AAS 204th Meeting, June 2004
Session 7 A Walk Through the HR Diagram
Poster, Monday, May 31, 2004, 9:20am-6:30pm, Ballroom

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[7.22] Four-Color Photometry of Standards and Secondary Standards: Single Channel Observations

A. G. D. Philip (ISO and Union College)

Now that no more observations are being added to my catalog of four-color photometry, corrections have been made by comparing the magnitudes of some of the brighter standard stars from night to night and bringing them to a common zeropoint. The table in the poster paper presents the final, corrected, four-color indices for two sets of stars. The first set contains those standard stars which have been observed ten or more times. The range in the number of observations is from 10 to 139, with an average of 34. The probable errors of the catalog observations for the standard stars are ± 0.003, 0.007, 0.005 and the probable errors relative to the published values of the standards (Crawford & Barnes 1970 AJ 73, 978) are ± 0.002, 0.004, 0.004 in (b-y), c1 and m1, respectively. The second set contains secondary standards. Again the number of observations starts at 10 and runs up to 168 with an average of 41. The probable errors of the observations are ± 0.005, 0.010, 0.008 and the probable errors relative to the stars listed in Hauck & Mermilliod (A&AS 129, 431) are ± 0.003, 0.004, 0.007 in (b-y), c1 and m1. The secondary standards range in magnitude y from 5.09 to 10.82. The stars are well spaced in right ascension in both the northern and southern hemispheres. About a dozen of the secondary standard stars are field horizontal-branch stars. The observations were made over a period of 21 years with 41 runs at KPNO, 24 at CTIO, 3 at Mount Wilson, 2 at Steward Observatory and 1 at ESO. A number of people participated in some of these observations and I would like to acknowledge Donald Hayes, John Drilling, Saul Adelman, Larry Relyea, Linda Tifft Matlock and Pascal Dubois for their help. The observatories listed above a thanked for assigning the observing time. Part of this work was supported by grants from the National Science Foundation.

The author(s) of this abstract have provided an email address for comments about the abstract: agdp@union.edu

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