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Questions about annual aberration and annual parallax of stars
Dear members,
Please help me to answer the following querries about the above subject. 1. It is known that the major axis of parallatic ellipse and of aberrational ellipse are parallel to the ecliptic and their minor axis of both the ellipse are perpendicular to the ecliptic. I want to know that do the both axis of the both ellipses are coincide in such a way that the centre of the both ellipses is same i.e. do the both ellipses are concentric if not then what are their relative posistions? 2. Do the ratio of major axis and minor axis of both the individual ellipses are same or differ? 3. In nautical astronomy bu B.Krasavtsev, B.Khlyustin published by Mir publisher 1970 edition, on page no. 102- "Due to aberration the image of a star will describe on the celestial sphere an ellipse with dimensions tens of times greater than the ellipse due to parallax and the directions of its axis will be different." How it is possible when the parallax varies for star to star and the major axis of the parallatic ellipse also changes and the major axis of the aberrational ellipse being 20.47 having a constant value then how is it possible that the ratio of the both of the major axis will be always of value 10. I will be oblidged for the answers. Yours' Subhash chand Jain |
#2
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Questions about annual aberration and annual parallax of stars
subhash wrote: Dear members, Please help me to answer the following querries about the above subject. 1. It is known that the major axis of parallatic ellipse and of aberrational ellipse are parallel to the ecliptic and their minor axis of both the ellipse are perpendicular to the ecliptic. I want to know that do the both axis of the both ellipses are coincide in such a way that the centre of the both ellipses is same i.e. do the both ellipses are concentric if not then what are their relative posistions? 2. Do the ratio of major axis and minor axis of both the individual ellipses are same or differ? 3. In nautical astronomy bu B.Krasavtsev, B.Khlyustin published by Mir publisher 1970 edition, on page no. 102- "Due to aberration the image of a star will describe on the celestial sphere an ellipse with dimensions tens of times greater than the ellipse due to parallax and the directions of its axis will be different." How it is possible when the parallax varies for star to star and the major axis of the parallatic ellipse also changes and the major axis of the aberrational ellipse being 20.47 having a constant value then how is it possible that the ratio of the both of the major axis will be always of value 10. I will be oblidged for the answers. For a start the Earth's orbit is nearly circular, only very recently has it been possible to observe non circularity directly on stars. Basically aberration is at right angles to parallax. Parallax is the distance the Earth has moved, aberration is the speed of the Earth. With a more or less circular orbit this is at right angle. Check it out by drawing it. *^ Parallax * * * * * 0 *^ Aberration In the case of an ellipse there is no absolutely straightforward exact answer. The algebra is a little messy although these broad principles apply. |
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Questions about annual aberration and annual parallax of stars
Dear Sir,
Received your valuable explaination of my querries but still I want the further clearification of 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 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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