A Practical alignment algorithm for Cassegrain type telescopes

Benli Öztürk, Esra
Focal plane corrected Cassegrain type optical systems have been widely used in various fields. The axial alignment of complex optical systems is not easy and a practical alignment method is needed for such systems. Tilts, decenters and axial motion of elements or group of elements in the system are the typical alignment parameters. Interferometric measurement is an effective way to see the errors caused by the misalignment of each element in an optical system. In this thesis, alignment of a Cassegrain type telescope will be examined by using interferometric measurements and modulation transfer function simulations.


Development of an optical system calibration and alignment methodology using Shack-Hartmann wavefront sensor
Adil, Fatime Zehra; Konukseven, Erhan İlhan; Balkan, Raif Tuna; Department of Mechanical Engineering (2013)
Shack-Hartmann wavefront sensors are commonly used in optical alignment, ophthalmology, astronomy, adaptive optics and commercial optical testing. Wavefront error measurement yields Zernike polynomials which provide useful data for alignment correction calculations. In this thesis a practical alignment method of a helmet visor is proposed based on the wavefront error measurements. The optical system is modeled in Zemax software in order to collect the Zernike polynomial data necessary to relate the error me...
Ozan, Ezgi Can; Tankiz, Seda; Acar, Banu Oskay; Çiloğlu, Tolga (2014-05-23)
Audio segmentation is a well-known problem which can be considered from various angles. In the context of this paper, audio segmentation problem is to extract small "homogeneous" pieces of audio in which the content does not change in terms of the present audio events. The proposed method is compared with the well-known segmentation method; Bayesian Information Criterion (BIC) based Divide-and-Conquer, in terms of average segment duration and computational complexity.
On channel capacity of FSO communication systems in anisotropic non-Kolmogorov strong turbulent atmosphere
Ata, Yalcin (The Optical Society, 2019-09-01)
Average channel capacity of free space optical (FSO) communication systems using a Gaussian beam with the intensity modulation and direct detection technique is investigated in anisotropic non-Kolmogorov strong turbulent atmosphere. The channel model is selected as gamma-gamma distribution, which is valid for strong turbulence. Obtained results show that anisotropy in both the horizontal and vertical affects the average channel capacity of an FSO communication system positively. Average channel capacity inc...
Opti-acoustic stereo imaging
Saç, Hakan; Leblebicioğlu, Mehmet Kemal; Salor Durna, Özgül; Department of Electrical and Electronics Engineering (2012)
In this thesis, opti-acoustic stereo imaging, which is the deployment of two-dimensional (2D) high frequency imaging sonar with the electro-optical camera in calibrated stereo configuration, is studied. Optical cameras give detailed images in clear waters. However, in dark or turbid waters, information coming from electro-optical sensor is insufficient for accurate scene perception. Imaging sonars, also known as acoustic cameras, can provide enhanced target details under these scenarios. To illustrate these...
Determination of optical parameters of Ga0.75In0.25Se layered crystals
IŞIK, MEHMET; Hasanlı, Nızamı (2012-05-01)
The optical properties of the Ga0.75In0.25Se crystals have been investigated by means of transmission and reflection measurements in the wavelength range of 380-1100 nm. The analysis of the results performed at room temperature revealed the presence of optical indirect transtions with band gap energy of 1.89 eV. The variation of the band gap energy as a function of temperature was also studied in the temperature range of 10-300 K. The rate of change of band gap energy (? = 6.2 x 10(4) eV/K) and absolute zer...
Citation Formats
E. Benli Öztürk, “A Practical alignment algorithm for Cassegrain type telescopes,” M.S. - Master of Science, Middle East Technical University, 2012.