Alignment of wide field corrector against the primary mirror optical axis by spot images on auto guide cameras for prime focus spectrograph of Subaru Telescope

2018 ◽  
Author(s):  
Yuki Moritani ◽  
Naoyuki Tamura ◽  
Yoko Tanaka ◽  
Naruhisa Takato
Keyword(s):  
Optical Axis ◽  
Wide Field ◽  
Primary Mirror

LSST: making movies of AGB stars

2018 ◽  
Vol 14 (S343) ◽  
pp. 59-68
Author(s):  
Željko Ivezić ◽  
Krzysztof Suberlak ◽  
Owen M. Boberg
Keyword(s):  
Narrow Band ◽  
Field Of View ◽  
Wide Field ◽  
Northern Chile ◽  
Agb Stars ◽  
Primary Mirror

AbstractLSST (www.lsst.org) will be a large, wide-field ground-based system designed to obtain repeated images covering the sky visible from Cerro Pachón in northern Chile. The telescope will have an 8.4m (6.5m effective) primary mirror, a 9.6 sq.deg. field of view, and a 3.2 Gigapixel camera. In a continuous observing campaign, LSST will cover the entire observable sky every three nights to a depth of V ∼ 25 per visit (using 30-second exposures and ugrizy filter set), with exquisitely accurate astrometry and photometry. Close to a half of the sky will be visited about 800 times during the nominal 10-year survey. The project is in the construction phase with first light expected in 2020 and the beginning of regular survey operations by 2022. We describe how these data will impact AGB star research and discuss how the system could be further optimized by utilizing narrow-band TiO and CN filters.

Optical Design of Wide Field View and Large Relative Aperture Off-axis Three-mirror Reflective System with Tilted Optical Axis

2019 ◽  
Vol 48 (3) ◽  
pp. 322002
Author(s):  
刘强 LIU Qiang ◽  
王欣 WANG Xin ◽  
黄庚华 HUANG Geng-hua ◽  
舒嵘 SHU Rong
Keyword(s):  
Optical Axis ◽  
Optical Design ◽  
Wide Field ◽  
Field View ◽  
Reflective System

scholarly journals Non-Dimensional Star-Identification

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2697
Author(s):  
Carl Leake ◽  
David Arnas ◽  
Daniele Mortari
Keyword(s):  
Optical Axis ◽  
Focal Length ◽  
Field Of View ◽  
Wide Field ◽  
Identification Algorithm ◽  
Algorithm Performance ◽  
Star Identification ◽  
Wide Field Of View ◽  
Axis Offset ◽  
Accuracy Speed

This study introduces a new “Non-Dimensional” star identification algorithm to reliably identify the stars observed by a wide field-of-view star tracker when the focal length and optical axis offset values are known with poor accuracy. This algorithm is particularly suited to complement nominal lost-in-space algorithms, which may identify stars incorrectly when the focal length and/or optical axis offset deviate from their nominal operational ranges. These deviations may be caused, for example, by launch vibrations or thermal variations in orbit. The algorithm performance is compared in terms of accuracy, speed, and robustness to the Pyramid algorithm. These comparisons highlight the clear advantages that a combined approach of these methodologies provides.

Design and Optimize the Supporting Structure of Large-Diameter Lightweight Mirror

2012 ◽  
Vol 224 ◽  
pp. 170-173
Author(s):  
Wen Yi Chai ◽  
Yong Jie Xie ◽  
Wei Wang ◽  
Meng Yuan Wu ◽  
Xue Wu Fan
Keyword(s):  
Work Environment ◽  
Simulation Analysis ◽  
Optical Axis ◽  
Large Diameter ◽  
Primary Mirror ◽  
Supporting Structure ◽  
Final Project ◽  
Flexible Support ◽  
Ground Test ◽  
Design Requirements

This paper describe design and optimize of the lightweight primary mirror assemblies for the space telescope, aim at supporting structure of the primary mirror with an aperture of 530mm for the Cassegrain optical. We design three kinds of flexible support structure for the mirror, and numerical simulation analysis the accuracy of reflective shape for mirror assemblies on the ground test and in-orbit work environment, compare the results of analysis and optimize parameters of flexible structure, determine the final project and put it into production. The results show that the component should be aligned and tested in the same direction of the mirror optical axis and the gravity, the accuracy of reflective shape is PV<λ/25 and RMS<λ /125 (λ = 632.8nm), under the state ofΔ4oC temperature change, the RMS<λ/234 (λ = 632.8nm), the project meet design requirements of the optical system.

On the Use of Electrostrictive Actuators in Recovering the Optical Performance of the Hubble Space Telescope

1994 ◽  
Vol 360 ◽  
Author(s):  
James L. Fanson
Keyword(s):  
Hubble Space Telescope ◽  
Spherical Aberration ◽  
Wide Field ◽  
Optical Performance ◽  
Space Telescope ◽  
Jet Propulsion ◽  
Primary Mirror ◽  
Optical Correction ◽  
Active Mirror ◽  
Multilayer Actuators

AbstractThis paper describes the development of a space qualified active mirror—the Articulating Fold Mirror—which forms part of the scheme for recovering the optical performance of the Hubble Space Telescope. Three Articulating Fold Mirrors are incorporated into the optical train of the Jet Propulsion Laboratory's Wide Field and Planetary Camera-2, which was installed into Hubble by astronauts in December, 1993. Each Articulating Fold Mirror utilizes six electrostrictive ceramic multilayer actuators to precisely position a mirror in tip and tilt in order to correct the spherical aberration of the Hubble Space Telescope's primary mirror. Flight qualification aspects of the electrostrictive actuators are described. Pre- and postrepair images from the Wide Field and Planetary Camera, showing the effect of the optical correction, are presented.

