CCD monitoring of flare stars in stellar aggregates

2005

We discuss photometric calibration techniques of the CCD images using bias, dark and flat-field frames. Description and properties of the individual calibration images are given. Procedures for creating of high-precision master calibration frames are described.

Serbian Astronomical Journal, 1998

36 micrometric measurements of 20 double or multiple systems carried out with the Zeiss 65/1055 cm Refractor of Belgrade Observatory are communicated. Also 35 CCD measurements of 15 double or multiple systems are included.

Astronomical & Astrophysical Transactions, 2003

As a result of the cooperation between the Sofia Sky Archive Data Center (Bulgaria) and Bamberg Observatory (Germany), Royal Observatory of Edinburgh (UK), Konkoly Observatory (Hungary), Strasbourg Observatory, Institute of Astronomy in Cambridge (UK), etc., a programme for investigation of the long-term behaviour of the Pleiades active dwarf stars (in particular, flare stars) is in progress. Existing plates in the Pleiades are found in different European plate archives, made since the end of the nineteenth century, by the searching tool of the wide-field plate database (http:==www.skyarchive.org), which provides detailed information for astronomical plate archives all over the world, as well as for plates themselves. We investigate the Pleiades flare stars (UV Cet-type stars) included in the flare Stars database and identified in the USNO A2.0 catalogue. 68 Pleiades plates are already digitized with different scanning machines such as PDS 1010 (Sofia), PDS 2020 (Münster), SUPER COSMOS (Edinburgh), APM (Cambridge), UMAX 3000 (Budapest) and Epson (Berlin).

A summary is given in some details on the Alawy Stellar CCD Photometry (ASCCDP) method suggested by ([1], Paper I). The method has been investigated looking for its limitations. Some modifications have been proposed to assign the detection threshold by the user. Stellar image simulation has been invoked to test the method capability for recognising close stellar images. It has been realised that the method is able to identify correctly images of two stars whose separation is equal to the Rayleigh resolving limit. Lower than this limit the method can recognise stars with acceptable accuracy under certain condition.

On the basis of the first images obtained by using a CCD camera, SBIG ST-10ME, with the Zeiss 65/1055 cm Refractor of Belgrade Observatory it is possible to notice the advantages offered by using this camera in the realisation of Double-Star-Measuring Programme. The parameters of the limiting possibilities concerning the Large Refractor and Belgrade conditions are communicated.

The Astronomical Journal, 2020

We announce the public release of 141,531 moderate-dispersion optical spectra of 72,247 objects acquired over the past 25 years with the FAST Spectrograph on the Fred L. Whipple Observatory 1.5-meter Tillinghast telescope. We describe the data acquisition and processing so that scientists can understand the spectra. We highlight some of the largest FAST survey programs, and make recommendations for use. The spectra have been placed in a Virtual Observatory accessible archive and are ready for download.

This paper is a companion to my other two publications, all three of which represent my Master's Degree final work and thesis.

2016

This work verifies the instrumental characteristics of the CCD detector which is part of the UNI astronomical observatory. We measured the linearity of the CCD detector of the SBIG STXL6303E camera, along with the associated gain and readout noise. The linear response to the incident light of the detector is extremely linear (R2 =99.99%), its effective gain is 1.65 +/- 0.01 e-/ADU and its readout noise is 12.2 e-. These values are in agreement with the manufacturer. We confirm that this detector is extremely precise to make measurements for astronomical purposes.

Publications of the Astronomical Society of the Pacific, 2002

We have designed, constructed and put into operation a large area CCD camera that covers a large fraction of the image plane of the 1 meter Schmidt telescope at Llano del Hato in Venezuela. The camera consists of 16 CCD devices arranged in a 4 × 4 mosaic covering 2.3 • × 3.5 • of sky. The CCDs are 2048 × 2048 LORAL devices with 15 µm pixels. The camera is optimized for drift scan photometry and objective prism spectroscopy. The design considerations, construction features and performance parameters are described in the following article.

Astronomy & Astrophysics, 2016

Context. This observational paper has been prepared in the context of the large multi-wavelength effort by many observers with the aim of following up the transient flaring event of V404 Cygni that took place for several weeks in 2015 June. Aims. Our main original aim was to contribute to the study of this transient source by acquiring broad-band photometric observations during its most active flaring phases. Nevertheless, after a detailed analysis of the data, several interesting results were obtained that encouraged a dedicated publication. Methods. The methodology used was based on broad-band differential CCD photometry. This outburst of V404 Cygni rendered the source a very bright target easily within reach of small educational telescopes. Therefore, the 41 cm telescope available at the Astronomical Observatory of the University of Jaén was used in this work. Results. We detected variability at different time scales, both in amplitude and colour. Individual optical flares appear every half hour on average during our 3 h long observation, although large-amplitude (∼1 mag) variations are also observed to occur on intervals as short as 10 min. Also, colour variations appear to be highly correlated in a colour-colour diagram. Another remarkable finding is the detection of time lag, from about one to a fraction of a minute between light curves in different filters (VR c I c). Conclusions. The observed behaviour is tentatively interpreted in an scenario based on the ejection of non-thermal emitting, relativistic plasmons, with their synchrotron spectra extending up to optical wavelengths. This would render some of the V404 Cygni flares very similar to those of the well-know microquasar GRS 1915+105

Proceedings of the International Astronomical Union, 2007

A summary is given in some details on the Alawy Stellar CCD Photometry (ASCCDP) method suggested by ([1], Paper I). The method has been investigated looking for its limitations. Some modifications have been proposed to assign the detection threshold by the user. Stellar image simulation has been invoked to test the method capability for recognising close stellar images. It has been realised that the method is able to identify correctly images of two stars whose separation is equal to the Rayleigh resolving limit. Lower than this limit the method can recognise stars with acceptable accuracy under certain condition.

1998

The STIS instrument was installed into HST in February 1997 during the Servicing Mission 2. It has completed checkout and is beginning its science program, and is working well. Several scientific demonstration observations were taken, illustrating some of the range of scientific uses and modes of observation of STIS.

New Astronomy, 2018

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights • We first present the light curves of ASAS J212234-4627.6 and ASAS J212319-4622.4. • With the minimum light times, we updated the linear ephemeris for the two binaries. • The results show that ASAS J212234-4627.6 is a semi-contact system with a dark spot. • The results confirmed that ASAS J212319-4622.4 is a contact system with f = 5.899%.