Seiichi Yoshida's Diary of Comet Observations (2008)

Japanese version
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Total 5,708 html files since Dec. 4, 1995
Updated on May 6, 2008

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Detailed observation data in ICQ format.

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* 2008 May 3 (2 comets)

I observed 2 comets visually on May 3 in Kita-karuizawa, Gunma, Japan.

The weather at night kept bad during the holidays. I could observe comets only for about 30 minutes in the evening on May 3, but the sky was very hazy.

On May 3, the sky was covered with clouds soon, and it kept cloudy all through the night. On May 4, it was very fine at daytime, however, clouds came during the evening glow and covered the whole sky before night.

C/2006 Q1 ( McNaught )

10.8 mag   Dia. 1.2'   DC 4   (40.0-cm reflector 144x)

Through thin clouds, so not easy to see.

C/2007 W1 ( Boattini )

7.8 mag   Dia. 9'   DC 3   (40.0-cm reflector 36x)

Very large! I guess it would have been larger and the estimation would have been brighter with a clear sky.

* 2008 Mar. 5 (14 comets + 1 asteroid)

I observed 14 comets and 1 asteroid visually on Mar. 5 in Mt. Hanadate, Ibaraki, Japan.

The weather forecast said that it would be getting fine. But the sky was covered with many clouds when I left home. A little snow felt on the way to Mt. Hanadate. But it became completely fine with no clouds when I arrived at Mt. Hanadate.

The weather had been fine with no clouds all night. Very dry, and the telescopes did not get wet at all. But the sky condition was not so excellent considering the visibility of the Milky Way. Especially, the evening low sky was bad, so I could not observe C/2008 A1 and 192P. But the condition was good to see planets. Saturn through a 40-cm telescope was a very fine view.

I also tried to observe 26P/Grigg-Skjellerup. I could see something very diffuse at 13 mag around the predicted position. But I looked up the ASAS-3 web site after I came back home, and found it was a cluster of three 14-mag stars.

C/2005 L3 ( McNaught )

13.9 mag   Dia. 0.6'   DC 7   (40.0-cm reflector 257x)

Very strongly condensed.

C/2006 Q1 ( McNaught )

11.4 mag   Dia. 0.9'   DC 4   (40.0-cm reflector 144x)

It located at the similar position when I observed it last time in December before it moved away to the southern sky. Extremely low, but I could see it.

C/2006 S5 ( Hill )

14.4 mag   Dia. 0.5'   DC 5   (40.0-cm reflector 257x)

It became much fainter than January.

C/2006 W3 ( Christensen )

14.7 mag   Dia. 0.3'   DC 4   (40.0-cm reflector 257x)

Locating near by a star. Very faint near limit. So very difficult to see.

C/2007 B2 ( Skiff )

14.4 mag   Dia. 0.6'   DC 5   (40.0-cm reflector 257x)

Very small and faint.

C/2007 G1 ( LINEAR )

fainter than 13.9 mag   Dia. 0.3'   (40.0-cm reflector 257x)

Not visible. It seems to have located on the dark nebula, and only a few stars exist around the area. So it was difficult to fix my eyes to the correct position.

C/2007 T1 ( McNaught )

10.7 mag   Dia. 1.9'   DC 4   (40.0-cm reflector 75x)

Very low, but clearly visible. But it was somewhat fainter than I have expected.

C/2007 W1 ( Boattini )

13.8 mag   Dia. 0.6'   DC 4-5   (40.0-cm reflector 257x)

Already bright and easy to see.

C/2008 C1 ( Chen-Gao )

10.3 mag   Dia. 3.5'   DC 3   (40.0-cm reflector 36x)

Bright. But unexpectedly, it is a large nebulous comet with a very weak condensation.

17P/Holmes

4.7 mag   Dia. 80'   DC 1   (5-cm refractor 10x)

I observed it after two months blank. Now it is hardly visible with naked eyes, only a hint of nebulous object was detectable. However, it is still very bright through a 5-cm refractor, the large nebulous diffuse comet is clearly visible.

29P/Schwassmann-Wachmann 1

13.3 mag   Dia. 1.3'   DC 1-2   (40.0-cm reflector 144x)

Two months after the outburst in January. But unexpectedly, the diffuse nebulous comet with no condensation is still bright and visible visually.

46P/Wirtanen

9.3 mag   Dia. 6.5'   DC 6   (40.0-cm reflector 36x)

Very bright and large. Strongly condensed and easy to see.

93P/Lovas 1

13.5 mag   Dia. 1.0'   DC 5   (40.0-cm reflector 144x)

Nobody had been observed it visually for last two months. But unexpectedly, it is still bright. I was surprised because it is still easily visible.

110P/Hartley 3

fainter than 14.2 mag   Dia. 0.4'   (40.0-cm reflector 257x)

Not visible.

2005 WY3

14.3 mag   DC 9   (40.0-cm reflector 257x)

Peculiar asteroid which passed the perihelion in January. It was much fainter than I have expected because locating in the low sky. So it is uncertain if the object is completely stellar.

