From 14 to 20 Dec 2004, I made some pictures of the now extinct comet (3200) Phaethon. Seiichi Yoshida directed an international campaign in order to detect an eventually tail of this object. (3200) Phaethon is believed to be the ancestor of the geminid meteor shower. The results of the observational campaign are here.
Still images of C/2004Q2 Machholz taken at Gnosca in winter 2004/05. Gianluca Cassina measured the absolute escape velocity of the ion tail obtaining 200 ± 60 km/s in the evening of 4 Jan 2005.
I assembled some gif images showing the motion of the dust tail.
2005_01_04 (8 MB)
2005_01_05 (10 MB)
2005_01_08 (2 MB)
2005_01_10 (10 MB)
2005_01_14 (5 MB)
The comet 51P Harrington showed 2 comas.
The comet P/2004V5 LINEAR-Hill also broke in several pieces.
The outburts of the comet 17P/Holmes photographed between the clouds
from Gnosca. With an angular diameter of 2,5 arcmin it is roughly 4 times larger than
the angular diameter of Jupiter. Now the comet is a naked eye object in the Perseus constellation. 1s exposure with a Newtonian 40cm f/4.
The outburts of the comet 17P/Holmes photographed from Gnosca. 1s exposure with a Newtonian 40cm f/4.
The outburst of Comet 17P Holmes imaged in the winter season 2007/08. The images were taken at the observatory. The addition and assembly were made by Jonathan Muri.
Jonathan also calculated the absolute expansion velocity of the coma from October to January:
“SUNWARD” EXPANSION: 324 ± 23 m/s.
“LEFT” EXPANSION: 432 ± 26 m/s.
“RIGHT” EXPANSION: 450 ± 27 m/s.
The “sunward” expansion was about 70% of the lateral expansions (left or right).
Taking into account only the first two days, from 27 to 28 Oct, the expansion velocity was:
“SUNWARD” EXPANSION: 582 ± 37 m/s.
Extrapolating back, the outburst time occured the: 24 OCT 2007 at 07:30 UTC ± 6H.
I assembled 83 x 30 s CCD images to produce this animation of comet C/2007N3 (Lulin).
The animation spans about 1 h and one can see the movement of the ion tail.
No special filters or processing techniques were used.
Date: 17 Feb 2009 Time: from 00:51 UT to 00:52 UT.
I assembled 500 x 30 s CCD images to produce this animation of comet C/2007N3 (Lulin).
The animation spans about 5 h. The very beautiful movement of the ion tail can be seen.
Date:21-22 Feb 2009 Time: from 23:00 UT to 03:53 UT.
I assembled 604 x 30 s CCD images to produce this animation of comet C/2007N3 (Lulin).
This 12 s animation compress about 6 h real time.
Date: 24-25 Feb 2009 Time: from 20:40 UT to 02:43 UT.
C2006 A1 (Pojmanski)
The comet C/2006 A1 (Pojmanski) photographed in the morning sky of the 14th march 2006 without filters. 37 20-s CCD images were taken. Angular dimensions of the image: 20 x 15 arcmin.
North is up. East is left.
C2005 A1 (LINEAR)
The two comas of the comet C/2005A1 LINEAR photographed in the night of 2005 September 29th. They are 19 arcseconds apart and their luminosities are of 17 mag and 19 mag. North=up ; East =left