打算买第二个镜子，都来给点意见吧
去年不太懂，匆忙买了个MaxVision，80/900。现在想买个Dobs，看中了Orion的一款8"（再大就不方便搬移了），带电子导星系统，价格多了$200。http://www.optcorp.com/images2/4295-L.JPG
不知道有没有人用过。主要想知道这种寻星系统效果如何，能不能用于跟踪摄影？
请大家给点意见。我也再多了解一下。 我还以为价格是$200, 吓一跳!
没觉得你的第一个镜子买失败了,我觉得还不错,长焦折射,比较适合新鸟 口径太小，色差大，城市周围光害严重，看不到多少东西。赤道仪可能不是原厂货（说明书却是Mystery，错漏百出），定位对焦都很难，所以打算走第二步。
摄影倒不急，如果可以很好地跟踪，就想试一下长时间曝光摄影。
价格$500左右。
PS: 主要是为了将儿子培养成天文爱好者。小口径长焦折射镜视场小而且暗，所以决定买dobs。至于以后是不是有第三步，只好走着瞧吧。
[ 本帖最后由 bluetango 于 2007-6-21 02:23 编辑 ] $500的镜子(不管折射还是DOB)可能达不到你的心理预期.
先要想清楚心理预期,到底想看到什么样的东西,客观考虑价格与心理预期的问题
就象有的人缺乏基本天文观测常识和经验, 提出类似于"买一个能看见乒乓球大小的木星的镜子要多少钱"的问题
一个最差的80ED折射单镜筒也不止$500了,别以为你的$500的8寸DOB能看到多少好东西,虽然口径大,不然大家都去买这个DOB了
另外,想搞深空摄影, 别说$500, $5000的装备也都是"一般水平"
[ 本帖最后由 张瀚 于 2007-6-21 18:53 编辑 ] 我的第一个镜子（9mm、25mm目镜）看到了土星光环，勉强看到了木星条纹，看m13就只有一团雾。最主要的问题是目标太暗，寻星困难，期望大口径能解决这一点。目前的预期就是看一遍梅西耶天体（现在只能看到M13以上几个大的天体）。我在温哥华，天气和天空条件不太好，这里的爱好者有一半是用Dobs。我也问过他们重新镀膜的问题，都说十多年没问题。
摄影方面是因为打算买个Canon EOS400D，所以想在买镜子的时候一并考虑，至于是否深入，要看能走多远了。最理想的当然是ED加CCD了。
谢谢张瀚 ~ 走出市区的繁华和灯光，去郊外领略星空的壮丽和璀璨吧! 有时候一个好镜子比不上一个好的观测环境
good luck 据说orion只在北美销售不知是否真实 我用Orion的XT１０i 快半年了， 比较满意， 之前我一直是玩折射镜的。 现在加上一个跟踪平台， 更是如虎添翼， 在３００倍的情况下也不用每３０秒去动一下望远镜了。
下面是我刚刚拿到XT１０i时候在CN上发的评测。 当时肯定是有点兴奋了， 后来的使用中， 也有了新的感触， 不过总的来说还是物超所值的。
Being a refractor guy, I'd say I was really impressed with what I saw last night.
I asked some questions about what is the best complementary scope for my 5" refractor on the forums some time ago. I went to star parties to observe and gathered suggestion from the experienced, too. I finally joined with an Orion XT10 intelliscope due to the very convenience of a dropby at the local orion store in Cupertino, CA, where I can check the scope before I buy.
Collimation is no problem as I have laser collimator for rough collimation and Catseye tool set for fine collimation. The collimation was pretty close to perfection according to the auto-collimator before I moved the scope outside the room. At 10:00 pm, I set up the scope in a badly light-polluted patio. Even without a telrad, the stock RACI finder did a decent job to find the object, thanks to some skills I learned from the star parties. Sirius was the first victim , and unsurprisingly I saw so called annoying spikes. But I thought the opposite and found the spikes were actually aesthetically "good-looking" since I've learned to live with that after viewing so many terrific astrophotos taken by scopes with spikes, such as HST. Sirius looked kinda loose compared to the embedded memory I have from viewing it through my Tak FS128. M42 got the second view as it would soon disappear behind a tall building. I was not surprised to see a well resolved nebula, as I did a couple of times on the star parties with the same type of scope. A quick check on Trapezium with nagler 9mm T6 at 133x revealed that the seeing was not bad even if the mirror was still warm, because I could catch a glimpse of the F star, while E star was a piece of cake.