* 2008 Jan. 5-6 (1 comet)

I observed 8P/Tuttle visually on Jan. 5 and 6 beside Tsurumi River in Yokohama City, Kanagawa, Japan.

Very bad condition due to the terrible city light pollution. Extremely difficult to see a 5-mag comet.

8P/Tuttle

Jan. 5   about 5.3 mag   Dia. 14'   DC 3-4   (10x66 monocular 10x)

Jan. 6   about 5.6 mag   Dia. 17'   DC 2-3   (10x66 monocular 10x)

* 2008 Jan. 3-4 (11 comets)

I observed 11 comets visually on Jan. 4 in Mt. Hanadate, Ibaraki, Japan. I also report observations of 8P and 17P on Jan. 3 in Fujishiro, Toride City, Ibaraki, Japan.

The weather was fine with no clouds until I ended my observations (but it became cloudy when I came back home). The sky was not so excellent at first, but it became better during my observations. I enjoyed two naked eye comets, 8P/Tuttle and 17P/Holmes, with unaided eyes.

C/2006 S5 ( Hill )

Jan. 4   13.4 mag   Dia. 0.6'   DC 4   (40.0-cm reflector 144x)

Near by a star, but visible bright.

C/2006 W3 ( Christensen )

Jan. 4   15.2 mag   Dia. 0.3'   DC 3-4   (40.0-cm reflector 257x)

Near by a star. It looked small.

P/2007 H1 ( McNaught )

Jan. 4   fainter than 13.7 mag   Dia. 0.5'   (40.0-cm reflector 257x)

It became too faint to see now.

8P/Tuttle

Jan. 3   5.4 mag   Dia. 24'   DC 3-4   (10x70 monocular)

Jan. 4   5.7 mag   Dia. 20'   DC 6   (10x70 monocular)

Diffuse in the city light pollution. However, strongly condensed in the mountain location, and visible with naked eyes.

17P/Holmes

Jan. 3   4.0 mag   Dia. 75'   DC 1   (5-cm refractor 10x)

Jan. 4   3.3 mag   Dia. 100'   DC D1   (naked eye)

Jan. 4   3.6 mag   Dia. 85'   DC 2   (5-cm refractor 10x)

Very bright in the mountain location! Easy object with naked eyes, and extraordinary large. Evidently brighter than 4 mag stars, so the comet is still around 3.5 mag!

In the city on Jan. 3, the comet looked faint due to the light pollution, which caused my estimation fainter.

29P/Schwassmann-Wachmann 1

Jan. 4   12.8 mag   Dia. 1.0'   DC 6   (40.0-cm reflector 144x)

Large, moderately condensed, and easy to see. I enjoyed the bright cometary 29P after a long time interval.

46P/Wirtanen

Jan. 4   9.6 mag   Dia. 6'   DC 5   (40.0-cm reflector 36x)

Surprisingly bright and large! It extends large, but the central condensation is strong well and easy to see.

50P/Arend

Jan. 4   14.6 mag   Dia. 0.4'   DC 6   (40.0-cm reflector 257x)

Unexpectedly, the small, strongly condensed object was still visible.

93P/Lovas 1

Jan. 4   13.3 mag   Dia. 0.8'   DC 4-5   (40.0-cm reflector 144x)

Still bright and easy to see.

110P/Hartley 3

Jan. 4   14.5 mag   Dia. 0.5'   DC 6   (40.0-cm reflector 257x)

Strongly condensed.

192P/Shoemaker-Levy 1

Jan. 4   13.4 mag   Dia. 0.6'   DC 4   (40.0-cm reflector 144x)

Unexpectedly bright and visible visually.

* 2008 Jan. 2 (2 comets)

I observed 8P/Tuttle and 17P/Holmes on Jan. 2 beside Tsurumi River in Yokohama City, Kanagawa, Japan.

The weather was fine with no clouds, but the sky was not excellent. Comet Holmes is near limit to see in the city light pollution without an excellent clear sky.

8P/Tuttle

5.5 mag   Dia. 18'   DC 3-4   (10x66 monocular 10x)

17P/Holmes

4.0 mag   Dia. about 55'   DC 1   (10x66 monocular 10x)

* 2008 Jan. 1 (2 comets)

A happy new year! Here are my first observations in 2008.

I observed 8P/Tuttle and 17P/Holmes on Jan. 1 beside Tsurumi River in Yokohama City, Kanagawa, Japan.

It was fine with no clouds at dawn, and I enjoyed the very beautifull first sunrise in 2008. However, heavy clouds covered the sky in the afternoon. The weather became fine at night, but small clouds still remained and passed over the sky frequently. But the sky was clear and the comets were visible better than last night.

8P/Tuttle

5.6 mag   Dia. 19'   DC 4   (10x66 monocular 10x)

17P/Holmes

3.7 mag   Dia. 52'   DC 2   (10x66 monocular 10x)

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Go to Seiichi Yoshida's Diary of Comet Observations in 2007.

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