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Re: [comets-ml] Re: C/2006 P1 (McNaught)

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  • Robert McNaught
    ... The outer coma is indeed very diffuse, but there is a very strong central condensation with FWHM 5 .5
    Message 1 of 8 , Oct 1, 2006
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      On Sun, 1 Oct 2006, Michael Mattiazzo wrote:

      > However it appeared highly diffuse which is not a good sign.

      The outer coma is indeed very diffuse, but there is a very strong central
      condensation with FWHM 5".5
    • walcom77
      Dears all, We would like to comment about the results of our observations of C/2006 P1 (McNaught), obtained remotely (near Melbourne, Australia). On 2007, Jan.
      Message 2 of 8 , Jan 26, 2007
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        Dears all,

        We would like to comment about the results of our observations of
        C/2006 P1 (McNaught), obtained remotely (near Melbourne, Australia).

        On 2007, Jan. 23.43, 25.44 and 26.43 we imaged this comet through a
        0.32m, f/9 Ritchey-Chretien reflector + CCD + Red filter (pixel scale
        1.3 "/px, FWHM of the field stars almost 2.5"). We detected the
        presence of three concentric parabolic shells on the sunward side of
        the inner coma (their brightness decreases significantly from the
        innermost to the outermost). We measured their offsets from the
        central condensation as: 7", 17" and 27" +/- 3", respectively.
        An image is available here:

        http://tinyurl.com/yrn2p2


        Images obtained on 2007, Jan 24.44 by A. Rosner through a 0.09m, f/4.6
        refractor + CCD, reveals the presence of a real antitail, placed
        inside (sunward) of the comet orbit, whose lenght (perpendicular to
        the line of sight) has been estimated to be almost 1.61 Million Km;
        assuming that its grains has been emitted at perihelion, their average
        speed turns out to be about 1.6 Km/sec. This feature is striking
        similar to that observed on C/1962 C1 (Seki-Lines) in April 1962. An
        image of this feature is available here:

        http://tinyurl.com/22pby7


        For comparison, this is an archive image of comet Seki-Lines, where
        a similar strucure is readily visible:

        http://tinyurl.com/2767ec


        Cheers,
        G. Sostero, E. Guido (Remanzacco Obs., CARA)

        http://www.afamweb.com
        http://cara.uai.it
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