Comet C/2006 P1 (McNaught)

Toni Scarmato’ Observatory

Lat. 38° 42’ 00” N – Long. 16° 00’ 42” E – 186 m above the sea level

Astronomical Association San Costantino di Briatico (VV)

CARA Project Comet Section UAI


Comet C/2006 P1 (McNaugth) have produced an iron tail.

The discovery in the preprint article on Ap.J.




Comet C/2006 P1 was discover by Rob McNaught  during the course of the Siding Spring Survey, on August 7.51. The object was 17th magnitude

and reaches perihelion at 0.17 AU in mid January 2007.



Orbital Elements

The following orbital elements are taken from MPC 58538:

C/2006 P1 (McNaught)
Epoch 2007 Jan. 20.0 TT = JDT 2454120.5
T 2007 Jan. 12.7968 TT                                  MPC
q   0.170729             (2000.0)            P               Q
z  -0.000122       Peri.  155.9756      +0.1269047      -0.1739167
 +/-0.000024       Node   267.4148      +0.6752906      +0.7362755
e   1.000021       Incl.   77.8348      +0.7265520      -0.6539506
From 194 observations 2006 Aug. 7-Dec. 3, mean residual 0".4.

Elements are also available for the current standard epoch:

C/2006 P1 (McNaught)
Epoch 2007 Apr. 10.0 TT = JDT 2454200.5
T 2007 Jan. 12.7961 TT                                  MPC
q   0.170742             (2000.0)            P               Q
z  -0.000109       Peri.  155.9771      +0.1269048      -0.1739154
 +/-0.000024       Node   267.4144      +0.6753090      +0.7362590
e   1.000019       Incl.   77.8349      +0.7265348      -0.6539695




Visual magnitude in ICQ format:

Comet C/2006 P1

C2006P1  2007 01 07.68 S  -1.0 TI 5  B     7      2s8            ICQ    SCA02


I want to post some information.  Using Starry Night (that is wrong) i saw that at my local time the comet is a 1deg and 23' above the horizon and Altair 19 deg.

But after a discussion with my friend Roberto Haver, I Have revisited in my mind the observation.  The comet really was at about 3 deg above the horizon and Altair 22 deg at 17:30 local time in my 7x50b.  I Have esteemed the comet defocusing before Altair and after the comet.  Because the degree of condensation of the comet is too high I have esteemed in a first moment the comet at the same brightness of Altair.  But in a second moment I Have esteemed the comet fainter than Altair of about 1 magnitude.  Unfortunately there is no another star to comparison. I Have no used Venus!!!

The sky at the level of Altair was very clear and transparent so I can to assume that the extinction is 0.

The extinction for the comet is 4.83 at z=87, but I can to say that the transparence was very high for the altitude, so I can to assume that the extinction was low of he average value.  I can to assume that I Have an extinction of about 3 magnitude.

In this way the comet was at m1=-1.0 more reliable value.  




Note the strong variation of the brightness and shape of the comet. Visible clearly to naked eye, in binoculars I saw the same things visible in the previous image. 

The tail long at least 1 deg and a central condensation much marked.   (See the animation: movic2006p120070109.avi 1,36 MB)


C2006P1  2007 01 09.68 S  -2.5 TI 5  B     7      4s9            ICQ    SCA02




C2006P1  2007 01 10.68 S  -3.2 TI 5  B     7      2s9            ICQ    SCA02


Another good observation of the comet with a very clear sky at low altitude above the horizon.



C2006P1  2007 01 11.68 S  -3.5 TI  naked eye     2s9            ICQ    SCA02






C2006P1  2007 01 12.66 S  -3.9 TI  naked eye     3s9            ICQ    SCA02





C2006P1  2007 01 13.65 S  -4.7 TI  naked eye     4s9            ICQ    SCA02

C2006P1  2007 01 14.66 S  -5.4 TI     5 B 7            4s8            ICQ    SCA02




Courtesy NASA-ESA









The Biggest Dust Tail of All Times.

By M. Fulle

Composition of two photos of Comet McNaught 2006P1 taken on 20 January
2007 (at left, S. Deiries, ESO) from the southern hemisphere (Cerro
Paranal, Chile) and on 19 Januray 2007 (at right, M. Fulle, APOD 24
January) from the northern hemisphere (Carnic Alps, Italy): the tail was
so long to need observations from both hemispheres to be photographed in
all its extension. The image covers 65 degrees of declination, from -50
deg in Grus (left) to +15 deg in Pegasus (right), equivalent to about
150 million km, close to the Sun-Earth distance. Positions of the set
Sun, of the one-day-old Moon, and of planet Uranus are plotted. The comet
moves on an almost precisely parabolic orbit, projected on the sky as a
dotted line. A dust tail can be modeled in terms of synchrones (dashed
lines) and syndynes (continuous lines), lines marking the size and the age
of the dust grains composing it. In particular, the synchrones are labeled
by the date of ejection from the comet nucleus (q is the perihelion day,
on 12 January 2007, followed by other seven days b.p., before perihelion);
the syndynes are labeled by the size in micron of the dust grains (assumed
to be spheres of bulk density 0.8 grams per cubic cm). These lines help us
to understand the complex nature of this tail. The nucleus ejects grains
of all sizes, up to several microns: shortly before the observations, the
tail is crossed by all the plotted syndynes. After ejection, the grains
(probably fluffy aggregates of silicates and ices) fragment due to solar
heat, creating subcomets which are blown away from the solar radiation
pressure. These subtails, lacking of a comet head, spread away from the
parent tail, which becomes more and more depleted of large dust. In fact,
the older the synchrone, the more external the respective syndyne best
fitting the inner boundary of the observed dust tail.










Remotely observation in Victoria Australia

2007 02 08




Updated………………. 2007 February 9


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