Measurements of the Solar Radius in Antalya between 2001–2003

Kılıç, Hüseyin Selçuk; Golbasi, O.; Chollet, F.

doi:10.1007/s11207-005-4999-1

Cited by 13 publications

(16 citation statements)

References 27 publications

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“…Specific details of these results have been presented by Delmas et al (2003b), Kiliç et al (2003) and Penna et al (2003). It is worth mentioning here that the sufficiently long standing use of the method and algorithms, both at the same and at different stations, ensures that the features here examined and previously not present cannot be ascribed to defects of the program routines.…”

Section: Introductionmentioning

confidence: 84%

Comparison of CCD astrolabe multi-site solar diameter observations

Andrei¹,

Boscardin

Chollet

et al. 2004

A&A

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Abstract.Results are presented of measured variations of the photospheric solar diameter, as concurrently observed at three sites of the R2S3 (Réseau de Suivi au Sol du Rayon Solaire) consortium in 2001. Important solar flux variations appeared in that year, just after the maximum of solar activity cycle 23, make that time stretch particularly promising for a comparison of the multi-site results. The sites are those in Turkey, France and Brasil. All observations are made with similar CCD solar astrolabes, and at nearby effective wavelengths. The data reductions share algorithms, that are alike, the outcomes of which are here treated after applying a normalization correction using the Fried parameter. Since the sites are geographically quite far, atmospheric conditions are dismissed as possible causes of the large common trend found. Owing to particularities of each site, the common continuous observational period extends from April to September. The standard deviation for the daily averages is close to 0. 47 for the three sites. Accordingly, the three series are smoothed by a low-pass-band Fourier filter of 150 observations (typically one month). The main common features found are a declining linear trend, of the order of 0.7 mas/day, and a relative maximum, around MJD 2120, of the order of 100 mas. Standard statistical tests endorse the correlation of the three series.

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Section: Introductionmentioning

confidence: 84%

Comparison of CCD astrolabe multi-site solar diameter observations

Andrei¹,

Boscardin

Chollet

et al. 2004

A&A

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“…The time series corresponding to a set of more than 3700 independent and homogeneous values was recorded with a CCD video camera at the three zenit distances under different atmospheric conditions. The previous studies indicated that a linear decrease of the observed solar diameter with the atmospheric turbulence effect is present (Irbah et al 1994;Sinceac 1998;Sinceac et al 1998;Chollet & Sinceac 1999; Kiliç, Golbasi & Chollet 2005). To correct this effect causing important errors on solar radius measurements, and to obtain more homogeneous values for the solar radius, we have used a method improved by Sinceac (1998) and (Chollet & Sinceac 1999).…”

Section: Observationsmentioning

confidence: 99%

“…Thus, the data of each year are corrected independently for this effect by reducing all diameter measurements to 1/r 0 (Kiliç, Golbasi & Chollet 2005). The yearly mean values of the CSD obtained in this way and other parameters are given in Table 1.…”

Section: Observationsmentioning

confidence: 99%

Intermediate‐term variations in solar radius during solar cycle 23

Kılıç¹,

Golbasi

Chollet

2009

Astron Nachr

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In this study, we look for the mid-term variations in the daily average data of solar radius measurements made at the Solar Astrolabe Station of TUBITAK National Observatory (TUG) during solar cycle 23 for a time interval from 2000 February 26 to 2006 November 15. Due to the weather conditions and seasonal effect dependent on the latitude, the data series has the temporal gaps. For spectral analysis of the data series, thus, we use the Date Compensated Discrete Fourier Transform (DCDFT) and the CLEANest algorithm, which are powerful methods for irregularly spaced data. The CLEANest spectra of the solar radius data exhibit several significant mid-term periodicities at 393.2, 338.9, 206.5, 195.2, 172.3 and 125.4 days which are consistent with periods detected in several solar time series by several authors during different solar cycles. The knowledge relating to the origin of solar radius variations is not yet present. To see whether these variations will repeat in next cycles and to understand how the amplitudes of such variations change with different phases of the solar cycles, we need more systematic efforts and the long-term homogeneous data. Since most of the periodicities detected in the present study are frequently seen in solar activity indicators, it is thought that the physical mechanisms driving the periodicities of solar activity may also be effective in solar radius variations.

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“…One of these widely used instruments is the solar astrolabe. The description of the visual and CCD generation of this instrument and the results obtained for the diameter of the Sun are given by Laclare et al (1991Laclare et al ( , 1996Laclare et al ( , 1999, Delmas et al (2006), Andrei et al (2004), Gölbaşi et al (2000Gölbaşi et al ( , 2001, Jilinski et al (1999), Penna et al (2002), and Kilic et al (2005).…”

Section: Introductionmentioning

confidence: 99%

“…To show this, we compare three filtering methods using the CCD solar astrolabe data, i.e., the proposed method (see Djafer et al 2008b) based on the compact wavelet that automatically determines the amplitude of the noise present in the image and eliminate it without changing the inflection point position, the FFTD method (see Sofia et al 1983Sofia et al , 1994Egidi et al 2006), and the method actually used with the CCD solar astrolabe (see Sinceac et al 1998;Jilinski et al 1999;Kilic et al 2005). …”

Section: Introductionmentioning

confidence: 99%

Processing Method Effect on Sun Diameter Measurement With CCD Solar Astrolabe

Djafer

Irbah

2012

ApJ

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Photometric Sun diameter measurement is based on the calculation of the inflection point of the solar limb. In ground measurement, this point is located at a position on the solar limb where the signal-to-noise ratio is very high, which necessitates the appropriate filtering techniques to eliminate the noise while preserving its position. In this paper, we compare the filtering method currently in use to process the CCD solar astrolabe data, the FFTD method widely used, with a different method that we propose. Using the acquired data from the CCD astrolabe at Calern, France during 1997, we can obtain a mean difference of 130 mas in the measured radii.

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Measurements of the Solar Radius in Antalya between 2001–2003

Cited by 13 publications

References 27 publications

Comparison of CCD astrolabe multi-site solar diameter observations

Comparison of CCD astrolabe multi-site solar diameter observations

Intermediate‐term variations in solar radius during solar cycle 23

Processing Method Effect on Sun Diameter Measurement With CCD Solar Astrolabe

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