scholarly journals Astronomical Seeing at Maidanak Observatory during the Year 2018

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 38
Author(s):  
Yusufjon Tillayev ◽  
Azimjon Azimov ◽  
Aktam Hafizov
Keyword(s):  
Astronomical Observatory ◽  
Seasonal Trend ◽  
Entire Period ◽  
Image Motion ◽  
Site Testing ◽  
Previous Period ◽  
A Site ◽  
Astronomical Seeing

Results of a four-month campaign of astronomical seeing measurements at Maidanak astronomical observatory (MAO) are presented. A differential image motion monitor (DIMM) was used for seeing estimations during the period from August to November 2018. The observation was organized within the framework of a site testing for a new telescope which is going to be installed at the observatory. The median value of seeing for the entire period was determined as 0.70 arcseconds, which agrees well with the results of the period 1996–2003. The comparison of monthly values showed that some monthly median values differ from the seasonal trend of the previous period.

scholarly journals MEDIDAS DE CALIDAD DE CIELO (SEEING) USANDO LA TÉCNICA DIMM EN EL OBSERVATORIO DE HUANCAYO

2017 ◽  
Vol 23 (2) ◽  
pp. 5
Author(s):  
Erick Meza ◽  
Antonio Pereyra ◽  
Bruno Sicardy ◽  
Germán Comina ◽  
José Ishitsuka
Keyword(s):  
Temporal Evolution ◽  
Astronomical Observatory ◽  
Image Motion ◽  
Systematic Measurement ◽  
Successful Implementation ◽  
Site Testing ◽  
Palabras Clave ◽  
Astronomical Facility ◽  
Selection Of

Mostramos la implementación de un instrumento de medición de la calidad de cielo (seeing) basado en la técnica del Monitoreo del Movimiento Diferencial de Imagen (DIMM). Este instrumento permite la medición precisa y sistemática del seeing, así como su evolución temporal. Fue monitoreado el seeing en el Observatorio de Huancayo durante siete noches consecutivas de Agosto de 2012. El seeing promedio fue de 1.34” ± 0 .33”.En 14% del tiempo observado el seeing estuvo por debajo de 1”, y en 71% del tiempo, por debajo de 1.5”. El dominio de la técnica y su aplicabilidad nos permitirá usar el instrumento en varios lugares donde campañas de medición de seeing sean programadas dentro del Perú. La selección de una facilidad astronómica óptica profesional (observatorio astronómico), será favorecida con medidas DIMM futuras. Palabras clave.-Medición de la calidad de cielo, Diferencial de imagen (DIMM), Observatorio de Huancayo. ABSTRACTWe show the implementation of an instrument to measure the sky quality for astronomical purposes (seeing) using the Differential Image Motion Monitor technique. This instrument let us an acute and systematic measurement of seeing along with its temporal evolution. We monitored seeing at Huancayo Observatory during seven consecutive nights in 2012 August. Mean seeing was 1.34” ± 0.33”. In 14% of the observed time, seeing was below than 1”, and in 71% below than 1.5”. The successful implementation of this technique and its applicability let us using this instrument in several places where a program of site testing will be scheduled in Peru. The selection of a professional astronomical facility (as an astronomical observatory) will be benefited with DIMM measurements. Keywords.-Measuring qualityofsky, Differential Image (DIMM), Huancayo observatory.

scholarly journals Observations on microthermal fluctuations

1963 ◽  
Vol 19 ◽  
pp. 126-131
Author(s):  
C. R. Lynds
Keyword(s):  
Thermal Structure ◽  
Image Motion ◽  
Visual Images ◽  
Image Size ◽  
Large Telescope ◽  
Small Aperture ◽  
Large Aperture ◽  
Low Levels ◽  
A Site

The concern has been expressed many times by Dr. Bowen and others that a significant portion of the seeing deterioration may occur in levels of the atmosphere very near the ground, within a few tenths of meters of the ground. When I refer to the quality of seeing I am refering to the image size one observes in a telescope of very large aperture and I will assume that this is equivalent to image motion as observed in telescopes of very small aperture. I will not attempt a further justification for this concern; however this is the basis for the studies we are just beginning at Kitt Peak, where we will attempt to quantitatively show whether or not there is need for concern about the very low levels of the atmosphere. So we begin with the thesis that much of the poor seeing observed at a site, the enlargement of photographic or visual images as observed through a large telescope, is due to refractive inhomogeneities in the lower levels of the atmosphere, within less than 100 m above the telescope. We presume that these inhomogeneities are of local origin and that their distribution and motion is determined primarily by site topography, wind direction and velocity. The few experiments we have made thus far at Kitt Peak have been designed to ascertain quantitatively the importance of these factors. Our approach has been to make observations of the large-aperture seeing with simultaneous observations of the thermal structure of the air accessible to us immediately above the telescope.

