scholarly journals LONG-TERM PHOTOMETRY WITH SKYNET ROBOTIC TELESCOPE NETWORK

Author(s):  
S. Zola ◽  
V. Kouprianov ◽  
D. E. Reichart ◽  
G. Bhatta ◽  
D. B. Caton

In this paper, we describe the Skynet Robotic Telescope Network, a network of about 2 dozen small optical telescopes spanning four continents. For a prospective user of the network, we provide details on its operation and mention certain caveats potentially affecting observations taken under the control of Skynet software. The actual performance of the network is demonstrated by long-term observations of two blazars: OJ 49 and 3C 279. We show their photometric light curves acquired with a subset of Skynet telescopes in the 2018/19 observing seasons. Preliminary results of the analysis of the variability of these two targets are given, including the quantitative properties of light variations and the periods of possible Quasi Periodic Oscillations (QPOs) found in the seasonal light curves.

1979 ◽  
Vol 46 ◽  
pp. 77-88
Author(s):  
Edward L. Robinson

Three distinct kinds of rapid variations have been detected in the light curves of dwarf novae: rapid flickering, short period coherent oscillations, and quasi-periodic oscillations. The rapid flickering is seen in the light curves of most, if not all, dwarf novae, and is especially apparent during minimum light between eruptions. The flickering has a typical time scale of a few minutes or less and a typical amplitude of about .1 mag. The flickering is completely random and unpredictable; the power spectrum of flickering shows only a slow decrease from low to high frequencies. The observations of U Gem by Warner and Nather (1971) showed conclusively that most of the flickering is produced by variations in the luminosity of the bright spot near the outer edge of the accretion disk around the white dwarf in these close binary systems.


1991 ◽  
Author(s):  
Jeffrey A. Hatch ◽  
David S. Montgomery ◽  
John A. Prior

2013 ◽  
Vol 72 (Suppl 3) ◽  
pp. A736.1-A736
Author(s):  
D. Dimopoulou ◽  
M. Trachana ◽  
P. Sidiropoulos ◽  
P. Tsitsi ◽  
A. Moihovitou ◽  
...  

1998 ◽  
Vol 11 (1) ◽  
pp. 382-382
Author(s):  
Wonyong Han ◽  
Chun-Hwey Kim ◽  
Jae Woo Lee ◽  
Ho-Il Kim ◽  
Woo-Baik Lee

The BVR CCD observations of W UMa-type eclipsing binary SS Arietis were made for ten nights from November 1996 to December 1996 at the Sobaeksan Astronomy Observatory. From the observed light curves, nine new times of minimum lights were derived from the Kwee and van Woerden’s method. Improved light elements for this system were determined from these minimum lights with all the published minima. The analysis of the times of minima of SS Ari confirms that the orbital period of SS Ari has been suffering from a sinusoidal variation as the suggestions of other previous investigators (Kaluzny & Pojmanski 1984, Demircan & Selam 1993). The calculation shows that the cyclic period change has a period of about 56.3yrs with an amplitude of about 0.d052. The period variation has been discussed in terms of two potential mechanisms: 1) the light-time effect due to a hypothetical third body and 2) deformations in the convective envelope of a magnetically active component. The BVR light curves of SS Ari observed for about one month showed the existence of cycle to cycle light variations. Long-term light changes of SS Ari are discussed in terms of the period variation of the binary system.


Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Anna Pazdur ◽  
Mieczysław F. Pazdur ◽  
Jacek Pawlyta ◽  
Andrzej Górny ◽  
Michał Olszewski

We report preliminary results of a long-term systematic study intended to gather paleoclimatic records from precisely dated speleothems. The research project is limited to speleothems deposited in caves of the Cracow-Wieluń Upland, the largest and best-explored karst region in Poland, covering ca. 2900 km2 with >1000 caves. Speleothem samples were selected from collections of the Geological Museum of the Academy of Mining and Metallurgy in Cracow. Radiocarbon dates of these samples from ca. 45–20 ka bp almost exactly coincide with age range of the Interplenivistulian. A break in speleothem formation between ca. 20 and 10 ka bp may be interpreted as a result of serious climatic deterioration associated with the maximum extent of the last glaciation. We observed differences among 14C, U/Th and AAR dating results. Changes of δ13C and δ18O in speleothems that grew between ca. 30 and 20 ka bp may be interpreted as changes of paleoclimatic conditions.


2013 ◽  
Vol 85 (4) ◽  
pp. 190 ◽  
Author(s):  
Konstantinos Stamatiou ◽  
Nikolaos Pierris

Introduction: Chronic prostatitis displays a variety of symptoms (mainly local pain exhibiting variability in origin and intensity). The purpose of this article is to briefly present the preliminary results of our study examining the role of phytotherapeutic agents in the treatment of chronic prostatitis patients. Materials and methods: The study included in total fifty-six consecutive patients who visited the outpatient department. Subjects were randomized into two groups. Subjects in the first group (28 patients) received prulifloxacin 600 mg for 15 days, while subjects in the second group (28 patients) received prulifloxacin 600 mg for 15 days and Serenoa repens extract for 8 weeks. The response was tested using laboratory and clinical criteria. Results: We found statistically significant differences between the two groups regarding pain regression and no statistically significant regarding bacterial eradication. Moreover however while sexual dysfunction improvement was equally achieved in both groups, improvement of urinary symptoms was more evident in the 2nd group especially after the completion of the antibiotic treatment. Conclusions: Serenoa repens extract for 8 weeks seems to improve prostatitis related pain. Further randomized, placebo-controlled studies are needed to substantiate safer conclusions.


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