The unexpectedly view of Trapezium F star had me thinking of viewing Saturn regardless of the still hot mirror. I quickly centered Saturn in the nagler zoom 3-6mm EP and recalled what some experienced observers said about the mechanics of this type of Dobs. To foucs at above 200X and keep centering the object was really a challenge for me, since I've been spoiled by the tracking capability of the GEM mounts in the past 2 years. As a side note, the new Crayford style focuser which is similar to what is found on the Orion ED series refrector is really nice, although I was a bit spoiled by the moonlite focuser and FT focuser I've used before. After fiddling with the focuser at high mags, I quickly found that the "best view region" in the EP was rather narror where Saturn looked really sharp as long as the air became steady. I recalled that many reflector users mentioned that for such a fast newt scope (f/4.7), the "diffraction limited region" is rather small. I suspect what I saw echoed with what I read on the forums. As the mirror cooled down (with a fan blowing air) after about 45 minutes, I caught some really sharp views of Saturn at 300X in the center 20 degree region through the nagler zoom 3-6mm. Cassini division, C ring and the belts on the surfact, even the shadow of the ring were really sharp. I knew what I would expect from a 5" refractor under most common seeing conditions, however, I was really impressed by the view from a 10" newt which I bought for viewing DSOs. I spent almost one hour viewing Saturn, learning to nudge the Dob at the high mag. I remember in a recent thread on the forum, people have been discussing if a fast newt can deliver decent planetary view. Now I totally believe what those mirror gurus say about that.
To confirm the thought on "best view region", I targeted Procyon that was fairly high in the sky. At 300X through the nagler zoom EP set at 4mm, I found the diffracted star image looked really good within the central 30% of the field of view, which corresponds about 15 degrees. The intra-focus and extra-focus images looked almost the same, without signs of turned edge or apparent zones. When the star image lied in the center of the FOV, the concentric rings were really nice, thanks to the very good collimation and the steady air. As the image drifted towards the edge of the FOV, I could see squeezed rings at one side, which indicates the coma became really bad. Note that I am no optical expert and the test was also brief. I think I'll do a more thorough test tonight when an excellent seeing is highly possible. Since undercorrection is a common problem in this type of Dobs, I'll mainly focus on checking SA.
As time passed midnight, I got no time for a thorough test of the "push-to" function. I then packed up and went back to the room, sitting there and enjoying the wonderful views of Saturn in my head.
I was very happy with the XT10i's debut last night, and I found that
1). The optics are really good
2). Excellent seeing and accurate collimation are the major factors that determine the sharp views of Saturn
3). XT10i is really fast, even my plossl-like nagler zoom EP performs poorly at the edge
4). A fast newt can deliver decent planetary view as long as 1)~3) are satisfied
5). Most importantly, "Aperture Rules!!". I've been viewing Saturn using 5 different scopes, including a 5" apo, a 5" achro, a 6" mark-newt, 8" newt and XT10i. XT10i is the winner, or I should say it has the most potential to deliver the best view given the right conditions.
6). I become a mirror lover
I'm a little concerned on the "diffraction limited region" as I mentioned above. Can anyone guide me to a thread or some link which tells how to calculate the size the of region (actually size and FOV in a EP) for a newt of any f ratio? I have read some and just cannot find them since the searching fucntion is under recovery. Or maybe a simple answer for "Is what I found normal?" is better.
