三角座M33——可以挑战一下视觉的星系（组图）
据说这家伙曾经被人用裸眼看到过……M33:三角座内的螺旋星系
影像版权与提供: Robert Gendler
说明: 影像中这个面对着我们的壮丽螺旋星系M33，位在北天的三角座 (Triangulum)内，它更著名的名字是风车星系(Pinwheel Galaxy)或简称为三角座星系。 M33的直径超过五万光年，是本星系群里的第三大星系，只输给仙女座星系(M31)和我们的银河系。 M33距离银河系约有三百万光年，位置很靠近仙女座星系，在这两个星系的观星人，彼此都可以看见天空上有个非常壮观的螺旋星系。 而从地球看出去，这幅由27张照片拼凑出来的极清晰M33马赛克影像，美妙地呈现出星系松散漩涡臂上的蓝色星系团和粉红色恒星形成区。 其中洞穴状的NGC 604，是从星系中心向右上方伸展之漩涡臂上最明亮的恒星形成区。 像M31一样，M33众多已经经过精确量测的变星，让这个邻近的螺旋星系成为一个测定宇宙距离尺度的宇宙量天尺。
图文来源：http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/ap030924.html
基本数据：
天体名称:M 33（NGC598）
俗名:Pinwheel Galaxy
天体类型:星系
星等:5.5
大小:68.7'x41.6'
方位角:23°
分类:Sc
备注:Triangulum galaxy
数据来源：sky map 10
http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/image/0309/M33colormosaic5LL_gendler_full.jpg
[ 本帖最后由 Eldghost 于 2007-6-12 23:10 编辑 ]
附近的螺旋星系 M33
影像提供 & 版权: T. A. Rector & M. Hanna, NOAO, AURA, NSF说明 : 螺旋星系 M33 是我们本星系群的中号成员，M33因它所在的星座 位置所以也被称为三角星系。 M33 (的半径) 虽比我们银河系与仙女座星系 (M31)小上四倍，比起许多附近区域的 矮椭圆星系则大多了。 M33与M31 的靠近使得部分人士认为前者是较具份量的后者的卫星星系。而M33与我们银河系的接近，使得它在天空占住 2 倍满月视角的大小，用副好的双筒望远镜就看得到。 上面的高分辨率影像 是从凯克(Kitt Peak) 国家天文台的0.9 米望远镜所拍下的四色合成图。
来源：http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/ap021202.html
The Triangulum Galaxy - M33
ST-10XME and CFW8a, Astrodon LRGB filter setTakahashi FSQ F/5 Fluorite Refractor w Robofocus
20 x 3 min Luminance, 8 x 5 min RGB for a total of 3 hours
Self-guided on an AP900QMD mount
Acquired, Flats and Darks subtracted in CCDSoft5
Alignment and Sigma Reject combine in Maxim
Levels and curves in PS CS2
Sharpening via High Pass filter on the Luminance in PS CS2
Luminance layered in per Rob Gendler's article
No noise reduction
RA: 1h 33.9
Dec: 30:39
Visual Mag: 5.7
73 x 45 arcminutes
Click on the image to see it at 2x this size.
===============
From SEDS.ORG:
Probably discovered by Hodierna before 1654. Independently discovered by Charles Messier
1764.
The Triangulum galaxy M33 is another prominent member of the Local Group of galaxies. This
galaxy is small compared to its big apparent neighbor, the Andromeda galaxy M31, and to our
Milky Way galaxy, but this is more of an average size for spiral galaxies in the universe.
One of the small Local Group member galaxies, LGS 3, is possibly a satellite of M33, which
itself may be a remote but gravitationally bound companion of the Andromeda galaxy M31.
M33 is approaching us (our Solar System) at 182 km/s. Corrected for our motion around the
Milky Way's Galactic Center, it is approaching our Galaxy at 24 km/sec.
M33 was among the first "spiral Nebulae" identified as such by William Parsons, the Third
Earl of Rosse. It was also among the first "nebulae" identified as galaxies, in which
Cepheid variable stars were found; Edwin Hubble published a fundamental study in 1926
(Hubble 1926).
The results of the Hipparcos satellite have lead to a revision of the cosmic distance
scale, therefore also of our distance to M33: The current value is about 3.0 million light
-years. With this value, its angular dimension of 73 arc minutes in major axis (about 2.5
times the Moon's diameter) corresponds to about 50,000 light-years, half the diameter of
the Milky Way. However, the faintest outlayers seem to reach more far out, so that the true
diameter may be at least 60,000 light-years. The mass of the Triangulum Galaxy has been
estimated between 10 and 40 billion solar masses.
For the observer, this galaxy can be glanced with the naked eye under exceptionally good
conditions; for most people, it is the most distant object visible to the naked eye. It is
outstanding in good binoculars, but as its considerable total brightness is distributed
quite evenly over an area of nearly four times that covered by the full Moon, its surface
brightness is extremely low. Therefore, it is difficult to impossible to view this galaxy
in telescopes which do not allow low magnification - lowest is best for this object ! M33
is also a most rewarding target for the astrophotographer, who can track down its spiral
arms and brighter nebulae with considerably inexpensive equipment.
===============
Flesherton, Ontario
August 20 2006
图文来源：http://www.astrofoto.ca/stuartheggie/ccd_photos/M33_LRGB_FSQ.html
这张是1600*1200的尺寸
Telescope: Luminance: Takahashi FS-128 apochromatic refractor, 1040 mm, F/8. RGB: Borg apochromaric refractor 125 mm F/6.4CCD Camera: Luminance: SBIG ST10-XME / CFW-8. RGB: FLI CM2-1
Mount: German equatorial mount Astro-Physics GE 600 GTO
Integration: Luminance: Core 16x5 minutes bin 1; arms and background: 4 frame mosaic of 6x5 minutes bin 1. RGB: 12:12:12 minutes taken and processed by Giovanni Paglioli (Salerno)
Date / Location: August 12 2004 - Sicily, Mt. Etna North, 1500 m. s.l., medium seeing condition, wind. August 17 2004 - Sicily, Loc. Morra - Assoro (EN), 450 m. s.l. good seeing condition.
Software: CCDSoft, MaxIm-DL, PhotoShop
Publications: Nuovo Orione July 2005
Anacortes Photo of the Day 19 December 2004
RAI Educational 2 / RAI 3 Nazionale 22 September 2005, "A scuola di stelle"
Nuovo Orione Calendar September 2006
http://www.astrogb.com/hires/M33h.htm 图片来源：
http://spiff.rit.edu/classes/phys230/lectures/local_group/m33_color_mosaic_rot.jpg
最后一张位置示意图！
图片来源：http://www.lasam.ca/messier/M033.JPG 酷图啊,壮观,!!::25:: LZ强悍!为什么不翻译下呢?::21:: 我们水平有限，不如您帮翻译一下？ ::27:: ::27:: 不错。像花一样 楼主图已经成为今天流行的发图范式，堪称经典前辈啊 超级漂亮啊啊啊啊啊 似乎尘埃很少 漂亮？顺便问一下，是谁用裸眼看到？视力不会5.4了吧 这样美丽的照片只能是高级设备摄影而得到的，目视是看不到的，我从来没有看到深空的星云和星系，只看到过几个星团，时隐时现的，也不怎么爽。 欣赏了::070821_09.jpg:: 确实是一个视觉享受 宇宙真是太美了！看这些照片能够感受到人的渺小 哪位翻译一下，我来加分 忒难翻译了吧！::070821_09.jpg::::070821_09.jpg::::070821_09.jpg::有些词电脑都查不出是啥意思。。。
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