Comets are small bodies made out of dust and ice: "dirty snowballs". The term "comet" derives from the Greek "aster kometes", which means "long-haired star": a reference to the tail.

Once thought to be phenomena in our atmosphere, we have known since the observations of Tycho Brahe that they are parts of the Solar System well beyond Earth's atmosphere. Most are on long elliptical orbits (perhaps parabolic in some cases) that take them from the outer reaches of the Solar System to the vicinity of the Sun. If they come near the Sun they are heated and emit gases and dust that are swept by the Solar Wind into the characteristic tail that consequently always points away from the Sun.

Source of the above information: Hubble site.and other websites.
More about comets at the CalSky site, where you also can use the toolbar for further exploration, such as: This Night's Comets; Orbital Curves; Ephemerides and Perigees.
Most of my Comet images can also be viewed in this

Here is my collection of Comets:

4P/Faye

Hervé Faye (Royal Observatory, Paris) discovered this comet on 1843 November 23.04, near Gamma Orionis. The comet exhibited a distinct nucleus, which emitted faint indications of a tail extending 4 arcmin away from the sun. Due to cloudy weather, Faye was not able to confirm his discovery until November 25.21.

Here is a LOT more about this comet.

Comet 4P/Faye.
December 15, 2006 19:31 - 20:05 UT.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm], Vesta Pro-SC3a b/w RAW webcam, Baader Infra Red Blocking Filter.
30 unguided exposures of 30 seconds.
On the left image I aligned at the comet which causes the stars
to become streaks thus showing that the comet is passing through the skies.


Comet 4P/Faye.
October 16, 2006 23:11 - 23:31 UT.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm], Vesta Pro-SC3a colour RAW webcam, Baader Infra Red Blocking Filter.
33 unguided exposures of 20 seconds.





This overview comes from this website.

8P/Tuttle

Horace Parnell Tuttle (Harvard College Observatory, Cambridge, Massachusetts) discovered this comet on 1858 January 5.01. He described it as "rather faint, but not so much so as to afford any difficulty in observing it with the great refractor." Karl Christian Bruhns (Berlin, Germany) independently discovered this comet on January 11.89. He described it as "a very large diffuse object without nucleus and distinct border." By that time, several observatories had already confirmed Tuttle's discovery, so Bruhns' name was not attached to this comet.

Here is more about this comet.


Comet 8P/Tuttle.
December 29, 2007 19:20 - 19:31 UT.
I assume that this comet is travelling fast, as you can see my sequence of imaging: L-R-G-B; next time I will use a colour camera.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 10x30s; RGB: 5x16s; unguided.

Comet 8P/Tuttle.
December 29, 2007 19:26 - 19:31 UT.
This image only contains the RGB components and is aligned on the comet: the stars show the RGB sequence of imaging.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik RGB filters.
Exposures: RGB: 5x16s; unguided.

17P/Holmes

APOD reports the following:
"Comet 17P/Holmes stunned comet watchers across planet Earth earlier this week. On October 24, it increased in brightness over half a million times in a matter of hours. The outburst transformed it from an obscure and faint comet quietly orbiting the Sun with a period of about 7 years to a naked-eye comet rivaling the brighter stars in the constellation Perseus"
Here is a plot of what happened on October 24, 2007
APOD has the following pages about this comet:
October 26, 2007, October 29, 2007, October 30, 2007, November 3, 2007, November 5, 2007, November 9, 2007, November 10, 2007, November 13, 2007, November 17, 2007, November 21, 2007, November 28, 2007, December 5, 2007

And here is the contribution of the BBC and a MUST READ: the highly interesting pages of Gary Kronk: Page 1 and Page 2

On October 30, 2007 I finally had clear skies so that I could see and image for myself.
Wow, that is the biggest comet I have ever seen: I am deeply impressed !

Please view this COMET 17P/HOLMES ASTROSHOW


Comet 17P/Holmes has passed the bright star Algol, Beta Persei and is fading away ...
January 30, 2008 18:06 - 18:24 UT.
Distance 360.5 million km.
Imaging: 35mm SLR Photolens, ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 15x30s; RGB: 5x30s; unguided.

Comet 17P/Holmes close to Algol (Beta Persei).
January 13, 2008 18:08 - 18:25 UT.
Imaging: 35mm SLR Photolens, ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 15x30s; RGB: 5x30s; unguided.