Thanks! 有时候一个好镜子比不上一个好的观测环境
没办法，光害很大程度削弱了器材的能力。现在要看到美丽的星空，至少得开出3小时。一年中也没有几次理想天气。 现在加上一个跟踪平台， 更是如虎添翼
今天去看了，Orion 的这种寻星系统不是用来跟踪的，也不是电动马达自动定向，只是用显示方位差的方法导引操作指向天体。对跟踪也有一定帮助，但仍然是手动的。
10"的镜子当然效果好很多。我先试一下不要辅助定位和跟踪是否足够。 总的来说，dob确实是高性价比的选择。 wbhifi兄的评测写得很好阿 呵呵，好文，评测写的充满激情！
其实国产镜子现在越来越好了．我当初出TV-102就是因为找到朋友一个丢阳台上风吹雨打若干年的国产114牛反．后来他买了个Orion８寸牛反，又让我有了出C9.25之心．．．
镜子太大抬不动，买ＡＰＯ镜看行星，手推望远镜来跟踪，人生三大自虐方式也．．． “手推望远镜来跟踪”
我就是这么自虐的::40:: 原帖由 bluetango 于 2007-6-22 08:03 发表 http://www.astronomy.com.cn/bbs/images/common/back.gif
今天去看了，Orion 的这种寻星系统不是用来跟踪的，也不是电动马达自动定向，只是用显示方位差的方法导引操作指向天体。对跟踪也有一定帮助，但仍然是手动的。
10"的镜子当然效果好很多。我先试一下不要辅助定位和跟踪是否 ...
所谓的跟踪平台是指这个东西：::33::
http://www.roundtableplatforms.com/ 原帖由 过马路 于 2007-6-22 09:04 发表 http://www.astronomy.com.cn/bbs/images/common/back.gif
镜子太大抬不动，买ＡＰＯ镜看行星，手推望远镜来跟踪，人生三大自虐方式也．．．
花很多米， 一年就用那么几次， 也是一大自虐，::42:: 所谓的跟踪平台是指这个东西
这样啊~~那我还是先自虐一段时间吧::42:: 原帖由 wbhifi 于 2007-6-22 10:55 发表 http://www.astronomy.com.cn/bbs/images/common/back.gif
所谓的跟踪平台是指这个东西：::33::
http://www.roundtableplatforms.com/
这个装置貌似还有更好的，具体什么牌子我倒是给忘了，但是这个东西可以用来摄影，呵呵~相比是不错的。 昨天去店子了，Orion IntelliScope XT8没货，没法试效果，就扛回了Skywatcher 10"+28mm 2"，刚才去外面试镜，看木星效果不错。
第一次用Dobs，感觉找星很难，M81和M13都没找到。梅西耶天体在寻星镜里看不到，只能参考其它亮星，由于没有微调装置，很难把握移动角度。
因此犹豫是不是该换带导星的，虽然是简易的，总比没有要好，用laser pointer似乎也不太方便。
各位喜欢牛反的朋友介绍一下高招，怎样做才能方便地找到目标。如果大家都是靠经验和耐心，我就不换了。
[ 本帖最后由 bluetango 于 2007-6-23 01:45 编辑 ] 请 wbhifi 说说对Orion XT10i 的电脑定位功能的感觉，我想知道是不是很爽~
刚浏览了IntelliScope™ Computerized Object Locator 的说明书 http://www.optcorp.com/pdf/OrionManuals/intelliscopecontroller.pdf ，觉得如果名副其实设计到位，这几个功能是挺有用的：
1、可以定位NGC天体，一般而言这比Messier要难一些；
2、可以浏览天区，看到自己感兴趣的东西的时候可以根据坐标查找资料；
3、方便寻找土星以外的行星；
4、操控机构有了改进，应该比一般结构稳定。
没弄明白是不是两星定位以后要立即观察目标，因为看起来系统内部并没有时间/地理位置的设定和跟踪，那么每次观测都需要重新定位了。明天再细读一下。熟悉或有兴趣的朋友可以说说。
[ 本帖最后由 bluetango 于 2007-6-23 03:57 编辑 ]
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