CCD Photometry of Standard Stars at Maidanak Astronomical Observatory in Uzbekstan: Transformations and Comparisons

Details CCD Photometry of Standard Stars at Maidanak Astronomical Observatory in Uzbekstan: Transformations and Comparisons CCD Photometry of Standard Stars at Maidanak Astronomical Observatory in Uzbekstan: Transformations and Comparisons

2009-09-25

arxiv.org/abs/0909.4587v1

Astronomy and Astrophysics

Astrophysics

Solar and Stellar Astrophysics

14 pages, 13 figures

Scientific paper

Observation of standard stars is of crucial importance in stellar photometry. We have studied the standard transformation relations of the UBVRI CCD photometric system at the Maidanak Astronomical Observatory in Uzbekistan. All observations were made with the AZT-22 1.5m telescope, SITe 2k CCD or Fairchild 486 CCD, and standard Bessell UBVRI filters from 2003 August to 2007 September. We observed many standard stars around the celestial equator observed by SAAO astronomers. The atmospheric extinction coefficients, photometric zero points, and time variation of photometric zero points of each night were determined. Secondary extinction coefficients and photometric zero points were very stable, while primary extinction coefficients showed a distinct seasonal variation. We also determined the transformation coefficients for each filter. For B, V, R, and I filters, the transformation to the SAAO standard system could be achieved with a straight line or a combination of two straight lines. However, in the case of the U filter and Fairchild 486 CCD combination, a significant non-linear correction term - related to the size of Balmer jump or the strength of the Balmer lines - of up to 0.08 mags was required. We found that our data matched well the SAAO photometry in V, B-V, V-I, and R-I. But in U-B, the difference in zero point was about 3.6 mmag and the scatter was about 0.02 mag. We attribute the relatively large scatter in U-B to the larger error in U of the SAAO photometry. We confirm the mostly small differences between the SAAO standard UBVRI system and the Landolt standard system. We also attempted to interpret the seasonal variation of the atmospheric extinction coefficients in the context of scattering sources in the earth's atmosphere.

Affiliated with

Also associated with

No associations

Rating

CCD Photometry of Standard Stars at Maidanak Astronomical Observatory in Uzbekstan: Transformations and Comparisons does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with CCD Photometry of Standard Stars at Maidanak Astronomical Observatory in Uzbekstan: Transformations and Comparisons, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and CCD Photometry of Standard Stars at Maidanak Astronomical Observatory in Uzbekstan: Transformations and Comparisons will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-325246