A new algorithm for differential photometry: computing anoptimum artificial comparison star

2005 ◽  
Vol 326 (2) ◽  
pp. 134-142 ◽  
Author(s):  
Ch. Broeg ◽  
M. Fernández ◽  
R. Neuhäuser
Keyword(s):  
Comparison Star ◽  
Differential Photometry

scholarly journals The 2003–2004 multisite photometric campaign for the β Cephei and eclipsing star 16 (EN) Lacertae with an appendix on 2 Andromedae, the variable comparison star

2015 ◽  
Vol 454 (1) ◽  
pp. 724-740 ◽  
Author(s):  
M. Jerzykiewicz ◽  
G. Handler ◽  
J. Daszyńska-Daszkiewicz ◽  
A. Pigulski ◽  
E. Poretti ◽  
...  
Keyword(s):  
Comparison Star

scholarly journals CCD Speckle Observations of Binary Stars from the Southern Hemisphere. III. Differential Photometry

2001 ◽  
Vol 121 (3) ◽  
pp. 1583-1596 ◽  
Author(s):  
Elliott Horch ◽  
Zoran Ninkov ◽  
Otto G. Franz
Keyword(s):  
Southern Hemisphere ◽  
Binary Stars ◽  
Differential Photometry

scholarly journals Binary Star Differential Photometry Using the Adaptive Optics System at Mount Wilson Observatory

2000 ◽  
Vol 119 (5) ◽  
pp. 2403-2414 ◽  
Author(s):  
Theo ten Brummelaar ◽  
Brian D. Mason ◽  
Harold A. McAlister ◽  
Lewis C. Roberts, Jr. ◽  
Nils H. Turner ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Binary Star ◽  
Mount Wilson Observatory ◽  
Differential Photometry ◽  
Adaptive Optics System

scholarly journals Discovery of a strong magnetic field in the rapidly rotating B2Vn star HR 7355

2010 ◽  
Vol 6 (S272) ◽  
pp. 204-205
Author(s):  
Mary E. Oksala ◽  
Gregg A. Wade ◽  
Wagner L. F. Marcolino ◽  
Jason H. Grunhut ◽  
David Bohlender ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Least Squares ◽  
Strong Magnetic Field ◽  
Type Star ◽  
Longitudinal Field ◽  
Rotational Period ◽  
V Band ◽  
Large Program ◽  
Differential Photometry

AbstractWe report on the detection of a strong, organized magnetic field in the helium-variable early B-type star HR 7355 using spectropolarimetric data obtained with ESPaDOnS on CFHT by the MiMeS large program. We also present results from new V-band differential photometry obtained with the CTIO 0.9m telescope. We investigate the longitudinal field, using a technique called Least-Squares Deconvolution (LSD), and the rotational period of HR 7355. These new observations strongly support the proposal that HR 7355 harbors a structured magnetosphere similar to that in the prototypical helium-strong star, σ Ori E.

scholarly journals 20. Commission Pour l’Observation des Positions et le Calcul des Éphémérides des Petites Planètes, des Comètes, et des Satellites

1933 ◽  
Vol 4 ◽  
pp. 116-116
Author(s):  
M. A. O. Leuschner ◽  
MM. Aitken ◽  
Banachiewicz ◽  
E. W. Brown ◽  
Comas y Solâ ◽  
...  
Keyword(s):  
Special Reference ◽  
Central Bureau ◽  
Comparison Star ◽  
Minor Planets ◽  
Julian Date ◽  
Measured Position

In accordance with suggestions made by members of the Commission further consideration of the following topics is proposed:(1)Improvement of the present plan for distribution of observations and computations relating to minor planets and comets, with special reference to those which depart considerably from their ephemerides.(2)Designation of a central bureau to supervise any accepted plan for coordination of observations and computations. It is suggested that separate bureaus be established for Minor Planets and for Comets.(3)Systematic investigations of the orbits of the recently discovered objects designated as minor planets: Reinmuth 1932 HA, and Delporte 1932 EA1( and other objects of similar interest.(4)Financing of proposals (2) and (3).(5)Standard equinoxes as proposed by Comrie (1950.0) and by Bower (1900.0).(6)Designation of published residuals as observed residuals rather than referring to the epoch of the comparison star.(7)Greater adherence to the convention “That the dates used in giving the osculation epochs of elements for comets and minor planets shall be the midnight following an integral Julian date which is exactly divisible by 40, and for ephemerides, divisible by 8 (or 4, etc.),” to facilitate intercomparison of ephemerides and elements.(8)Inauguration of complete residuals of comets, similar to those of minor planets with provision for their continuation.(9)Inclusion in astronomical telegrams of some information of a descriptive nature to indicate the accuracy of the measured position, in confirmation of previous action.(10)Greater emphasis on accurate rather than on approximate positions, particularly in (9), or preliminary orbits.

