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Re: Recording The "Brightness" of Comet Lovejoy's Tail

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  • William
    It s funny you should ask that. When McNaught was doing its thing, I put together a ranked list of the Great Comets of the previous two centuries (later
    Message 1 of 22 , Dec 24, 2011
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      It's funny you should ask that. When McNaught was doing its thing, I put together a ranked list of the 'Great Comets' of the previous two centuries (later extended back to AD 1550) by adding together numeric scores for various cometary attributes. The numbers were entirely arbitrary, and if I were to redo the list I would certainly change the scores I awarded certain attributes (the system tends to under-rate the bright sungrazers), but it does yield a relatively impartial list of Great Comets.

      Here is the methodology and ranked list of Great Comets I made at the time, with Lovejoy added with the numbers it had earned as of yesterday (it is likely to increase a few more points before it is done):

      Here is a list I made for my own amusement some time ago, of the greatest naked-eye comets of the last two centuries, visible to observers in the northern temperate regions. I used a points system as follows:

      MAGNITUDE: 10 points for every degree of magnitude brighter than +3 (dark-sky; daytime magnitude gets counted separately)

      TAIL: 1 point for every two degrees of length of naked-eye visible tail in dark sky

      DURATION VISIBLE: 1 point for every month naked-eye visible in dark sky

      BONUS POINTS:
      2 visible tails (dust tail and ion tail) = 10 points
      5 visible "tails" (West 1976) = 20 points
      15 degree long "anti-tail" (Arend-Roland 1957) = 10 points
      curved tail (Donati 1858) = 5 points
      'bright' tail (Daylight 1910) = 10 points
      'brilliant' tail (Ikeya-Seki 1965, Great September 1882) = 20 points
      circumpolar all night (Hyakutake 1996, Tebbutt 1861) = 10 points
      Mag. -3 in daylight (West 1976) or Mag. -5 in daylight (Daylight 1910) = 10 points
      Mag. -8 in daylight (Great March 1843) = 15 points
      Mag. -15 in daylight (Ikeya-Seki 1965) or Mag. -17 in daylight (Great September 1882) = 30 points

      123 pts 1861 Tebbutt
      105 pts 2007 McNaught
      101 pts 1882 Great September Comet
      95 pts 1910 P/Halley
      90 pts 1976 West
      78 pts 1996 Hyakutake
      73 pts 1997 Hale-Bopp
      68 pts 1858 Donati
      64 pts 1965 Ikeya-Seki
      61 pts 1970 Bennett
      57 pts 1957 Arend-Roland
      54 pts 1910 Daylight Comet
      52 pts 1811 Great Comet
      52 pts 2011 Lovejoy
      51 pts 1927 Skjellerup-Maristany
      50 pts 1843 Great March Comet
      46 pts 1874 Coggia
      42 pts 1881 Great Comet
      37 pts 1807 Great Comet
      37 pts 1853 Klinkerfues
      35 pts 1835 P/Halley
      35 pts 1957 Mrkos
      31 pts 1860 Great Comet
      29 pts 1911 Beljawsky
      28 pts 1911 Brooks
      25 pts 1819 Tralles
      24 pts 1854 Great Comet

      Here is the same list in reverse chronological order:

      52 pts 2011 Lovejoy
      105 pts 2007 McNaught
      73 pts 1997 Hale-Bopp
      78 pts 1996 Hyakutake
      90 pts 1976 West
      61 pts 1970 Bennett
      64 pts 1965 Ikeya-Seki
      57 pts 1957 Arend-Roland
      35 pts 1957 Mrkos
      51 pts 1927 Skjellerup-Maristany
      29 pts 1911 Beljawsky
      28 pts 1911 Brooks
      95 pts 1910 P/Halley
      54 pts 1910 Daylight Comet
      101 pts 1882 Great September Comet
      42 pts 1881 Great Comet
      46 pts 1874 Coggia
      123 pts 1861 Tebbutt
      31 pts 1860 Great Comet
      68 pts 1858 Donati
      24 pts 1854 Great Comet
      37 pts 1853 Klinkerfues
      50 pts 1843 Great March Comet
      35 pts 1835 P/Halley
      25 pts 1819 Tralles
      52 pts 1811 Great Comet
      37 pts 1807 Great Comet

      Here is a (partial) list of the most notable Great Comets from the 250 years prior to this list. Details are much sketchier, of course, and for the first portion of this time period we have few or no records from the southern hemisphere, so I expect that the list is incomplete, but the five comets listed are surely among the top Great Comets of that time period. These numbers are a minimum, I do not know if their ion tails were visible -- if so, that's another 10 points.

