本帖最后由 cosmosEX 于 2014-11-8 13:23 编辑
没在好环境下用过大口径，但是目视能看到尘埃带的报告确实有很多。
以下为例：
Observation Poster: Ben Waranowitz <bekirwicz@yahoo.com>Observer: Ben Waranowitz
Your skills: Intermediate (some years)
Date/time of observation: Early 1960s
Location of site: Queens, New York City (Lat 40*44', Elev 10m.)
Site classification: Exurban
Sky darkness: 5.5 <Limiting magnitude>
Seeing: 8 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 60mm f/15 altazimuth Unitron
Magnification: 36x, 50x
Filter(s): None
Object(s): M31 M32 NGC205 (M110)
Category: External galaxy. Group of galaxies.
Class:
Constellation: AND
Data: mag 8.5 size 17' x 10'
Position: RA 00:40 DEC +41:41
Description:I was learning the sky from my parents' backyard in Queens NY near the borderof Nassau county. Queens Village / Elmont NY. It was a dark night and no onehad floodlights in their backyard then. No shopping mall parking lots lit 24/7!My eyes were about 20 years old, not 63 with retinal problems, lens implant andcataract. I located M31 and M32 with my 60mm f/15 Unitron and a 25mm eyepiece.The sky background was dark. I only saw the brighter central region of M31, butcould plainly detect the dust lane. M32 wasa bright fuzzy. I used a Unitron'Hexagon' rotating eyepiece holder with a 1.25 in. Jaegers 30mm f.l. eyepieceand all my .965-in. eyepieces in steps: 25 18, 12, 9, 6, down to 4mm. The slowmotion adjustments on its sturdy altazimuth mount were adequate. I bumped offof M31 and found a faint fuzzy. I got all excited as I thought I had found acomet. I made mental notes to the locations of M31 and M32 so I could locateit again, then went inside to check Norton's Star Atlas, epoch 1950. This wasNGC205! I couldn't believe that a 60mm would show this but it plainly did.I can not see M32 nor M110 from Nashville, Tennessee with a 5 inch SCT!This is a very dated observation but my memory of that night is clear.
也就是说5.5的环境下用60mm镜子足够看到M31尘埃带，换成8寸效果肯定更上一层楼
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噢，这样啊，呵呵，我属于基本不目视的人，这回学习了
显身卡
，换成150口径以上目视效果图好些