis, thermal deformation analysis and the simulation active correction of low-order
frequency aberration by the finite element method have been presented.
Telescope with much larger primary can collect much more light and it is always pursued by the astronomers. Instead of
using a monolithic primary, more and more large telescopes, which are now planed or in construction, invariably adopted
segmented primary mirror. Therefore, how to sense and phase the primary mirror is the key technology. Unlike edge
sensors, which need careful calibrations, dispersed Hartmann sensor (DHS) is non-contact method using broadband point
light sources, and it can estimate piston by the two-direction spectrum formed by the transmissive grating's dispersion
and lenslet array. Thus it can realize the combination of co-focusing and co-phasing. In this paper, we introduce the
design of our dispersed Hartmann sensor together with its principle. We also manufacture a DHS sensor and do real tests
on our existing segmented mirror optics platform. Finally some conclusions are given based on the test results.
Radio telescopes with much more larger aperture collect much more signals and therefore sought after by astronomers.
The primary reflecting antenna is traditionally segmented and perfectly optically aligned at the central altitude among the
whole observation sky area for minimizing the gravitational deformation during operation and passively open-loop
maintained at any other altitude. A new laser segmentation sensing and maintaining method based on normal deflection
angle measurement is proposed in this paper. After the introduction of the theory, the method is simulated and tested on a
special prototype of radio panel segmentation system. It provides real-time monitoring and measurement of the global
segmentation status of all panels and is proved to be a high accurate, high efficient and low cost method. Finally several
conclusions are reached.
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) project has completed its engineering
work, and is going to finish commissioning around the end of 2010. The LAMOST telescope is with both large aperture
and wide field of view to achieve the large scale spectroscopic survey observation. It is an innovative large aperture
meridian active reflecting Schmidt configuration achieved by an active deformable Schmidt mirror, which could not be
realized by the traditional optical system. Its primary mirror and active Schmidt mirror are both segmented, and
composed of 37 and 24 hexagonal sub-mirrors respectively. A new active optics method succesfully developed in the
active deformable Schmidt mirror of LAMOST. It is a conbination of the thin deformable mirror active optics and
segmented active optics. This paper presents the optical performance of the telescope of LAMOST during optical test. It
is shown that LAMOST project successfully resolving the big technical challenges, and making the progress in active
optics and telescope technology.
To reduce the cost and increase the feasibility of the astronomical optical telescope, modern large optical telescope is
normally required to be as light as possible. Therefore lightweight mirror is always pursued by large telescopes
development. In this paper, a new type lightweight optical mirror blank, the evaluation of its technical feasibility and
the reduction of cost are introduced. For the purpose of applying active optics with this lightweight mirror blank, the
structural analysis, thermal analysis and optical performance simulation by the finite element method have been
presented.
Active optics is the most difficult part in LAMOST project. Especially for the segmented reflecting Schmidt plate Ma, in which both segmented mirror active optics and thin mirror (or deformable mirror) active optics are applied. To test and optimize the thin mirror active optics of Ma, and to approach the reality of operating environment of the telescope, an outdoor experiment system has been established. This experiment system is also a 'small LAMOST' with one sub-mirror of the primary mirror Mb and one sub-mirror of the Schmidt plate Ma, and with full scale in spacing (40 meters) between Ma and Mb. many parts of LAMOST were tested in the experiment system except segmented mirror active optics. Especially for force actuators, thin mirror support system, friction driving of the alt-azimuth mounting and its control system, wave front test along such a long optical path. This paper presents the experiment system, research and developments, and some experiment results.
The reflecting Schmidt plate MA of LAMOST is with 5.7m × 4.4m reflecting area and consists of 24 segmented hexagonal sub-mirrors. Each sub-mirror is 25mm in thickness and 1.1m in diagonal. To correct the spherical aberration of the primary mirror, during observation, the aspherical shape of MA should be changed in every 1.5 minutes. To achieve the good image during observation, the active support system of MA will not only create the correct off-axis aspherical shape on each sub-mirror, but also maintain the co-focus for all 24 sub-mirrors. This paper presents the studying design with finite element analysis and experiments on the active support system of MA, including its axial and lateral supports, force actuators, optimization of the stiffness of the force actuator, sub-mirror cell, the mirror support structure etc. There are 30 force actuators and three position actuators, which support each sub-mirror and connected by sub-mirror cell. Total 24 sub-mirror cells located on the top of the MA main support structure. All force actuators work as both active and passive supports for each sub-mirror. It showed that the support system is complex but should work properly within the optical requirement.
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.