      1577 (Brahe) : 80 degree tail; magnitude -3 in dark sky; reached magnitude -8 in daylight; visible for 3 months; 'brilliant' tail = 138 points

      1618 : 104 degree tail; magnitude -0.5; visible for 2 months = 89 points

      1680 (Kirch) : 90 degree tail; magnitude 1.5 under dark sky; sungrazer (but not a member of the Kreutz family) visible in daytime (no magnitude estimate -- I am assuming -3); noted for bright tail; visible for 3 months = 83 points

      1744 (Klinkenberg) : 90 degree tail; magnitude -3 under dark-sky(ish) conditions; magnitude -7 daylight comet; 6 "tails" visible; visible for 4 months = 144 points or more

      1769 (Messier) : 97 degree tail; magnitude 0 under dark-sky conditions; magnitude -6 daylight comet; visible for 3 months = 91 points (possibly more, depending on the brightness of the tail)

      Bill

      Edit -- The number of Really Great Comets (80 or more points) in the nineteenth and twentieth centuries is four, giving an average recurrence interval of 50 years, so in 250 years you would expect about 5 comets, if that rate is typical. So there may be another Really Great Comet in the years from 1550 to 1800, most likely from the first half of this time span and only visible in the southern hemisphere, and hence unrecorded -- or there may not.

      The top ten recorded comets of the past 450 years:

      144 pts 1744 Klinkenberg
      138 pts 1577 Brahe
      123 pts 1861 Tebbutt
      105 pts 2007 McNaught
      101 pts 1882 Great September Comet
      95 pts 1910 P/Halley
      91 pts 1769 Messier
      90 pts 1976 West
      89 pts 1618 Great Comet
      83 pts 1680 Kirch

      And in reverse chronological order:

      96 pts 2007 McNaught
      90 pts 1976 West
      95 pts 1910 P/Halley
      101 pts 1882 Great September Comet
      123 pts 1861 Tebbutt
      91 pts 1769 Messier
      144 pts 1744 Klinkenberg
      83 pts 1680 Kirch
      89 pts 1618 Great Comet
      138 pts 1577 Brahe

      --- In comets-ml@yahoogroups.com, dfischer@... wrote:

      > E.g. as a Lovejoy-deprived Northerner I would really like to know how this one 'compares' to Hale-Bopp at its best. Or how McNaught compared to the Greatest Comets in recorded history. The question is thus: Can one compress the overall sight of a comet, coma AND tail, into just one somewhat reliable and reproducible number?

      Dan
    • William
      ... Should be: And in reverse chronological order: 105 pts 2007 McNaught 90 pts 1976 West 95 pts 1910 P/Halley 101 pts 1882 Great September Comet 123 pts 1861
      Message 2 of 22 , Dec 24, 2011
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        --- In comets-ml@yahoogroups.com, "William" <mongo62aa@...> wrote:

        > And in reverse chronological order:
        >
        > 96 pts 2007 McNaught
        > 90 pts 1976 West
        > 95 pts 1910 P/Halley
        > 101 pts 1882 Great September Comet
        > 123 pts 1861 Tebbutt
        > 91 pts 1769 Messier
        > 144 pts 1744 Klinkenberg
        > 83 pts 1680 Kirch
        > 89 pts 1618 Great Comet
        > 138 pts 1577 Brahe

        Should be:

        And in reverse chronological order:

        105 pts 2007 McNaught
        90 pts 1976 West
        95 pts 1910 P/Halley
        101 pts 1882 Great September Comet
        123 pts 1861 Tebbutt
        91 pts 1769 Messier
        144 pts 1744 Klinkenberg
        83 pts 1680 Kirch
        89 pts 1618 Great Comet
        138 pts 1577 Brahe
      • dfischer@astro.uni-bonn.de
        ... Wonderful, and a great list to ponder! For example, how did Hyakutake manage to beat Hale-Bopp? The apparition of the former was much shorter (those who
        Message 3 of 22 , Dec 24, 2011
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          > I put together a ranked list of the 'Great Comets' of the previous
          > two centuries (later extended back to AD 1550) by adding together
          > numeric scores for various cometary attributes.

          Wonderful, and a great list to ponder! For example, how did Hyakutake
          manage to beat Hale-Bopp? The apparition of the former was much shorter
          (those who had a bad weather week missed it completely) and the tail
          (brightness) much lower but the tail length was much larger at the peak
          (going all over the sky for a few days): was the latter aspect the winning
          factor?

          Dan
        • William
          I compiled the list four years ago and do not recall the numbers I used then, but I believe that Hyakutake being circumpolar at its peak had a lot to do with
          Message 4 of 22 , Dec 24, 2011
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            I compiled the list four years ago and do not recall the numbers I used then, but I believe that Hyakutake being circumpolar at its peak had a lot to do with it (ten points right there), not to mention its extraordinary tail length.

            If I were to redo the list, I would probably not put so much emphasis on the length of the tail.

