Mr. Weerapot Wanajaroen Profile

Weerapot Wanajaroen

at National Astronomical Research Institute of Thailand

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Publications (6)

Proceedings Article | 30 November 2023 Presentation + Paper

Repositioning and locking method for off-axis optical system using mechanical measurement

Pongpop Sukanunta, Sarinya Jitklongsub, Maroay Phlernjai, Apirat Prasit, Weerapot Wanajaroen, Pearachad Chartsiriwattana

Proceedings Volume 12778, 127780Y (2023) https://doi.org/10.1117/12.2690412

KEYWORDS: Assembly tolerances, Tolerancing, Systems modeling, Optical components, Design and modelling, Spectroscopy, Reliability, Optics manufacturing, Mode locking, Custom fabrication

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Proceedings Article | 12 September 2021 Presentation + Paper

Design and performance of a Prime focus camera for the Thai National Telescope

Chanisa Kanjanasakul, Christophe Buisset, Thierry Lepine, Weerapot Wanajaroen, Boonrucksar Soonthornthum, Saran Poshyachinda

Proceedings Volume 11871, 118710M (2021) https://doi.org/10.1117/12.2597066

KEYWORDS: Cameras, Tolerancing, Manufacturing, Image quality, Assembly tolerances, Lenses, Telescopes

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The Thai National Telescope (TNT) is the largest telescope in Southeast Asia with a primary mirror of 2.3-meter diameter located at altitude 2457 meters, Chiang Mai, Thailand. This telescope is equipped with two photometric cameras and a medium resolution spectrometer. The maximum instantaneous field of view (FOV) is circular of diameter equal to 15 arcminutes, provided by the camera called the “TNT Focal Reducer”. In this paper, we present the design and performance estimation of a prime focus camera for the TNT with the objective to reach a FOV equal to 1 degree. The TNT prime focus camera is specified to operate over the spectral domain 0.400-0.850 μm for spectral bands g’, r’ and i’ of the Sloan Digital Sky Survey (SDSS) photometric system. This camera is designed to reach a resolution better than 2 arcseconds, slightly above the seeing limit in median atmospheric conditions. The prime focus camera is planned to be installed at the secondary mirror (M2) and mounted on a hexapod manufactured by Physik Instrumente (PI) company. This hexapod will provide a positioning accuracy of ±2.5 μm of 3-axis translation. The orientation will be adjusted with an accuracy equal to ±1.03 arcseconds of rotation. The prime focus camera comprises five lenses made of S-FPL53, N-BAK2, SF1, BAF50 and SK3. This camera includes one aspherical concave surface of conic constant equal to -0.076 and the other surfaces are spherical. We have dedicated tolerance analysis to calculate the effects of manufacturing errors, alignment errors and stability on the operational performance. The results show that the operational angular resolutions over the full field of view should be better than 1.61 arcseconds. The results of the stray light analysis show that the ghost irradiance should be five orders of magnitude smaller than the image irradiance, assuming that the second lens of the camera and the detector window have an Anti-Reflective coating of reflectivity lower than 1%.

Proceedings Article | 11 June 2021 Open Access

Hyperspectral spectro-imager survey for state of art concept identification

Weerapot Wanajaroen, Thierry Lépine, Christophe Buisset, Matthieu Castelnau, Vincent Costes, Suwicha Wannawichian, Saran Poshyachinda, Boonrucksar Soonthornthuma

Proceedings Volume 11852, 1185268 (2021) https://doi.org/10.1117/12.2600232

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Over the past twenty years, a very high number of different space hyperspectral spectrometers have been designed, developed and launched. Recently, several new compact designs based on freeform optics have been proposed in the literature. We thus considered that it was interesting to make a survey of the already existing hyperspectral imagers and innovative freeform designs to identify the most promising solutions to increase the compactness and the performance. Some surveys on hyperspectral imagers have already been done in the past. For example, the survey by Herring et al, in 1993 which proposed some hyperspectral spectrometer concepts. However, these studies are now outdated and cannot be used to identify state of art concepts. The review proposed by Kumar et al., in 2015 presented the advantages to browse the different hyperspectral imager concepts but provided only superficial technical details that cannot be used to identify the specific designs that improve both the compactness and the image and spectral qualities. We thus decided to make a bibliographic survey to analyze the most recent designs of different space hyperspectral imagers with the objective to select the concepts that will provide the best compromise between the volume and the performance. We have categorized the different systems into four groups: prism based, Offner, Three Mirror Anastigmat (TMA) and Dyson spectrometers. We analyzed these different concepts and we identified and the advantages and the drawbacks. We concluded that the most interesting state-of-art designs are the Freeform Offner, double-pass TMA and Dyson spectrometers. These designs present the most interesting performance and combine with a compact volume. We thus established a preliminary trade-off that summarizes the advantages and the drawback of these concepts. This trade-off analysis could be used as a starting point for any future study aiming at designing compact hyperspectral imager. Finally, we present the progress of some important and recent technological developments related to the manufacturing of freeform and convex gratings.

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Proceedings Article | 6 July 2018 Paper

Preliminary design and performance estimate of a prime focus camera for the 2.3m Thai National Telescope

Weerapot Wanajaroen, Christophe Buisset, Thierry Lépine, Suwicha Wannawichian, Saran Poshyachinda, Boonrucksar Soonthornthum

Proceedings Volume 10700, 107003Q (2018) https://doi.org/10.1117/12.2311931

KEYWORDS: Cameras, Tolerancing, Manufacturing, Telescopes, Lenses, Error analysis, Optical instrument design, Sensors, Optical filters, Distortion

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Proceedings Article | 6 July 2018 Paper

Design and performance estimate of a telescope dedicated to solar system planet imagery

Weerapot Wanajaroen, Christophe Buisset, Thierry Lépine, Suwicha Wannawichian, Saran Poshyachinda , Boonrucksar Soonthornthum

Proceedings Volume 10700, 107004B (2018) https://doi.org/10.1117/12.2309620

KEYWORDS: Telescopes, Active optics, Diffraction, Wavefronts, Mirrors, Error analysis, Planets, Wavefront distortions, Spatial resolution, Jupiter

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Proceedings Article | 5 March 2018 Paper

Activity status and future plans for the Optical Laboratory of the National Astronomical Research Institute of Thailand

Christophe Buisset, Saran Poshyachinda, Boonrucksar Soonthornthum, Apirat Prasit, Mary Angelie Alagao, Piyamas Choochalerm, Weerapot Wanajaroen, Thierry Lepine, Yves Rabbia, Suparerk Aukkaravittayapun, Apichat Leckngam , Griangsak Thummasorn , Surin Ngernsujja, Anuphong Inpan, Pimon Kaewsamoet, Esther Lhospice, Panomsak Meemon, Pornapa Artsang, Kajpanya Suwansukho, Wichit Sirichote, Jitsupa Paenoi

Proceedings Volume 10714, 1071407 (2018) https://doi.org/10.1117/12.2299493

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