Comet 17P/Holmes.
December 28, 2007 19:25 - 20:03 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 13x120s; RGB: 3x60s; unguided.

Comet 17P/Holmes.
December 22, 2007 20:26 - 20:41 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 5x60s; RGB: 5x30s; unguided.

Comet 17P/Holmes.
December 18, 2007 20:39 - 21:30 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 20x120s; RGB: 5x30s; unguided.

Comet 17P/Holmes.
December 17, 2007 19:55 - 20:16 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 10x60s; RGB: 5x30s; unguided.

Comet 17P/Holmes.
December 16, 2007 19:56 - 20:02 UT.
I measured the size of the coma: approx. 57 arc minutes across.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik Luminosity filter.
Exposures: L: 6x60s, unguided; RGB: not captured because of arriving clouds.

Comet 17P/Holmes.
November 29, 2007 22:24 - 22:33 UT.
I measured the size of the coma: just over 47 arc minutes across.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 5x30s; RGB: 5x15s, unguided.
Comet 17P/Holmes and the 13 day 21 hour old moon.
November 23, 2007 20:30 - 20:52 UT.
This image gives an idea of the size of the comet.
Comet image: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 3x30s; RGB: 3x15s each; unguided.
Moon image: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik Ha filter.
Exposures: Ha: 30x 0.0010s; unguided.
Comet 17P/Holmes and the 11 day old moon.
November 21, 2007 19:59 - 20:46 UT.
This image gives an idea of the size of the comet.
Comet image: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 10x30s; RGB: 10x15s each; unguided.
Moon image: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik Ha filter.
Exposures: Ha: 17x 0.0010s; unguided.

Comet 17P/Holmes approaching Mirfak (alpha Persei): animation.
November 16 and 18, 2007.
Animation made from my images of these dates.

Comet 17P/Holmes.
November 18, 2007 00:07 - 00:15 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 10x12s; RGB: 5x12s each; unguided.

Comet 17P/Holmes.
November 16, 2007 23:06 - 23:09 UT.
This wide field image [approx 2x1.5 arc degrees] nicely shows the size of the comet.
Imaging: 135mm SLR Photolens, ATK16IC camera, Astronomik L filter.
Exposures: L: 10x15s; unguided.

Comet 17P/Holmes.
November 16, 2007 22:59 - 23:02 UT.
This wide field image [approx 5x4 arc degrees] nicely shows the size of the comet.
Imaging: 50mm SLR Photolens, ATK16IC camera, Astronomik L filter.
Exposures: L: 10x15s; unguided.

Comet 17P/Holmes.
November 16, 2007 21:59 - 22:12 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 13x30s; R: 5x15s; G: 5x14s; B: 5x13s; unguided.

Comet 17P/Holmes.
November 14, 2007 21:04 - 21:17 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 10x30s; RGB:5x15s; unguided.

Comet 17P/Holmes.
November 12, 2007 22:27 - 22:32 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik L filter.
Exposures: L: 10x30s; unguided.

Comet 17P/Holmes.
November 11, 2007 22:44 - 22:57 UT.
My first LRGB image of this comet.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 10x30s; R: 5x15s; G: 5x14s; B 5x13s; unguided.

Comet 17P/Holmes - 95 hour motion.
November 7, 2007 20:07 - 20:16 UT and November 11, 2007 19:47 - 19:55 UT.
This animation is a combination of 2 images I captured on the above dates.
It nicely shows the motion of the comet in roughly 4 days.

Comet 17P/Holmes.
November 11, 2007 19:47 - 19:55 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik L filter.
21 unguided exposures of 10 seconds.

Comet 17P/Holmes - 13 hour motion.
November 7, 2007 07:03 and 20:07 - 20:16 UT.
This animation is a combination of an image captured by comet expert Gary Kronk and my own image of November 7, 2007.
It nicely shows the motion of the comet in roughly 13 hours. This animation could only be made by intercontinental cooperation.
Of course you can see the same animation on the website of Gary Kronk where a lot of background information plus a wealth of other images is waiting for you.

Comet 17P/Holmes.
November 7, 2007 20:07 - 20:16 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik L filter.
31 unguided exposures of 10 seconds.