            --- In comets-ml@yahoogroups.com, dfischer@... wrote:
            >
            > > I put together a ranked list of the 'Great Comets' of the previous
            > > two centuries (later extended back to AD 1550) by adding together
            > > numeric scores for various cometary attributes.
            >
            > Wonderful, and a great list to ponder! For example, how did Hyakutake
            > manage to beat Hale-Bopp? The apparition of the former was much shorter
            > (those who had a bad weather week missed it completely) and the tail
            > (brightness) much lower but the tail length was much larger at the peak
            > (going all over the sky for a few days): was the latter aspect the winning
            > factor?
            >
            > Dan
            >
          • William
            One interesting result of this list is to look at clusters of Great Comets. I define a cluster as two or more Great Comets occurring within a span of two
            Message 5 of 22 , Dec 24, 2011
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              One interesting result of this list is to look at "clusters" of Great Comets. I define a cluster as two or more Great Comets occurring within a span of two years.

              1910-11: 4 comets, 206 pts
              1860-61: 2 comets, 154 pts
              1996-97: 2 comets, 151 pts
              1881-82: 2 comets, 143 pts
              1957: 2 comets, 92 pts
              1853-54: 2 comets, 92 pts
            • David Seargent
              Hi John and all, I tried this today (Dec. 24, 1640 UT) using a 25x100 binocular telescope and it actually proved pretty difficult, but more of this in a
              Message 6 of 22 , Dec 24, 2011
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                Hi John and all,
                I tried this today (Dec. 24, 1640 UT) using a 25x100 binocular telescope and it actually proved pretty difficult, but more of this in a moment. First, a general description of the comet this morning. I thought that the tail was somewhat less intense but longer than on the previous 2 mornings and the head (which was very indistinct and essentially just a lower terminus of the tail) about magnitude 4.8. By the way, the 15 degrees I gave as the tail length for Dec. 21 should read 21 degrees. I left out a term in the formula used for calculating angular distances on the sky (OK, math was never my strong point. If it had been, I probably would have studied Physics instead of Philosophy and become a professional astronomer!). In any case, this mornings tail length was measured as 28 degrees.
                As for intensity, retracting the eyepieces right out of the holders to defocus star images sufficiently, I managed the following approximate results;

                4 degrees from head: tail about 0.5 degrees wide and equal to magnitude 4 star
                8 degrees: 1 degree wide and equal to 4.5 star
                23 degrees: 2 degrees wide and equal to mag. 5 star

                All of these values are approximate, but they suggest that (within bounds of error) the tail was roughly the same "total brightness" throughout but with surface intensity falling off as the tail grew wider.
                The length, shape and general morphology of the tail looked very similar to that of Ikeya-Seki when observed the same number of days after perihelion. Yet, I-S was definitely more intense; I would guess from memory about 2 magnitudes brighter. Also, the terminus of the tail seemed to end more suddenly than that of Lovejoy (the last 5 degrees or so of W3's tail grew very faint and difficult with the naked eye and could not be traced in the telescope). But the biggest difference was the head. At this point in its orbit, the head of the earlier comet was also about 2 magnitudes brighter and appeared in the 20x65 binoculars that I was then using as a very distinct, almost disk-like object; rather like a very bright and compact planetary nebula.
                In comparing the two comets, it is also noteworthy to recall that I-S was then on the other side of the Sun, considerably more remote than W3, observed more "end on" than the present comet (with the tail pointing away from us and not toward us as in the present instance) and at a phase angle that deprived it of the forward scattering effect that (although diminishing) must still be contributing to some degree to the brightness of Comet Lovejoy.
                Hope that this proves to be of some use in any comparison between these two comets.
                Warmest wishes for the Christmas season.
                David Seargent



                To: comets-ml@yahoogroups.com
                From: jbortle@...
                Date: Sat, 24 Dec 2011 03:58:26 +0000
                Subject: [comets-ml] Recording The "Brightness" of Comet Lovejoy's Tail







                Might I suggest that a few of the more experienced southern comet observers attempt to ascertain an approximate magnitude for various parts of the comet's tail. I did this back in 1965 for Ikeya-Seki and it would certainly be interesting to see just how these measures compare to Lovejoy's.

                My points of measurement were roughly at (1) 3-5 degrees behind the coma, (2) near the mid-point of the tail, (3) about 3 degrees from the visual end of the tail. Binoculars were used for these observations. In each case comparison stars of known brightness were expanded through defocusing the binoculars until the sized of the extrafocal star images matched the tail's width at the given locations. Also record the width of the tail at the point of measurement. Such observations will offer some indication of the surface brightness of the tail, allowing future observers some impression of just how bright the tails of comets Ikeya-Seki and Lovejoy were to visual observers.

