suhuasky

Comet 17P Holmes, a very obscure and dim object to say the least only 30 hours
ago, is
blazing away at a brightness increase rarely seen before in such a short period
of time,
rising more than 15-16 magnitudes since October 23. Now at brightness 2.0 (ASO,
Oct. 25
UT, 04:10) and perhaps still brightening, this comet must be watched
continuously for
the next several weeks.

It appears as you seen in the first light photo from ASO; this is an RGB color
image
from an ST 401-ME camera, 12 second images in each color and combined. No post
processing, just a raw image, showing the brilliant round yellow-green huge
(nearly 3
arc minutes across) coma. The very high contrast negative imaging reveals a
possible
dust tail coming nearly due north (down) from the comet as well as one streaming
from
the south side of the coma. The image was taken with a 0.4m SCT at f/3 at the
observatory (Harvard MPC H45) at Petit Jean Mountain in Arkansas.

This unusual "round comet" to be so bright without a tail or irregularity is
something
very extraordinary. The comet can easily be seen with the naked eye, but even
binoculars and telescopes give the impression that the viewer is peering at a
very
bright star.

The field of view in both ASO images is 12 arc ' by 7' with SOUTH up.

For those with no image attached, please visit the report with both color and
high
contrast negative (showing possible dispersion from the coma), at the Arkansas
Sky
Observatory (ASO) website under the "ASO News Links" on the home page at:
http://www.arksky.org/

suhuasky

Hello Everyone,

I just went outside from Draper, Utah at 06 UTC on
October 25, 2007. The comet looks great. I think the
magnitude is closer to 2.2 by comparing with the stars
in Cassiopeia. I hope I'm correct.

Thanks for making this observation possible.

Michael

不得了啦
快到2等了

suhuasky

We have detected brightening here (H45, Petit Jean Mountain in Arkansas, USA)
from about 2.3 (CCD)
to between 2.1 and 2.0 to this time (04:10 UT, Oct. 25). Coma is huge, some
161" arc and nearly
perfectly symmetrical with some indication of scattering due north of center.
Color imaging,
indexed on three G-class stars is indicating a very yellow-green comet, contrary
to some reports of
reddish appearances; curiously the comet does appear somewhat red to the naked
eye.

Our image will be posted shortly.

Clay

Nonstop

今晚就去看！！！
希望还能看到

福建ltycho

好消息！！！

suhuasky

继续再上照片
唉
还要凑字才能发布

福建ltycho

如果有尾巴就壮观的大了！
苏兄字数不够可以发表情，哈哈

yanbinemail

我在yahoo论坛的内容
Just came back from outside. the 17p is as bright as a new bright star
in Per. Naked eye easily find it in the night sky. The constellation
of Perseus changes her figure and I was not able to recognize it at
the beginning!

Observation made just a few minutes ago on Oct 25, 5:10 to 6:15 UT.
Clear sky with almost full moon. Naked eye visibility 4m if away from
the bright moon. To a naked eye, 17p looks like a 2.5 magnitude new
star. Using 6cm retractor, total brightness comparison gives magnitude
2.0 to 1.9. at 76x, the nearly round shape coma measures about 62" by
58" with DC=9. The coma is very bright, easy to distinguish even from
not-so-dark background. Both coma and false nucleus are yellow to
orange color, but my photo shows green halo also. The coma is slightly
elongated in a north-south direction. The false nucleus is 10" by 6",
easily distinct out of coma by its brightness and sharp border. The
nucleus is very dense, stay in the center of the coma (may be off a
little bit) with also elongated in a north-south direction, no tail.

David Z Young
Brenham, TX, USA.
如果猛然看英仙座，我竟然会认不出来，因为它的形状变了，多了一颗星！
我的估计有2等。

北斗流星月

该加高亮

andy2000a

看得到尾巴嗎

否則如果看起來很亮  感覺不太出是彗星

大角星

我们拍到了，具体见：
http://www.astronomy.com.cn/bbs/thread-81109-1-1.html

活动星图

没有彗尾、彗发的结构，完全是点状光源

福建ltycho

经天图

2007-10-25 17:51

Alone狼

没尾巴的看起来不爽~

Sunjune

w我们又有看头了。。。又有彗星来了

BA2CR

刚观测完，亮度约2.5等，我认为有彗发，只不过彗发高度凝结，因为用望远镜观测，在彗核周围有朦胧状物。

沈阳-陈博丹

原帖由 Sunjune 于 2007-10-25 18:43 发表
w我们又有看头了。。。又有彗星来了

有大DOB的好处体现出来了……

suhuasky

彗发是慢慢扩散出来的
彗星又比较远，形成一定直径的彗发需要时间，往后凝聚度会逐渐降低，彗发扩散，至于尾，我估计有点困难
彗星亮度剧增13等，这么强烈的爆发，看来彗星上出现了不可思议的灾难，是什么呢？呵呵，未解之迷
从目前的亮度。日彗、地彗距离粗略推算，彗星的绝对星等达到－2等以上，超过了海尔－波普，奇迹。

[ 本帖最后由 suhuasky 于 2007-10-25 21:43 编辑 ]

creeperr

这该天杀的雾

sagalliant

呵呵，肉眼看到了............