scholarly journals Evaluation of F-Specific RNA Bacteriophage as a Candidate Human Enteric Virus Indicator for Bivalve Molluscan Shellfish

2000 ◽  
Vol 66 (4) ◽  
pp. 1280-1285 ◽  
Author(s):  
William J. Doré ◽  
Kathleen Henshilwood ◽  
David N. Lees
Keyword(s):  
Disease Outbreaks ◽  
Enteric Virus ◽  
Seasonal Trend ◽  
Human Consumption ◽  
Point Of Sale ◽  
E Coli ◽  
Reverse Transcription Pcr ◽  
The United Kingdom ◽  
Viral Indicators ◽  
A Site

ABSTRACT Escherichia coli is a widely utilized indicator of the sanitary quality of bivalve molluscan shellfish sold for human consumption. However, it is now well documented that shellfish that meet the E. coli standards for human consumption may contain human enteric viruses that cause gastroenteritis and hepatitis. In this study we investigated using F-specific RNA bacteriophage (FRNA bacteriophage) to indicate the likely presence of such viruses in shellfish sold for consumption. FRNA bacteriophage and E. coli levels were determined over a 2-year period for oysters (Crassostrea gigas) harvested from four commercial sites chosen to represent various degrees of sewage pollution. Three sites were classified as category B sites under the relevant European Community (EC) Directive (91/492), which required purification (depuration) of oysters from these sites before sale. One site was classified as a category A site, and oysters from this site could be sold directly without further processing. Samples were tested at the point of sale following commercial processing and packaging. All of the shellfish complied with the mandatory EC E. coli standard (less than 230 per 100 g of shellfish flesh), and the levels of contamination for more than 90% of the shellfish were at or below the level of sensitivity of the assay (20 E. coli MPN per 100 g), which indicated good quality based on this criterion. In contrast, FRNA bacteriophage were frequently detected at levels that exceeded 1,000 PFU per 100 g. High levels of FRNA bacteriophage contamination were strongly associated with harvest area fecal pollution and with shellfish-associated disease outbreaks. Interestingly, FRNA bacteriophage contamination exhibited a marked seasonal trend that was consistent with the trend of oyster-associated gastroenteritis in the United Kingdom. The correlation between FRNA bacteriophage contamination and health risk was investigated further by using a reverse transcription-PCR assay for Norwalk-like virus (NLV). NLV contamination of oysters was detected only at the most polluted site and also exhibited a seasonal trend that was consistent with the trend of FRNA bacteriophage contamination and with the incidence of disease. The results of this study suggest that FRNA bacteriophage could be used as viral indicators for market-ready oysters.

scholarly journals III. — Australie

1963 ◽  
Vol 19 ◽  
pp. 253-256 ◽  
Author(s):  
A. R. Hogg
Keyword(s):  
Large Telescope ◽  
Site Testing ◽  
Field Station ◽  
Distant Location ◽  
A Site ◽  
Better Than

In 1957 the Joint Observatory of Yale and Columbia Universities commenced a series of site surveys in Australia under the direction of Dr. I. Epstein. While astronomers at Mount Stromlo Observatory were greatly interested in this activity, it was not until 1958 that Mount Stromlo actively commenced site testing. Tests were initiated in the first instance with a desire to find a not-too-distant location suitable for a field station where observing conditions would be better than those at Mount Stromlo, and later with the idea of finding a site anywhere in Australia which would satisfy the needs of a large telescope.

scholarly journals Seeing Effects on Occultation Curves

1971 ◽  
Vol 2 ◽  
pp. 622-623 ◽  
Author(s):  
A. T. Young
Keyword(s):  
Diffraction Pattern ◽  
Aerial Photography ◽  
Point Of View ◽  
Image Motion ◽  
The Moon ◽  
The Earth ◽  
Stellar Occultation ◽  
Image Blur ◽  
Stellar Scintillation ◽  
Astronomical Seeing