                J.Bortle






                [Non-text portions of this message have been removed]
              • terryjlovejoy
                Hi John, I ve been mostly clouded or rained out for the post perihelion phase of the comet but did manage to view and image the comet under excellent
                Message 7 of 22 , Dec 24, 2011
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                  Hi John,

                  I've been mostly clouded or rained out for the post perihelion phase of the comet but did manage to view and image the comet under excellent conditions on Dec 23.73 UT. On that morning I could easily trace the tail to 20 degrees with the naked eye and trace it to 22 degrees in wide angle digital SLR images. From a larger scale digital image I measured the mid point (i.e 10 degree point) of the primary tail as equal to the brightness of a mag 3.6 star defocused to the width of the tail (0.6 degrees). The coma itself was estimated at just mag 5.1 also using digital images and a measuring apeture of 10' (and visually it required 7x50 binoculars to see the form of the coma).

                  If I normalise these surface brightness measurements into stars defocused to 1 degree diameter the following values are calculated:

                  Coma : mag 1.2 p circular/deg
                  tail (10 degrees from coma) : mag 2.5 p/circular deg

                  For these measurement the 3 circle aperture tool in IRIS and the Tycho Vt magnitudes were used. Care was taken to use comparision stars at the same altitude.

                  As it so happens I have comparible images for C/2006P1 taken on January 20, 2007, using the same camera. At 10 degrees above the coma, the surface brightness was estimated at conservatively mag 1.0 p/circular deg! Individual striations were even brighter. This confirms the impression that this comet was considerably more impressive than W3. Having said that who could have anticipated that a faint mag 13 comet discovered just 4 weeks ago could have turned into a very fine naked eye object!

                  I actually think these sort of measurements could be useful in calculation of mass release versus time. I also hope this helps put W3 into some historical context.

                  Terry
                • David Nicholls
                  ... It s probably not very useful to rank comets that appeared at their best in the opposite hemisphere. e.g. Hale-Bopp was nothing special when it finally
                  Message 8 of 22 , Dec 25, 2011
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                    On 25/12/2011, at 1:41 AM, dfischer@...-bonn.de wrote:

                    >> I put together a ranked list of the 'Great Comets' of the previous
                    >> two centuries (later extended back to AD 1550) by adding together
                    >> numeric scores for various cometary attributes.
                    >

                    It's probably not very useful to rank comets that appeared at their best in the opposite hemisphere. e.g. Hale-Bopp was nothing special when it finally moved south - easy naked eye but not in the least spectacular. Likewise Hyakutake, which, as mentioned, was circumpolar in the north, was effectively invisible in the south. Also, numerical attributes are inevitably arbitrary choices.

                    Of the comets I have seen at their best, my ranking (on a completely arbitrary basis) would be:

                    1. Ikeya-Seki (well out in front, an "oh! wow!" comet)
                    2. McNaught (clear second, and pretty special - you could see it in the sky through your car window while driving around suburban streets at night)
                    =3. Lovejoy (not bright but long)
                    =3. Bennett (when I was living in Canada)
                    =4. (Hale-Bopp when visible in the south)
                    =4. Halley

                    I missed West and Hyakutake was a binocular object in the south.

                    My rankings are based on the "visual impact" of the object (apparent brightness and size), and are, as I said, entirely arbitrary.

                    DN
                    Canberra
                  • Paul Floyd
                    David, I had quite a different experience of Hyakutake - living in the Gold Coast Hinterland. My daughter was born the day the comet was discovered and was
                    Message 9 of 22 , Dec 25, 2011
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                      David,

                      I had quite a different experience of Hyakutake - living in the Gold Coast
                      Hinterland.

                      My daughter was born the day the comet was discovered and was therefore was
                      quite young (a baby) when it swept by the Earth. I followed it closely (a
                      tiny fuzzy blob) through to being the last morning it was visible from the
                      Gold Coast Hinterland - before the curvature of the Earth got in the way
                      (literally). I didn't plan to get up early on the last morning it would be
                      visible from my location as I figured there would be no point - the nucleus
                      being located almost on the horizon.

                      My partner had to get up early that morning to feed my daughter and came in
                      and woke me up. She simply said that I should go outside and look at
                      Hyakutake. I went outside and my jaw dropped. The tail was 45 degrees long
                      and I could see the nucleus visible just above the Northern horizon.
                      Apparently the tail was even longer over the next few nights from locations
                      in the Northern hemisphere.

                      As an aside, my (almost) 16 year old was given a picture of Hyakutake as a
                      birthday present when she was about 9 (?). As far as I know she still
                      treasures it.

                      Regards,

                      Paul Floyd.



