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Questions about annual aberration and annual parallax of stars
Dear Members,
Please help me to reply the following - The measurement of the major axis of the ellipses formed by stellar aberration and parallax by taking the positional photographs in the observatories of the star under consideration time to time in the duration one year then the major axis are majored of both the ellipses given the value of stellar aberration and parallax respectively. The value of the major axis of aberrational ellipse is 20.47 as a constant for all the stars while the value of the parallax ellipse changes star to star. The maximum value being .772 arc-second for the nearest star Proxima Cen while this value is different for other distant stars. The distances of the stars is calculated as 1/parallax arc-second. Now my problem is the value of major axis for the aberrational ellipse is perfectly constant 20.47 for each star(it is true mathematically but I want to know experimentally) or it varies by slight values if it varies then what is the lower and upper limit of variation. I will be much oblidged for the reply or the suggestion that where can I get the proper detailed answer. With deep regards, S.C. Jain |
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Questions about annual aberration and annual parallax of stars
In article .com,
"subhash" writes: The value of the major axis of aberrational ellipse is 20.47 as a constant That's the value at the ecliptic pole. For other positions, you get a projection of this ellipse. I expect any textbook on astrometry will cover both aberration and parallax in detail. I tried searching "astrometry" and "positional astronomy" at Amazon and got some hits, but it wasn't easy to tell which books are any good, and a lot of them are expensive. Your best bet might be to browse through a university library. Jean Meeus has written several books on practical calculations, but I don't know which if any of them covers precession and aberration in detail. Our library owns _Modern Astrometry_ by Jean Kovalevsky; maybe you could get it on interlibrary loan. Or maybe other posters here will have better recommendations. You might try the link at the bottom of this message, though I don't guarantee it will work. http://www.amazon.com/gp/product/sit...0?ie=UTF8#bort -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
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Questions about annual aberration and annual parallax of stars
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