|Jan 02 2002 00:18:07
| ||Jan 02 2002 15:50:29
Another informational notice:
Those good folks at LASCO have created more useful internet stuff
for you to use. Running difference real-time movies are
available at http://lasco-www.nrl.navy.mil/rtmovies.html
These images are excellent for identifying comets as they maximize
the contrast. It's the way I usually look at the data.
|Jan 05 2002 15:12:55
possible Kreutz comet in C2 images
b/w 512*512 from the lasco website
enlarged to 1024*1024
0,0 in upper left corner
time (Jan 05) x,y
1854 42, 748
1931 72, 712
1954 92, 690
2006 100, 678
|Jan 05 2002 15:44:07
Don't consider my report Jan 05 2002 15:12:55
nothing visible in 1024*1024 at 1954
|Jan 06 2002 06:18:11
If you look carefully you can see 96P (Machholz) near the edge of
the C3 field of view a little below the oculting bar. My guess is mag. 9 and it looks decidingly elongated.
Anyone else see it?
|Jan 06 2002 08:54:54
Dear Terry, dear all.
Actually 96P/Machholz starts to be visible at the left side of
the pylon in 12:42 b/w. It is very bright, brighter than
expected - estimation: ~ mag 3.5 (with pylon obstruction!)
Perhaps it is only visible in b/w due to the gif mask.
Positions (0,0) upper left, 512 x 512
|Jan 06 2002 08:59:18
I think 96P is just emerging from the oculting bar
in C3 1342 UTC 166,834 (0,0) upperleft corner
|Jan 06 2002 09:55:00
OK Sebastian, 96P is now really visible on two B&W images at 12:42
and 14:42 UT. It's very bright and elongated.
|Jan 06 2002 20:17:30
It's great to see Periodic Comet Machholz 1 doing well
in these SOHO images. I've been looking forward to its
passage through the C3 field for some time now.
P/96 is the periodic comet (comets with orbital periods
of under 200 yrs) with the 5th shortest period (5.24 yrs)
and goes closest to the sun (0.10AU) than any other known
periodic comet. Because of it's closeness to the sun, and
because of the way it behaves, it gets brighter, on a con-
sistant basis, than any other periodic comet. The problem
is that when it is at its brightest it is close to the sun
and not visible in dark sky. In large instruments it is
also visible at aphelion (~5 AU).
The comet is known to outburst at times so let's keep an eye
on it. One theory is that it is only a mile across, the other
theory is that it is large and mostly dormant. Its last
passage through the SOHO field was on Oct. 15, 1996.
FYI, the comet was discovered on May 12, 1986 from the Santa
Cruz Mtns near San Jose in California. I found it two degrees
south of M31. It was mag. 10 and slowly dimming.
You SOHO comet guys are doing a hearty job of searching for
comets. I'm pleased to join you for these next few days
as the comet crosses the field.
|Jan 07 2002 05:43:05
As an addition here is a reference that might be useful for those
who have a further interest in this comet:
"Periodic Comet Machholz and its idiosyncrasies"
Astronomical Journal, vol. 99, April 1990, p. 1268-1277, 1378
It is downloadable via the NASA Astrophysics Data System (ADS).
|Jan 07 2002 12:03:03
Possible comet in C2 image
positions 512x512 (0,0) top-left corner
Object faint on a Kreutz orbit
|Jan 07 2002 23:58:49
|Jan 08 2002 00:05:35
|Jan 08 2002 09:36:59
96P/Machholz has entered C2 at 04:54 UT.
|Jan 08 2002 10:37:16
Why doesn't the tail look perpendicular
to the sun/occulting disk? I thought
a comet's tail would slowly rotate
counter clockwise pointing away as it
neared the Sun.
|Jan 08 2002 15:38:29
Wow! What a nice comet Don Machholz provided for us. We're taking
lots of images that don't show up in the real-time images. Primarily,
we're taking images with shorter exposure times toprevent saturation.
Unfortunately, even some of those are saturated. Looks like the
comet reached at least magnitude -1. About the tail. I think
there are a few considerations. First, we are seeing it in projection.
So, the bulk of the tail may very well be pointing at least roughly
radially. But also, comets at 1 AU and beyond are trudging along.
