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Ranking Great Comets, was Re: Recording The "Brightness" of Comet Lovejoy's Tail

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  • 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 1 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 2 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 3 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 4 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 5 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 6 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 7 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]
                  >
                  >
                  >
                  > ------------------------------------
                  >
                  > Comet Observations List: http://groups.yahoo.com/group/CometObs/
                  > Comet Images List: http://groups.yahoo.com/group/Comet-Images/
                  >
                  > NOTICE: Material quoted or re-posted from the Comets Mailing List should be indicated by:
                  >
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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 8 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 9 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]




                      [Non-text portions of this message have been removed]
                    • 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 10 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 11 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 12 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 13 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 14 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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