                      On Sun, Dec 25, 2011 at 7:18 PM, David Nicholls <dcn@...> wrote:

                      > **
                      >
                      >
                      >
                      > On 25/12/2011, at 1:41 AM, dfischer@...-bonn.de wrote:
                      >
                      > I missed West and Hyakutake was a binocular object in the south.
                      >
                      > My rankings are based on the "visual impact" of the object (apparent
                      > brightness and size), and are, as I said, entirely arbitrary.
                      >
                      > DN
                      > Canberra
                      >
                      >


                      [Non-text portions of this message have been removed]
                    • David Nicholls
                      Interesting. Canberra is 7 degrees further south than the Gold Coast, so I didn t go looking for it. DN
                      Message 10 of 22 , Dec 25, 2011
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                        Interesting. Canberra is 7 degrees further south than the Gold Coast, so I didn't go looking for it.

                        DN

                        On 25/12/2011, at 7:50 PM, Paul Floyd wrote:

                        > David,
                        >
                        > I had quite a different experience of Hyakutake - living in the Gold Coast
                        > Hinterland.
                        >
                        > My daughter was born the day the comet was discovered and was therefore was
                        > quite young (a baby) when it swept by the Earth. I followed it closely (a
                        > tiny fuzzy blob) through to being the last morning it was visible from the
                        > Gold Coast Hinterland - before the curvature of the Earth got in the way
                        > (literally). I didn't plan to get up early on the last morning it would be
                        > visible from my location as I figured there would be no point - the nucleus
                        > being located almost on the horizon.
                        >
                        > My partner had to get up early that morning to feed my daughter and came in
                        > and woke me up. She simply said that I should go outside and look at
                        > Hyakutake. I went outside and my jaw dropped. The tail was 45 degrees long
                        > and I could see the nucleus visible just above the Northern horizon.
                        > Apparently the tail was even longer over the next few nights from locations
                        > in the Northern hemisphere.
                        >
                        > As an aside, my (almost) 16 year old was given a picture of Hyakutake as a
                        > birthday present when she was about 9 (?). As far as I know she still
                        > treasures it.
                        >
                        > Regards,
                        >
                        > Paul Floyd.
                        >
                        >
                        >
                        > On Sun, Dec 25, 2011 at 7:18 PM, David Nicholls <dcn@...> wrote:
                        >
                        >> **
                        >>
                        >>
                        >>
                        >> On 25/12/2011, at 1:41 AM, dfischer@...-bonn.de wrote:
                        >>
                        >> I missed West and Hyakutake was a binocular object in the south.
                        >>
                        >> My rankings are based on the "visual impact" of the object (apparent
                        >> brightness and size), and are, as I said, entirely arbitrary.
                        >>
                        >> DN
                        >> Canberra
                        >>
                        >>
                        >
                        >
                        > [Non-text portions of this message have been removed]
                        >
                        >
                        >
                        > ------------------------------------
                        >
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                      • Paul Floyd
                        David, It was an interesting lesson for me regarding the benefit that a comet being close to the Earth. From memory, the (estimated size) nucleus of Hyakutake
                        Message 11 of 22 , Dec 25, 2011
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                          David,

                          It was an interesting lesson for me regarding the benefit that a comet
                          being close to the Earth. From memory, the (estimated size) nucleus of
                          Hyakutake wasn't that big. It was impressive because it was close.

                          Regards,

                          Paul Floyd.





                          On Sun, Dec 25, 2011 at 8:24 PM, David Nicholls <dcn@...> wrote:

                          > **
                          >
                          >
                          > Interesting. Canberra is 7 degrees further south than the Gold Coast, so I
                          > didn't go looking for it.
                          >
                          > DN
                          >
                          >
                          > On 25/12/2011, at 7:50 PM, Paul Floyd wrote:
                          >
                          > > David,
                          > >
                          > > I had quite a different experience of Hyakutake - living in the Gold
                          > Coast
                          > > Hinterland.
                          > >
                          > > My daughter was born the day the comet was discovered and was therefore
                          > was
                          > > quite young (a baby) when it swept by the Earth. I followed it closely (a
                          > > tiny fuzzy blob) through to being the last morning it was visible from
                          > the
                          > > Gold Coast Hinterland - before the curvature of the Earth got in the way
                          > > (literally). I didn't plan to get up early on the last morning it would
                          > be
                          > > visible from my location as I figured there would be no point - the
                          > nucleus
                          > > being located almost on the horizon.
                          > >
                          > > My partner had to get up early that morning to feed my daughter and came
                          > in
                          > > and woke me up. She simply said that I should go outside and look at
                          > > Hyakutake. I went outside and my jaw dropped. The tail was 45 degrees
                          > long
                          > > and I could see the nucleus visible just above the Northern horizon.
                          > > Apparently the tail was even longer over the next few nights from
                          > locations
                          > > in the Northern hemisphere.
                          > >
                          > > As an aside, my (almost) 16 year old was given a picture of Hyakutake as
                          > a
                          > > birthday present when she was about 9 (?). As far as I know she still
                          > > treasures it.
                          > >
                          > > Regards,
                          > >
                          > > Paul Floyd.
                          > >
                          > >
                          > >
                          > > On Sun, Dec 25, 2011 at 7:18 PM, David Nicholls <dcn@...>
                          > wrote:
                          > >
                          > >> **
                          >
                          >