scholarly journals PbS and CCD Array Autocollimation Micrometers for the Infrared Meridian Circle

1995 ◽  
Vol 167 ◽  
pp. 337-338
Author(s):  
V. N. Yershov
Keyword(s):  
Focal Plane ◽  
Optical Axis ◽  
Meridian Circle ◽  
Pulkovo Observatory ◽  
Primary Mirror ◽  
Small Constant ◽  
Ccd Array ◽  
Secondary Mirror ◽  
Axis Position ◽  
Optical Unit

A new infrared meridian instrument is being developed at Pulkovo Observatory. The main purpose of the instrument is to extend the fundamental coordinate system to the K-infrared waveband and to faint stars at visual and I-wavebands. The instrument has a 30-cm primary mirror made from astrositall. An intermediate focal plane is used to introduce luminous reference marks. One can obtain autocollimated images of the marks at the intermediate focal plane with the use of a polished chamber located around the central hole of the primary mirror. The secondary mirror of the telescope forms images of the marks and of their autocollimated counterparts and passes them to the plane of a photodetector (Fig. 1.). The luminous marks give a reference frame for the measurements. These measurements are not affected by displacements of any optical unit placed after the intermediate focal plane or by displacements of the detector. The measurements are done relative to the coordinates of the average between positions of the luminous mark and its autocollimated image. Any small constant difference between the center of curvature and the optical axis position can be determined in the laboratory.

scholarly journals A 6-metre Polar-viewing Telescope

1982 ◽  
Vol 67 ◽  
pp. 45-47
Author(s):  
E.B. Gajur
Keyword(s):  
Object Tracking ◽  
Optical Axis ◽  
Polar Axis ◽  
Primary Mirror ◽  
Celestial Pole ◽  
Fixed Orientation ◽  
Improved Performance

The construction of a 6 metre polar-viewing telescope has been proposed (Karachentsev and Gajur, 1979), based upon the use of the paraboloidal primary mirror installed originally in the 6m BTA at Zelenchukskaya and later replaced by a mirror of improved performance. The mirror would be mounted with its axis in a fixed orientation pointing to the celestial pole and observations would be made at the prime focus using instrumentation mounted on a pylon. Object tracking is then performed by rotation of the detector around the point which represents the “image” of the celestial pole. In particular, the polar axis may coincide with the optical axis of the system.

scholarly journals An Autocollimation Circle Reading System for the Infrared Meridian Instrument

1995 ◽  
Vol 166 ◽  
pp. 361-361
Author(s):  
V.N. Yershov ◽  
A.A. Nemiro
Keyword(s):  
Optical Axis ◽  
Angular Position ◽  
Optical Center ◽  
Meridian Circle ◽  
Primary Mirror ◽  
Axis Position ◽  
Spherical Mirrors ◽  
Reading System ◽  
Zero Points ◽  
New System

A new autocollimation circle reading system is proposed for the reflector meridian circle (Nemiro and Streletsky, 1988). The instrument will be used for observations in the K-infrared waveband. Instead of the divided circle fixed to the instrument tube the new system has small spherical mirrors polished at the lateral surfaces of the primary mirror. The primary mirror is made from sitall and has an autocollimation system aimed at monitoring its optical axis position. The small spherical mirrors of the circle reading system link the circle readings with the primary's optical axis. The divided circles are fixed unmovable opposite to both lateral surfaces of the primary's optical block. Both surfaces have four spherical mirrors. The distance between the divided circles and the mirrors is equal to the mirrors' radii of curvature. The scales of each circle are illuminated from outside (where the measuring microscopes are placed). The mirrors form autocollimated images of the divisions at the plane of the divisions itself. Averaged coordinates of a division and its autocollimated image give the position of the mirror's optical center, and the semi-difference of the coordinates gives the angular position of the telescope. So, the measurements of the circle positions are differential ones, and any displacements of the microscope zero-points are not critical. The precision of measurements is estimated to be better then 0.05″ (random) and 0.005″ (systematical). The work was supported by the Russian Foundation of Fundamental Investigations (the project's code is 93-02-17095).

scholarly journals Simultaneous fluorescence imaging of tilted focal planes at two depths in thick neural tissue: Implementation with remote focus in a widefield electrophysiological microscope

2019 ◽  
Author(s):  
Bruno Lagarde ◽  
Noah Russell ◽  
Elric Esposito ◽  
Laura Desban ◽  
Claire Wyart ◽  
...  
Keyword(s):  
Brain Slice ◽  
Optical Axis ◽  
Image Plane ◽  
Wide Field ◽  
Single Image ◽  
Time Required ◽  
Field Imaging ◽  
Wide Field Imaging ◽  
Neuronal Compartments

AbstractWide-field imaging conventionally results in a single image plane oriented perpendicular to the optical axis. However, in brain slice or in vivo recording, neuronal or circuit morphologies lie in arbitrarily tilted planes. Consequently the spatiotemporal advantages of wide-field non-scanned imaging are lost because of the time required for stepwise focal readjustments to view an entire neuron or network. We describe an application of remote focus that views simultaneously two planes separated by up to 100 µm, each with variable tilt from the conventional image plane. This permits fluorescence detection of ion fluxes or membrane potential across neuronal compartments and their correlation with electrical activity. Further, two fluorophores can be viewed simultaneously in each plane.We show (i) neuronal images tilted to optimise simultaneous aquisition of somatic, dendritic and axonal compartments; (ii) networks viewed simultaneously at 2 depths separated by up to 100 µm, (iii) widefield imaging at 30 Hz of Gcamp5 fluorescence during spontaneous spiking in motoneuron layers of zebrafish spinal cord separated by 30-40 microns.

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