Comet 17P/Holmes.
November 6, 2007 00:47 - 00:53 UT.
While imaging I looked at the comet through my 7x50 binoculars: wow !!!!
After processing this image I stretched the histogram and then measured the diametre of the then visible comet: almost 18 arc minutes.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3.63 [focal length 290 mm] ,
Vesta Pro-SC3a colour webcam, Baader Infra Red Blocking Filter.
65 unguided exposures of 4.5 seconds.




Rotational gradient: the jet stream is very well visible.

This overview comes from this website.

Comet 17P/Holmes, imaged with 99.9% cloud cover.
November 3, 2007 22:31 - 23:07 UT.
This is the first image I captured with the use of a recently received adapter - donated by a generous astro friend - I now can mount my Meade 3.3 Focal Reducer [with SCT thread] on the 2-inch eyepiece holder of my William Optics Zenithstar 80 ED II APO.
This image has been captured under almost impossible consitions: just read the text below the larger image.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3.63 [focal length 290 mm] ,
Vesta Pro-SC3a colour webcam, Baader Infra Red Blocking Filter.
17 unguided exposures of 6 to 9 seconds.
Processing as per my DSO tutorial plus PDark from Sylvain Weiller.

Comet 17P/Holmes.
October 30, 2007 21:11 - 21:59 UT.
Imaging: William Optics Zenithstar 80 ED II APO, f/6.8 [focal length 545 mm] ,
Vesta Pro-SC3a colour webcam, Baader Infra Red Blocking Filter.
179 unguided exposures of 15 seconds.
Processing as per my DSO tutorial; this image is aligned on the comet and thus the stars have trails.

Comet 17P/Holmes.
October 30, 2007 21:11 - 21:59 UT.
Imaging: William Optics Zenithstar 80 ED II APO, f/6.8 [focal length 545 mm] ,
Vesta Pro-SC3a colour webcam, Baader Infra Red Blocking Filter.
179 unguided exposures of 15 seconds.
Processing as per my DSO tutorial; this image is aligned on the stars and thus the comet is slightly elongated.

Comet 17P/Holmes.
October 30, 2007 21:11 - 21:59 UT.
Rotational Gradient revealing the jets coming from the comet.
Processing as per my Rotational Gradient Tutorial

Comet 17P/Holmes.
October 30, 2007 20:02 - 20:30 UT.
I measured the size of the comet including the surrounding halo at 7 arc minutes 31 arc seconds.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm], Vesta Pro-SC3a colour webcam, Baader Infra Red Blocking Filter.
80 unguided exposures of 20 seconds.
Processing as per my DSO tutorial; this image is aligned on the comet and thus the stars have trails.

Comet 17P/Holmes.
October 30, 2007 20:02 - 20:30 UT.
I measured the size of the comet including the surrounding halo at 7 arc minutes 31 arc seconds.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm], Vesta Pro-SC3a colour webcam, Baader Infra Red Blocking Filter.
80 unguided exposures of 20 seconds.
Processing as per my DSO tutorial; this image is aligned on the stars and thus the comet is slightly elongated.

Comet 17P/Holmes.
October 30, 2007 20:02 - 20:30 UT.
I measured the size of the comet including the surrounding halo at 7 arc minutes 31 arc seconds.
To reveal the blue halo I stretched the histogram so that I could measure the diameter via my FOV measuring method

73/P Schwassmann-Wachmann 3

Arnold Schwassmann and Arno Arthur Wachmann (Hamburg Observatory, Bergedorf, Germany) discovered this comet on photographs exposed for a minor planet survey on 1930 May 2.

In December 1995 observatories reported that this comet had broken up into multiple pieces.
I imaged part "B".
Here is a LOT more about this comet.






Comet 73/P-B Schwassmann-Wachmann.
April 10, 2006 22:58 - 23:20 UT.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm], Vesta Pro-SC3a colour webcam, Baader Infra Red Blocking Filter.
32 unguided exposures of 40 seconds.
Camera settings: Brightness 50, Gamma 58, White Balance automatic, Gain 56.
Seeing: 7/10, transparency 6/10, bright 12 day old moon.
Processing as per my DSO tutorial; for this image I aligned at the comet which causes the stars to become streaks thus showing that the comet is passing through the skies.
I used K3CCDTools to measure the length of the star trail: approximately 29 arc seconds, so roughly 79.1 arc seconds per hour


The same AVI, but now I aligned at the stars:
the bright line of the comet shows the distance the comet has travelled in 22 minutes.
Calsky reports the following:
hourly motion: dRA= 86.8"/h dDec= 55.5"/h.
I used K3CCDTools to measure the length of the star trail: approximately 29 arc seconds, so roughly 79.1 arc seconds per hour