                          [Non-text portions of this message have been removed]
                        • Ervin Fleming
                          My first great comet was Bennett (you always remember your first). I took some family members out of town before dawn heading west. Turned north on a country
                          Message 12 of 22 , Dec 25, 2011
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                            My first great comet was Bennett (you always remember your first). I took some
                            family members out of town before dawn heading west. Turned north on a country
                            road and pointed east while keeping my eye on the road. I said, "You should see
                            it over there." At that moment, I picked up the comet with peripheral vision,
                            looked and said "Oh my God!", veered off the road and stopped to set up my
                            camera. In April, I logged a 45 degree tail in binoculars.
                            But for me "West is the best" (Jim Morrison lyric).  Most certainly would have
                            ranked McNaught ahead but I reside in the northern hemisphere. West was
                            spectacular and had a lot in common with McNaught.
                            Tom Fleming   

                             



                            ________________________________
                            From: Paul Floyd <p.n.floyd@...>
                            To: comets-ml@yahoogroups.com
                            Sent: Sun, December 25, 2011 3:30:42 AM
                            Subject: Re: [comets-ml] Ranking Great Comets, was Re: Recording The
                            "Brightness" of Comet Lovejoy's Tail

                             
                            David,

                            It was an interesting lesson for me regarding the benefit that a comet
                            being close to the Earth. From memory, the (estimated size) nucleus of
                            Hyakutake wasn't that big. It was impressive because it was close.

                            Regards,

                            Paul Floyd.

                            On Sun, Dec 25, 2011 at 8:24 PM, David Nicholls <dcn@...> wrote:

                            > **
                            >
                            >
                            > Interesting. Canberra is 7 degrees further south than the Gold Coast, so I
                            > didn't go looking for it.
                            >
                            > DN
                            >
                            >
                            > On 25/12/2011, at 7:50 PM, Paul Floyd wrote:
                            >
                            > > David,
                            > >
                            > > I had quite a different experience of Hyakutake - living in the Gold
                            > Coast
                            > > Hinterland.
                            > >
                            > > My daughter was born the day the comet was discovered and was therefore
                            > was
                            > > quite young (a baby) when it swept by the Earth. I followed it closely (a
                            > > tiny fuzzy blob) through to being the last morning it was visible from
                            > the
                            > > Gold Coast Hinterland - before the curvature of the Earth got in the way
                            > > (literally). I didn't plan to get up early on the last morning it would
                            > be
                            > > visible from my location as I figured there would be no point - the
                            > nucleus
                            > > being located almost on the horizon.
                            > >
                            > > My partner had to get up early that morning to feed my daughter and came
                            > in
                            > > and woke me up. She simply said that I should go outside and look at
                            > > Hyakutake. I went outside and my jaw dropped. The tail was 45 degrees
                            > long
                            > > and I could see the nucleus visible just above the Northern horizon.
                            > > Apparently the tail was even longer over the next few nights from
                            > locations
                            > > in the Northern hemisphere.
                            > >
                            > > As an aside, my (almost) 16 year old was given a picture of Hyakutake as
                            > a
                            > > birthday present when she was about 9 (?). As far as I know she still
                            > > treasures it.
                            > >
                            > > Regards,
                            > >
                            > > Paul Floyd.
                            > >
                            > >
                            > >
                            > > On Sun, Dec 25, 2011 at 7:18 PM, David Nicholls <dcn@...>
                            > wrote:
                            > >
                            > >> **
                            >
                            >

                            [Non-text portions of this message have been removed]




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                          • Frans van Loo
                            Tom, I agree your exp. My first attemt was Ikeya -Seki, but failed due my 51 degree North position. Bennett became my first photograped comet and West was
                            Message 13 of 22 , Dec 25, 2011
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                              Tom,

                              I agree your exp.
                              My first attemt was Ikeya -Seki, but failed due my 51 degree North position.
                              Bennett became my first photograped comet and West was great!
                              The rest wil be similar like others , Hale Bob and Hyakutake etc..
                              Thanks internet , the southern comets as McNaught ( a daylight observation for me ! ) and Lovejoy s comet ,, the emotions reach further than the equator !!

                              However, some comets maybe became not so trilling but ,at least , more or less valuable for the science of comets , Kohoutek for example..

                              Merry Christmas to all.

                              Frans van Loo.
                              Genk B.