‘Seeing’ affects the light-curve of a stellar occultation by the Moon in two ways: the diffraction pattern on the ground is smeared out by atmospheric turbulence, and the pattern also suffers random displacements. These effects are analogous to the familiar image blur and image motion, respectively. However, there is a major difference between ordinary astronomical seeing and the effect on the lunar diffraction pattern: the former is the seeing looking up at the sky from the bottom of the atmosphere, but the latter corresponds to the seeing looking down through the atmosphere at the surface of the Earth.This downward-looking seeing is of concern to people engaged in aerial photography and satellite reconnaissance, and has been studied theoretically from this point of view. It also enters into the theory of stellar scintillation, because the seeing blurs out the scintillation shadow pattern just as it blurs out the occultation diffraction pattern.

Use of AURA Microwave Limb Sounder data for Dome C and Dome A site-testing

2009 ◽  
Vol 40 ◽  
pp. 111-114
Author(s):  
A. Gardini ◽  
A. Damiani ◽  
M. Storini
Keyword(s):  
Site Testing ◽  
Dome A ◽  
A Site

scholarly journals Preliminary daytime seeing monitoring at Dome A, Antarctica

2012 ◽  
Vol 8 (S288) ◽  
pp. 296-297
Author(s):  
Chong Pei ◽  
Zhengyangg Li ◽  
Hualin Chen ◽  
Xiangyan Yuan
Keyword(s):  
Large Scale ◽  
Angular Resolution ◽  
Image Motion ◽  
Future Research ◽  
High Angular Resolution ◽  
Optical Parameters ◽  
Site Testing ◽  
Dome A ◽  
Long Period ◽  
Better Than

AbstractSites on Antarctic plateau have unique atmospheric properties that make them better than any mid-latitude sites as observatory locations. From site testing measurements over 4 years on Dome A carried out by the Chinese Center for Antarctic Astronomy, we can reasonably predict that Dome A is as good as or even better than Dome C, which has been proved to be the best astronomical site by now, and suitable for high angular resolution observations. Seeing monitoring is necessary for planning large scale ground-based optical astronomical telescopes. In 2012, the 28th Chinese Antarctic Scientific Expedition carried out preliminary daytime seeing monitoring using a Differential Image Motion Monitor (DIMM) placed at a height of 3.5m. The median seeing was found to be 0.8″. This will be the foundation of future research that obtains comprehensive and long-period monitoring of the site's optical parameters.

The PLATO Dome A site-testing observatory: Power generation and control systems

2009 ◽  
Vol 80 (6) ◽  
pp. 064501 ◽  
Author(s):  
J. S. Lawrence ◽  
M. C. B. Ashley ◽  
S. Hengst ◽  
D. M. Luong-Van ◽  
J. W. V. Storey ◽  
...  
Keyword(s):  
Power Generation ◽  
Control Systems ◽  
Site Testing ◽  
Dome A ◽  
A Site ◽  
And Control

Wave propagation effect on differential image motion monitor measurements

2019 ◽  
Vol 488 (1) ◽  
pp. 1273-1281
Author(s):  
Victor Kornilov ◽  
Boris Safonov
Keyword(s):  
Wave Propagation ◽  
Spectral Band ◽  
Image Motion ◽  
Line Of Sight ◽  
Negative Bias ◽  
Vertical Profiles ◽  
Propagation Effect ◽  
Site Testing ◽  
Weighting Functions ◽  
Turbulent Layer

ABSTRACT The differential image motion monitor (DIMM) is widely used to measure the atmospheric optical turbulence (OT) integral over the line of sight. However, it is known that because of the wave propagation effect, the DIMM’s sensitivity falls with the distance to the turbulent layer and the variance of differential image motion is only approximately proportional to the OT integral. In this paper, we study this problem using the formalism of so-called weighting functions (WFs). We develop a method for calculating these WFs, including the case of the wide spectral band of detected radiation. The effect of underestimating the OT integral for different DIMM devices involved in previous site-testing campaigns is estimated using real measurements of OT vertical profiles. For instruments with small apertures (4–6 cm), the underestimation is ≈10 per cent, whereas for larger devices with apertures of 8–10 cm, the underestimation is less than 5 per cent, on average. This leads to a negative bias in seeing estimation of 7 and 3 per cent, respectively.

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