This comet is smoking, on the order of 100 km/s. Thus, the motion
of the comet significantly affects the tail direction, as radiation
pressure is a relatively weak force and takes time to push
the tail out.
I have not been able to find anything at the locations of the
Jan 6 object claimed by T. Scarmato.
The positions reported by Zheng Yin are positions for 96P/Machholz.
|Jan 08 2002 20:10:39
The tail's bending behind the comet is an effect of
differential orbital angular momentum, caused by
radiation pressure. Eventually the comet will have
two tails, one to the north (new ejecta) and the one
to the southeast (old ejecta). The sector in between
will also be filled with material, which will only
faintly be seen.
|Jan 09 2002 01:56:47
| ||Jan 10 2002 13:09:58
Possible not Kreutz comet in c3
positions 512x512(0,0) top-left corner
I am waiting other images to confirm
|Jan 10 2002 13:25:54
Not consider my last report.
No object visible at 18:18
|Jan 10 2002 22:12:49
Possible comet in C2 realtime images
(1024 x 1024 format, 0,0 in upper left corner)
|Jan 11 2002 17:22:17
Wow! Wasn't that a great comet? I want to thank Don Machholz for
providing us with what is definitely the best comet seen with LASCO
thus far. Many of you may have noticed an apparent reduction in
the number of C3 pictures. That's because the real-time movies
only show the standard 19sec exposures. In fact, in between each
of those 19sec exposures we took a 5sec exposure. Thus, preventing
saturation and enabling us to do photometry. However, even these
exposures saturated slightly right at perihelion. Due to this,
there is some uncertainty in the magnitude estimates. However,
it appears to have reached at least -0.6 and it may have peaked
at just about -1. And wasn't that tail fantastic?
One of many sites to feature this comet in LASCO:
Now back to those `boring' old sungrazers.
|Jan 14 2002 09:06:09
I do not believe that the claim of T. Hoffman for an object in
C2 on Jan 11 is anything other that cosmic rays. One of the
reasons is the apparent shape of the points indicated. Any
astronomical object imaged with the telescope must of course
have the light pass through the telescope. This light, due to
a variety of effects, is not focused perfectly. The resulting
image is always slightly spread out. Cosmic rays interacting
in the CCD, do not exhibit this spreading.
|Jan 14 2002 14:38:22
Sorry for the late noteice. Last week, it was determined that
spacecraft momentum management and station-keeping maneuvers were
necessary. These will take place tomorrow. Thus, the LASCO doors
will be closing at about 22 UT today and we expect to re-open them
at about 16 UT on Thursday (Jan 17). Take a welcome break everyone.
|Jan 15 2002 00:00:51
| ||Jan 15 2002 02:32:09
| ||Jan 16 2002 08:07:58
Well, it took a long time, but we have finally acted on a
couple of old reports. First, we have accepted the report
of X. Zhou of a comet on 18 Dec 2001 in C2. The rough
position measurements are given below. Second, we were
considering a claim by T. Scarmato for a comet on 25 Apr
2001 also in C2. For that object, we believe it likely
to be a real comet, but it doesn't meet our minimum
criteria, thus, we are adding it to our 'denied' list.
This is a list we keep only for comets where there is
doubt remaining. These are comets that don't meet
our criteria but which also show some compelling evidence.
# HEIGHT DATE TIME ANGLE TEL FC COL ROW
7.88 2001/12/18 05:54:05 138.7 C2 10 77.0 8.0
7.79 2001/12/18 06:06:05 138.3 C2 10 79.0 17.0
7.60 2001/12/18 06:30:06 137.5 C2 10 83.0 35.0
7.41 2001/12/18 06:54:05 136.6 C2 10 87.0 54.0
7.10 2001/12/18 07:32:17 135.4 C2 10 96.0 82.0
6.91 2001/12/18 07:54:34 134.5 C2 10 101.0 100.0
6.60 2001/12/18 08:30:05 132.9 C2 11 110.0 130.0
6.39 2001/12/18 08:54:06 131.9 C2 10 116.0 149.0
6.28 2001/12/18 09:06:05 131.3 C2 10 120.0 159.0
6.07 2001/12/18 09:30:05 130.1 C2 10 126.0 179.0
|Jan 17 2002 00:35:34
|Jan 17 2002 00:36:30
c3 20020114_2147_c3 (502,212)
|Jan 19 2002 03:32:18
| ||Jan 20 2002 16:46:55
Possible comet in C3 realtime images
(512x512 format 0,0 upper left corner
|Jan 21 2002 12:26:04
Possible comet in C3 realtime images
(512x512 format 0,0 upper left corner)
|Jan 22 2002 08:38:03
I am unable to confirm the report of A. Roca. The first 3 points
appear to be just random cosmic rays and the fourth point is a
star. Note, the chaotic motion of the points indicated are not
what one would expect for a physical object.