                              ----- Original Message -----
                              From: Ervin Fleming
                              To: comets-ml@yahoogroups.com
                              Sent: Sunday, December 25, 2011 12:14 PM
                              Subject: Re: [comets-ml] Ranking Great Comets, was Re: Recording The "Brightness" of Comet Lovejoy's Tail



                              My first great comet was Bennett (you always remember your first). I took some
                              family members out of town before dawn heading west. Turned north on a country
                              road and pointed east while keeping my eye on the road. I said, "You should see
                              it over there." At that moment, I picked up the comet with peripheral vision,
                              looked and said "Oh my God!", veered off the road and stopped to set up my
                              camera. In April, I logged a 45 degree tail in binoculars.
                              But for me "West is the best" (Jim Morrison lyric). Most certainly would have
                              ranked McNaught ahead but I reside in the northern hemisphere. West was
                              spectacular and had a lot in common with McNaught.
                              Tom Fleming



                              ________________________________
                              From: Paul Floyd <p.n.floyd@...>
                              To: comets-ml@yahoogroups.com
                              Sent: Sun, December 25, 2011 3:30:42 AM
                              Subject: Re: [comets-ml] Ranking Great Comets, was Re: Recording The
                              "Brightness" of Comet Lovejoy's Tail


                              David,

                              It was an interesting lesson for me regarding the benefit that a comet
                              being close to the Earth. From memory, the (estimated size) nucleus of
                              Hyakutake wasn't that big. It was impressive because it was close.

                              Regards,

                              Paul Floyd.

                              On Sun, Dec 25, 2011 at 8:24 PM, David Nicholls <dcn@...> wrote:

                              > **
                              >
                              >
                              > Interesting. Canberra is 7 degrees further south than the Gold Coast, so I
                              > didn't go looking for it.
                              >
                              > DN
                              >
                              >
                              > On 25/12/2011, at 7:50 PM, Paul Floyd wrote:
                              >
                              > > David,
                              > >
                              > > I had quite a different experience of Hyakutake - living in the Gold
                              > Coast
                              > > Hinterland.
                              > >
                              > > My daughter was born the day the comet was discovered and was therefore
                              > was
                              > > quite young (a baby) when it swept by the Earth. I followed it closely (a
                              > > tiny fuzzy blob) through to being the last morning it was visible from
                              > the
                              > > Gold Coast Hinterland - before the curvature of the Earth got in the way
                              > > (literally). I didn't plan to get up early on the last morning it would
                              > be
                              > > visible from my location as I figured there would be no point - the
                              > nucleus
                              > > being located almost on the horizon.
                              > >
                              > > My partner had to get up early that morning to feed my daughter and came
                              > in
                              > > and woke me up. She simply said that I should go outside and look at
                              > > Hyakutake. I went outside and my jaw dropped. The tail was 45 degrees
                              > long
                              > > and I could see the nucleus visible just above the Northern horizon.
                              > > Apparently the tail was even longer over the next few nights from
                              > locations
                              > > in the Northern hemisphere.
                              > >
                              > > As an aside, my (almost) 16 year old was given a picture of Hyakutake as
                              > a
                              > > birthday present when she was about 9 (?). As far as I know she still
                              > > treasures it.
                              > >
                              > > Regards,
                              > >
                              > > Paul Floyd.
                              > >
                              > >
                              > >
                              > > On Sun, Dec 25, 2011 at 7:18 PM, David Nicholls <dcn@...>
                              > wrote:
                              > >
                              > >> **
                              >
                              >

                              [Non-text portions of this message have been removed]

                              [Non-text portions of this message have been removed]





                              [Non-text portions of this message have been removed]
                            • JS&EJ Gifford
                              David, Paul and All, My experience with Hyakutake was the same as Pauls but my location in Bridgetown at 34degrees south is similar to Davids. After following
                              Message 14 of 22 , Dec 25, 2011
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                                David, Paul and All,
                                My experience with Hyakutake was the same as Pauls but my location in Bridgetown at 34degrees south is similar to Davids. After following the smudge for weeks along the eastern horizon we were rained off and the computer was telling me that it was no longer visible that far south, and without the tail that may have been so, but on waking at midnight I went out for a last look and was amazed at what the smudge had turned into stretched across the sky. Never assume this or that will happen with a comet until it actually has, for me that uncertainty is one of the great joys of following comets.
                                regards, Jim Gifford.

                                ----- Original Message -----
                                From: David Nicholls
                                To: comets-ml@yahoogroups.com
                                Sent: Sunday, December 25, 2011 5:24 PM
                                Subject: Re: [comets-ml] Ranking Great Comets, was Re: Recording The "Brightness" of Comet Lovejoy's Tail



                                Interesting. Canberra is 7 degrees further south than the Gold Coast, so I didn't go looking for it.

