|
|
The Digitalisation of the Maksutov Camera 350/840 of the Observatory in Úpice
Rail, Zdeněk ; Melich, Zbyněk
The Maksutov chamber with a diameter of 350 mm and a focal length of 840 mm was manufactured in Turnov in the early 1980s. At the Úpice Observatory it was used to photograph the sky for photographic film. Currently, we have been asked to convert it to a digital device. It was necessary to design and manufacture a correction element for the chamber to straighten its focal surface and to equip it with a suitable digital camera. In this work we present description of modification of this device.
|
|
| |
|
| |
|
|
Large displacement and deformation measurement by frequency sweeping digital holography
Psota, P. ; Lédl, Vít ; Kaván, František ; Matoušek, O. ; Doleček, R.
Recently, a digital holographic method called Frequency Sweeping Digital Holography (FSDH) for high precision measurements of surface topography of mechanical parts has been introduced. The greatest advantage of the presented FSDH is the fact that the measurement is absolute. i.e. optical path difference is independently retrieved in every single pixel. This approach can therefore be used also for measurement of large displacements and deformation. FSDH is particularly suitable in cases where the common digital holographic methods fail due to e.g. 2π unambiguity problem or speckle decorrelation. Measurement method principles, setup details, an some features of the method are discussed.\n
|
|
|
Use of holography for surface measurement and characteriaztion
Kaván, František
This research focuses on the use of digital holography for measuring the shape of optical and other surfaces. For the first experiments, we used a standard double-wave holographic interferometry method. This served as a reference. However, the main focus is Frequency Sweeping Digital Holography (FSDH), or scanning digital holography, which utilizes fluently translatable DFB laser diodes. The accuracy of this method can be further improved by combining measurements from multiple wavelengths - multiple diodes. When combined, this method can achieve accuracy of up to 2 μm.
|
|
| |
|
| |
|
| |
|
| |
|
|
Attaining surface homogeneity in the deposition of complex layer systems
Žídek, Karel
We report on a procedure of optimization of a thin-film deposition process with respect to the best attainable layer homogeneity on a large deposited surface. By using a deposition mask and rotation of the deposition calotte, we reach the homogeneity of ± 0.5% for samples with the diameter up to 5 cm. Furthermore, we investigate the effect of substrate tilt and of a deposition on a curved lens surface with respect to homogeneity of the deposited layer.
|
guest ::