|Jan 23 2002 10:47:23
Just a note that I neglected to include the planet Neptune
on the C3 transits list. It is currently visible in LASCO C3. It
entered the FOV on Jan 20th. Rough position measurements are given
below. It appears to the left of the brightish star Upsilon
Capricorn (m=5.2) (SAO# 163779 and HD# 196777) and just to the
right of an m=7.3 star designated as SAO# 163811 and HD# 197187.
# HEIGHT DATE TIME ANGLE TEL FC COL ROW
29.20 2002/01/20 12:42:05 83.8 C3 10 10.0 586.0
28.54 2002/01/20 17:18:05 83.8 C3 10 21.0 585.0
27.83 2002/01/20 21:42:05 83.8 C3 10 33.0 584.0
26.94 2002/01/21 02:42:05 83.8 C3 10 48.0 582.0
26.35 2002/01/21 06:42:06 83.8 C3 10 58.0 581.0
25.70 2002/01/21 11:18:05 83.8 C3 10 69.0 580.0
24.88 2002/01/21 15:42:05 83.7 C3 10 83.0 579.0
24.11 2002/01/21 20:42:06 83.8 C3 10 96.0 577.0
23.29 2002/01/22 01:42:16 83.7 C3 10 110.0 576.0
22.71 2002/01/22 05:42:05 83.7 C3 10 120.0 575.0
22.01 2002/01/22 10:20:37 83.6 C3 10 132.0 574.0
21.37 2002/01/22 14:42:05 83.6 C3 10 143.0 573.0
20.63 2002/01/22 18:42:05 83.4 C3 10 156.0 573.0
19.92 2002/01/22 23:42:05 83.5 C3 10 168.0 571.0
19.17 2002/01/23 04:18:05 83.6 C3 10 181.0 569.0
|Jan 24 2002 11:09:25
Possible sungrazer comet in a real-time B&W C3 images now.
The object is fairly bright, small, and it's visible in 3 consecutive images
on 2002/01/24 from 14:42 to 15:42 UT on the left of the pylone.
The object is moving towards the sun.
Approximate positions measured from the top-left corner
of a 512x512 frames :
14:42 UT 77,384
15:18 UT 80,381
|Jan 24 2002 11:13:55
Ignore my previous report, it's not real.
|Jan 26 2002 05:00:53
Possible comet or minor planet on c3 field of view.
I did not find it on the debris list.
A fearly bright spotlike object is moving from left to
right horizontally above the Sun on C3 images.
Entering at 2002. jan 24. 2:42 UT, and still visible
at 2002 jan 26 6:16 UT.
Its brighness was at maximum when entered, and becoming
more and more dimmer since then.
Positions on C3 512x512 images:
2002 jan 24 2:42: (5,136)
24 5:42: (13,136)
24 11:18: (30,136)
24 21:56: (61,136)
25 5:18: (83,136)
25 18:18: (121,135)
26 6:18: (157,135)
|Jan 26 2002 05:44:23
Please ignore my previous alarm.
The object seems to be the Mercury.
|Jan 31 2002 16:01:16
In SOHO Lasco c3 images, an object passes thru the field from L to R starting somewhat before 1/25 and exiting to the right side on 1/31 (today). Object is above the sun, about halfway up the picture, moving from left to right. If this is an identified comet, which one is it?
|Jan 31 2002 16:22:27
That would likely be the good comet Neptune? See C3 Transits for greater certainty.
|Jan 31 2002 16:46:29
Just to clarify the situation. For the past week, 3 planets were
visible in the LASCO images. Venus is the very bright one moving
from right to left, below the Sun. Mercury was the fast moving
one above the Sun, moving left to right. Neptune is moving at
about the same speed as the stars, from left to right. It's
pretty much at the same height in the images as the Sun.