                                DN




                                [Non-text portions of this message have been removed]
                              • Rodney Austin
                                My impression of Hyakutake was set by observing it from Norfolk Island; only one streetlight on the island (!). Tail length was the thing with that one. The
                                Message 15 of 22 , Dec 25, 2011
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                                  My impression of Hyakutake was set by observing it from Norfolk Island;
                                  only one streetlight on the island (!). Tail length was the thing with that
                                  one. The sungrazers Ikeya-Seki, White-Orti-Bolleli and now Lovejoy are
                                  truly fascinating, but Hale-Bopp was just a great brute of a comet. It
                                  picked you up like a ragdoll and shook you until your teeth rattled - not
                                  pretty but a hammer blow of an object. McNaught was by far the most
                                  beautiful. All very subjective and not remotely scientific.
                                  Cheers
                                  Rod


                                  [Non-text portions of this message have been removed]
                                • David Nicholls
                                  Curious Ikeya Seki at No. 3, but that s what personal impressions are about. The point I think one can draw from all of these is that Lovejoy is in the list
                                  Message 16 of 22 , Dec 25, 2011
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                                    Curious Ikeya Seki at No. 3, but that's what personal impressions are about. The point I think one can draw from all of these is that Lovejoy is in the list of "Great Comets". So As David S put it, we should call it "The Great Christmas Comet of 2011". Has a nice ring to it :-)

                                    DN

                                    On 26/12/2011, at 3:40 PM, Rodney Austin wrote:

                                    > My impression of Hyakutake was set by observing it from Norfolk Island;
                                    > only one streetlight on the island (!). Tail length was the thing with that
                                    > one. The sungrazers Ikeya-Seki, White-Orti-Bolleli and now Lovejoy are
                                    > truly fascinating, but Hale-Bopp was just a great brute of a comet. It
                                    > picked you up like a ragdoll and shook you until your teeth rattled - not
                                    > pretty but a hammer blow of an object. McNaught was by far the most
                                    > beautiful. All very subjective and not remotely scientific.
                                    > Cheers
                                    > Rod
                                    >
                                  • perryhelion
                                    My great comet experiences: Halley - Ok. Faint naked eye. Nice in binoculars. Similar in appearance to Ikeka-Zhang. Was still glad to see the famous comet.
                                    Message 17 of 22 , Dec 25, 2011
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                                      My 'great' comet experiences:

                                      Halley - Ok. Faint naked eye. Nice in binoculars. Similar in appearance to Ikeka-Zhang. Was still glad to see the famous comet.

                                      Hyakutake - My favorite comet. Photos don't do it justice. I was amazed as the comet grew larger each sucessive night. It was nothing short of awesome when at its closest. It reminded me of a recessed spotlight in a darkened theater.

                                      Hale-Bopp - Second favorite. With the naked eye, it was a nice little blow torch. Binoculars and telescopes revealed some amazing structure, especially the spiral hoods in the coma.

                                      McNaught - Third favorite. I was stuck in the northern hemisphere, but it was really nice even in the bright twilight. I was most disappointed when the sky was clouded over on perihelion day.

                                      An honorable-mention favorite 'great' comet is 17P/Holmes.



                                      --- In comets-ml@yahoogroups.com, David Nicholls <dcn@...> wrote:
                                      >
                                      >
                                      > On 25/12/2011, at 1:41 AM, dfischer@... wrote:
                                      >
                                      > >> I put together a ranked list of the 'Great Comets' of the previous
                                      > >> two centuries (later extended back to AD 1550) by adding together
                                      > >> numeric scores for various cometary attributes.
                                      > >
                                      >
                                      > It's probably not very useful to rank comets that appeared at their best in the opposite hemisphere. e.g. Hale-Bopp was nothing special when it finally moved south - easy naked eye but not in the least spectacular. Likewise Hyakutake, which, as mentioned, was circumpolar in the north, was effectively invisible in the south. Also, numerical attributes are inevitably arbitrary choices.
                                      >
                                      > Of the comets I have seen at their best, my ranking (on a completely arbitrary basis) would be:
                                      >
                                      > 1. Ikeya-Seki (well out in front, an "oh! wow!" comet)
                                      > 2. McNaught (clear second, and pretty special - you could see it in the sky through your car window while driving around suburban streets at night)
                                      > =3. Lovejoy (not bright but long)
                                      > =3. Bennett (when I was living in Canada)
                                      > =4. (Hale-Bopp when visible in the south)
                                      > =4. Halley
                                      >
                                      > I missed West and Hyakutake was a binocular object in the south.
                                      >
                                      > My rankings are based on the "visual impact" of the object (apparent brightness and size), and are, as I said, entirely arbitrary.
                                      >
                                      > DN
                                      > Canberra
                                      >
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