Comet 73/P-B Schwassmann-Wachmann: measuring the distance.
This collage shows how I measured the distance this part of the comet travelled during the 22 minutes I imaged.
April 10, 2006 22:58 - 23:20 UT.
This - non clickable - animation shows that this comet travels fast:
Calsky reports the following:
hourly motion: dRA= 86.8"/h dDec= 55.5"/h.
I used K3CCDTools to measure the length of the star trails in my image: approximately 29 arc seconds, so roughly 79.1 arc seconds per hour.

C/2004 Q2 - Machholz

This comet was discovered by Don Machholz and therefore carries his name.

January 12, 2005 18:41 - 19:28 UT.
During this period of 38 minutes C/2004 Q2 - Machholz covered a distance of approximately 3.5 arc minutes.
The left hand image is made with the K3CCDTools 'if lighter' feature.
Both images clearly demonstrate that the comet moves at high speed through the skies


January 15, 2005 19:00 - 19:39 UT .
C/2004 Q2 - Machholz.
Imaging Details: 135mm SLR Photolens, SC3a colour camera, Baader Infra Red Blocking Filter, 31 exposures of 30 seconds, unguided.
Seeing: 9/10, transparency: 9/10, urban light pollution.

January 14, 2005 19:55 - 20:35 UT.
C/2004 Q2 - Machholz.
Imaging Details: 135mm SLR Photolens, SC3a colour camera, Baader Infra Red Blocking Filter.
Seeing: 6/10, transparency: 4-6/10,urban light pollution and thickening fog.

January 12, 2005 18:41 - 19:28 UT.
C/2004 Q2 - Machholz.
Imaging Details: 200mm SLR Photolens, SC3a black/white raw camera.
First light for my 200mm SLR Photolens.

January 8, 2005 18:51 - 18:56 UT.
C/2004 Q2 - Machholz.
Imaging Details: 135mm SLR Photolens, SC3a black/white raw camera.

January 6, 2005 21:14 - 21:19 UT.
C/2004 Q2 - Machholz, imaged with 135mm SLR Photolens.
The comet is just passing star GSC 1247:684 [see Megastar skychart]

January 6, 2005 20:24 - 20:32 UT.
C/2004 Q2 - Machholz [with M45].
Imaged with 29mm SLR Photolens.

C/2007 N3 - Lulin

This comet was discovered at Lulin Observatory in Taiwan in July 2007.
A MUST READ: the highly interesting website of Gary Kronk about C/2007 N3 (Lulin)


This overview comes from this website.
Comet C/2007 N3 - Lulin [animation of the racing Comet]
March 2, 2009 20:00 - 21:13 UT.
Of the 130 frames captured I used 1/3 for this [7 Mb !!] animation [done with K3CCDTools].
Shortly after the start of the animation you can see an airplane moving in the lower left corner; at the end of the animation something seems to encounter the comet, most likely a satellite.

Comet C/2007 N3 - Lulin [the racing Comet]
March 2, 2009 20:00 - 21:13 UT.
Based on the frames captured I made 2 versions: one aligned on the comet and one aligned on the stars; both versions nicely show that this comet is a real racer!
Just move your mouse in/out the image to alternate the images.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik L filter.
Exposures: L: 130x30s [1x1]; all unguided.

Comet C/2007 N3 - Lulin
March 2, 2009 19:28 - 19:30 UT.
An attempt to image the comet with my SC3 modified webcam.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], Philips Vesta SC3 colour webcam, Baader Infrared Blocking Filter.
Exposures: 10x10s; all unguided.

Comet C/2007 N3 - Lulin and 4 Galaxies.
February 28, 2009 22:23 - 22:34 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 5x120s [1x1]; RGB: 5x30s [2x2]; all unguided.

Comet C/2007 N3 - Lulin and 4 Galaxies.
February 28, 2009 22:12 - 22:20 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik L filter.
Exposures: L: 5x120s [1x1]; unguided.

Comet C/2007 N3 - Lulin and 4 Galaxies: animation
February 28, 2009 22:12 - 22:20 UT.
This animation clearly shows how fast this comet travels.
The animation was prepared in K3CCDTools [text added with the Output Filter], Photoshop [curves and levels] and Animagic [animation].