scholarly journals Photoelectric Observations of AD Leo: 1989-1994

1995 ◽  
Vol 151 ◽  
pp. 87-88
Author(s):  
R. Konstantinova-Antova ◽  
A.P. Antov
Keyword(s):  
Single Channel ◽  
Photon Counting ◽  
Astronomical Observatory ◽  
Program Package ◽  
Flare Star ◽  
The Other ◽  
Integration Time ◽  
Differential Photometry ◽  
Computer Controlled ◽  
Photoelectric Observations

An investigation of the activity of the flare star AD Leo was made using U-band patrol observations. 60 cm computer-controlled telescopes with identical single channel photon-counting photometers at the National Astronomical Observatory at Rozhen and at the Belogradchik Observatory were used. The integration time was 1 sec. Differential photometry was carried out, the AD Leo measurements were made relative to BD+20°2475. The data was reduced with the program package APR (Kirov et al. 1991).Two simultaneous observing runs were made. The results of the first have already been published (Antov etal. 1991). The other was part of the observational campaign in May, 1991 with the ROSAT satellite. In Bulgaria, the observations were carried out at Rozhen in the U-band and at Belogradchik in the B-band. Four flares were detected by both.

scholarly journals The Clover Leaf Quasar H1413+117: New Photometric Light Curves

1996 ◽  
Vol 173 ◽  
pp. 261-262 ◽  
Author(s):  
M. Remy ◽  
E. Gosset ◽  
D. Hutsemékers ◽  
B. Revenaz ◽  
J. Surdej
Keyword(s):  
General Trend ◽  
Light Curves ◽  
The Other ◽  
Comparison Star ◽  
Simultaneous Fitting

Direct CCD images of the gravitationally lensed BAL quasar H1413+117 (Bessel B, V, R, I; Gunn r and i), obtained during 1989-1994 in the framework of photometric monitorings at ESO and with the NOT, have been carefully (re-)analyzed. Simultaneous fitting of 4 PSFs, fixing the relative positions of components B, C and D with respect to A, has been achieved successfully. The relative light curves of the 4 lensed QSO images, with respect to a stable nearby comparison star, confirm the general trend already presented by Arnould et al. (1993). The amplitude of the light curves is found to be about 0.5 magnitude, peak-to-peak in the V filter. The four lensed components display brightness variations quasi-simultaneously and in parallel. In addition to these intrinsic light variations due to the source, we find that component D shows extra light variations with respect to the other components. These are very likely caused by micro-lensing.

scholarly journals A catalogue of Locus Algorithm pointings for optimal differential photometry for 23 779 quasars

2020 ◽  
Vol 498 (3) ◽  
pp. 3720-3729
Author(s):  
Oisín Creaner ◽  
Kevin Nolan ◽  
Niall Smith ◽  
David Grennan ◽  
Eugene Hickey
Keyword(s):  
Time Scale ◽  
Figure Of Merit ◽  
Target Object ◽  
Sloan Digital Sky Survey ◽  
Field Of View ◽  
Computing Paradigm ◽  
Sky Survey ◽  
Differential Photometry ◽  
Suitable Reference

ABSTRACT This paper presents a catalogue of optimized pointings for differential photometry of 23 779 quasars extracted from the Sloan Digital Sky Survey (SDSS) Catalogue and a Score for each indicating the quality of the Field of View (FoV) associated with that pointing. Observation of millimagnitude variability on a time-scale of minutes typically requires differential observations with reference to an ensemble of reference stars. For optimal performance, these reference stars should have similar colour and magnitude to the target quasar. In addition, the greatest quantity and quality of suitable reference stars may be found by using a telescope pointing which offsets the target object from the centre of the FoV. By comparing each quasar with the stars which appear close to it on the sky in the SDSS Catalogue, an optimum pointing can be calculated, and a figure of merit, referred to as the ‘Score’ is calculated for that pointing. Highly flexible software has been developed to enable this process to be automated and implemented in a distributed computing paradigm, which enables the creation of catalogues of pointings given a set of input targets. Applying this technique to a sample of 40 000 targets from the fourth SDSS quasar catalogue resulted in the production of pointings and Scores for 23 779 quasars based on their magnitudes in the SDSS r-band. This catalogue is a useful resource for observers planning differential photometry studies and surveys of quasars to select those which have many suitable celestial neighbours for differential photometry.

scholarly journals Relative astrometry and near-infrared differential photometry of nearby southern orbital binaries with adaptive optics

2013 ◽  
Vol 334 (3) ◽  
pp. 237-250
Author(s):  
P. Lampens ◽  
J.-L. Prieur ◽  
R.W. Argyle ◽  
J. Cuypers
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Differential Photometry
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