Search

• In the photometric techniques, the intensity of the captured image is essential. • The object of specular reflection is affected by the accuracy of the photometric techniques. • In order to improve accuracy, it is necessary to design a uniform optical system. • Designate the area of non-uniformity and derive it mathematically. Photometric techniques are one of the three-dimensional image reconstruction technologies. It is used in various fields, especially surface analysis because it focuses on extracting surface information such as texture and color. Photometric techniques perform the 3D reconstruction using light sources and a camera. If the object has specular reflection properties, then an error may occur in the reconstructed data according to the noise of intensity in acquired images. For the solution of these problems, the optical system is configurated by dome light and coaxial light, and the non-uniformity area is defined and is derived by mathematical formulas in this paper. In order to verify the validity of the formulas, various simulations and experiments have been conducted. As a result, it was confirmed that the proposed optical design method could be used as a new technique for the uniform optical system. [ABSTRACT FROM AUTHOR]

Four planets have recently been discovered by gravitational microlensing. The most recent of these discoveries is the lowest-mass planet known to exist around a normal star. The detection of planets in gravitational microlensing events was predicted over a decade ago. Microlensing is now a mature field of astrophysical research and the recent planet detections herald a new chapter in the hunt for low mass extra-solar planets. This paper reviews the basic theory of planetary microlensing, describes the experiments currently in operation for the detection and observation of microlensing events and compares the characteristics of the planetary systems found to date by microlensing. Some proposed schemes for improving the detection rate of planets via microlensing are also discussed. [ABSTRACT FROM AUTHOR]

In December 2003 and January 2004, 3704 photoelectric VI C brightness measurements were made for 117 Cepheids using the SAAO 0.76 m reflector. V light curves and V–I C colour curves are presented. [ABSTRACT FROM AUTHOR]

Our photoelectric observations of two Mira variables, DW Mus and BI Sco, complemented by ASAS3 † survey data, allowed us to construct light curves for these Mira stars as well as to define their current light elements. † All Sky Automatic Survey. [ABSTRACT FROM AUTHOR]

In December 2002 and January 2003, 3206 photoelectric VIc brightness measurements were made for 97 Cephedis using the South African Astronomical Observatory 0.76 m reflector. Tables of observations together with V light curves and V - Ic colour curves are presented. [ABSTRACT FROM AUTHOR]

A total of 6083 photoelectric observations in the BVI C system, obtained between February and April 2002, are presented for 122 Cepheids located in the southern hemisphere. The main function of the photometry is to provide data that can be used to establish new epochs of maximum brightness for the Cepheids as input for the scientific study of their period changes, as well as to establish current light elements for the variables. The primary cause of period changes in Cepheids is evolution through the instability strip. [ABSTRACT FROM AUTHOR]

Photometric observations of a Near-Earth-Asteroid (NEA) 2000 DP107 were made on four successive nights during October 2000, 1.4–4.7 with the 0.6-m/0.9-m Schmidt telescope of National Astronomical Observatories, CAS (NAOC). The derived rotation period of 0.1156 day was consistent with that obtained by Pravec et al. (IAU Circular No. 7504, 2000). In addition, the relative reflectance spectrum of the asteroid covering 0.35–0.9 μm was obtained with the NAOC 2.16-m telescope adopting a low-resolution grating (10 A˚/pix) on October 2, 2000, which revealed that 2000 DP107 is an M-type asteroid. [Copyright &y& Elsevier]

We present a revised and augmented version of the Gonzalez-Perez et al. [AJ 122 (2001) 2055] catalogue of stars in quasar and blazar fields calibrated in the Landolt system. Several of the sources in this catalogue are known TeV emitters and thus of considerable interest for multifrequency campaigns. A total of 8000 measures in BVRI have been added, mostly of previously poorly observed fields giving a total of more than 20,000 measures of stars in 26 fields, in addition to the 22,000 measures of 122 field stars of 13 AGNs in JHK presented in the published catalogue. The new catalogue flags detected and possible variables (e.g., Star 8 of 3C66a which appears to be a Mira star of period 5 years). Deeper exposures have been taken of the fields of the faint gamma ray blazars PKS0528 + 13 and PKS1622 − 29, frequent targets of multifrequency monitoring campaigns, to improve the quality of their photometry. [Copyright &y& Elsevier]