观测DSO的细节

“狩猎难以捉摸的猎物”

部分梅西耶星系可以看得到旋臂的，比如M31 33 51 101。NGC星系中也可以找到很多。

要观测旋臂，需要注意几点：

1.优秀的环境+视力暗适应

2.大口径望远镜。但是不要因为你的望远镜是中等口径就放弃了寻找的机会。

3.增加观察时间。看得越久，看的越多。

4.一些观察者喜欢首先观看物体的照片。确切地知道在哪里寻找星系的微弱成分非常有帮助。当然，危险在于想象您看到某物只是因为您知道它在那里。我宁愿在注意到这些微弱的功能后，再检查照片以确认确实存在。

文章中列出的几个可能看得到旋臂的NGC星系如下。

Object	Constellation	SurfaceBrightness	Mag(v)	Size/Sep	PA (°)	Distance(million l-y)	RA	Dec.
NGC 3310	UMa	12.8	10.8	3.1′ × 2.4′	156	50	10h 38.8m	+53° 30′
NGC 3521	Leo	13.3	9.0	11.0′ × 5.5′	163	32	11h 05.8m	–00° 02′
NGC 3631	UMa	13.4	10.4	5.0′ × 3.7′	114	59	11h 21.0m	+53° 10′
NGC 3893	UMa	13.1	10.5	4.5′ × 2.8′	165	49	11h 48.6m	+48° 43′
NGC 3938	UMa	13.8	10.4	5.4′ × 4.9′	0	41	11h 52.8m	+44° 07′
NGC 4030	Vir	13.2	10.6	4.2′ × 3.0′	27	65	12h 00.4m	–01° 06′
NGC 4051	UMa	13.3	10.2	5.2′ × 3.9′	135	36	12h 03.2m	+44° 32′
NGC 4414	Com	12.8	10.1	4.4′ × 3.0′	155	35	12h 26.5m	+31° 13′
NGC 4651	Com	13.2	10.8	4.0′ × 2.6′	80	35–75	12h 43.7m	+16° 24′
NGC 4725	Com	14.0	9.4	10.7′ × 7.6′	35	58	12h 50.4m	+25° 30′
NGC 5147	Vir	12.8	11.8	1.9′ × 1.5′	120	50	13h 26.3m	+02° 06′
NGC 5248	Boo	13.8	10.3	6.2′ × 4.5′	122	54	13h 37.5m	+08° 53′
NGC 5595	Lib	12.9	12.0	2.2′ × 1.2′	50	127	14h 24.2m	–16° 43′
NGC 5597	Lib	13.3	12.0	2.1′ × 1.7′	95	126	14h 24.5m	–16° 46′
NGC 6384	Oph	13.8	10.4	6.2′ × 4.1′	30	86	17h 32.4m	+07° 04′

Sky_amp_Telescope__June_2019.pdf

---

20寸望远镜的观测

[直接观察到的旋臂]

M51
M65
M66
M81
M90
M94
M95
M96
M99
M100
M101
M106
M109
NGC2403
NGC2903
NGC3184
NGC3628
NGC3631
NGC3726
NGC3728 - given as Mag 14+ in sky safari, but it turns out that its Mag 10+ in Ha
NGC3893
NGC3896
NGC3953
NGC4278
NGC4449
NGC4559
NGC4565
NGC5248
NGC5371

[直接或隐蔽可见的]

M61
M64
M82
M88
M91
M98
M104
NGC2537
NGC2681
NGC2768
NGC3294
NGC3344
NGC3373
NGC3596
NGC3646
NGC3675
NGC3686
NGC3718
NGC3729
NGC3813
NGC3938
NGC3945
NGC4013
NGC4051
NGC4214
NGC4216
NGC4293
NGC4389
NGC4490
NGC4517
NGC4535
NGC4536
NGC4618
NGC4625
NGC4725
NGC4762
NGC5005
NGC5364
NGC5383
NGC5746
NGC5907