看看这个Celestron超级天体照相仪和超级价格。
Product Description:Observatory-class optics
Celestron’s 20-inch, f/6.8 field-corrected, modified Dall-Kirkham telescope is for the professional's professional. It features stellar-quality optics topped off with a mount that's second to none.
Revolutionary Optical System
Celestron’s Dall-Kirkham telescope is near optical perfection, exceeding off-axis performance of even the Ritchey-Chretien design. RMS spot sizes at the edge of a 35mm frame remain smaller than a single pixel on the most advanced CCD cameras available to amateurs today. You'll get star points, not blurs or cones, across the full field of view.
The optical system also features a conical primary mirror with low thermal mass and three cooling fans to minimize the cool-down time. Celestron's no-compromise design provides the superb resolving power Dall- Kirkham telescopes are known for, but without the coma that has previously limited their wide-field performance.
XLT coatings
Celestron's XLT coating process uses state-of-the-art, thin-film, vacuum-deposition technology. To ensure consistent optical coatings of the highest quality the process is tightly monitored and controlled by highly trained technicians. Prior to coating, each optical element is thoroughly cleaned and inspected to ensure proper adhesion of the films during the coating process. Materials used in our reflective and anti-reflective coatings, including aluminum, hafnium oxide, titanium dioxide, silicon dioxide, and magnesium fluoride are the purest available, exceeding 99.99 percent. The result is image clarity so stunning it must be seen to be believed.
Astrograph mount
The C20 comes with a professional-class, portable pier mount. The C20 Astrograph mount breaks down into three components for easier transporting and includes fully integrated electronics as well as Celestron’s renowned and proven NexStar® software. Tracking accuracy with this mount is better than 5 arc seconds peak to valley without enabling the PEC function.
The C20 is the most sophisticated telescope Celestron has ever designed and manufactured. The C20 is a system that meets the highest standards Celestron sets for technical innovation, design and engineering superiority, precision performance, and uncompromising optical quality. And it'll provide superb performance for a lifetime-plus.
Product Attributes:
Focal Length 3454 mm
Focal Ratio f/6.8
Goto Yes
Lens Coating StarBright XLT
Mount GermanEquatorial
Objective 508 mm
Product Weight 280 lbs.
Type Corrected Dall-Kirkham
User Level Advanced
:shock: $39900.00
280 lbs.合127kg，估计也不会有人扛着去野外摄星。等我有了天文台，就来一个~
http://www.binoculars.com/products/Celestron_C20_Astrograph_Dall-Kirkham_Telescope_-_With_Portable_Pier_Mount_32351.html 东西是不错,只是这价格.......... 拿来拍行星不错。
Re: 看看这个Celestron超级天体照相仪和超级价格。
...Revolutionary Optical System
Celestron’s Dall-Kirkham telescope is near optical perfection, exceeding off-axis performance of even the Ritchey-Chretien design. RMS spot sizes at the edge of a 35mm frame remain smaller than a single pixel on the most advanced CCD cameras available to amateurs today. You'll get star points, not blurs or cones, across the full field of view.
...
不明白，为啥说这个DK镜的离轴表现比RC好呢？ 呵呵~~~dk应该不如rc 看楼上的目镜规格, 不如把Nagler16和7出了, 搞一套UO的Or划算, TV的PL也行. 为什么说出nagler16。7呢？个人感觉nagler还不错
请楼上细细道来。。 :shock: 以后再有人问我中了大奖首先要干什么。
我会答到，一不换肾，二不换老婆，先买这台镜子 为什么说出nagler16。7呢？个人感觉nagler还不错
请楼上细细道来。。 :shock:
没有注意你的主镜是短焦快速的TV76, 我个人认为长焦段有个Nagler T5/26足矣，中短焦端搞几个简单结构的优质经典目镜，例如TV的PL和UO的HD Or，便于发挥你的镜子性能，尤其是高倍端，用复杂结构的Nagler 精度和反差都比较逊色的。
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