通过矫正镜破裂的8寸LX90所拍摄的衍射图案
Hadar星（半人马座beta星），已经不是一个完美的点状了
矫正镜碎裂的8寸LX90所带来的土星，好像在被黑洞吞噬。。。
现在，换我们的男主角出场～
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Did you ever try to break your scope before? I doubt you dare. I maybe the first LX90AT user with the cracked corrector plate.
Here the story begins.
If anyone remembered my previous post about disassembling the LX90AT, you should know why I removed the corrector plate. Yes, I dropped a toothpick into the OTA from the visual back. All of the nightmare started from here. I bought a Purosol Optical (PO below) and their microfiber cloth as I planned to clean the corrector plate. In the end, I cleaned the primary mirror as well because the PO claimed that the solution was enzyme based and would not hurt the coating. That’s true, just that the microfiber cloth left quite a lot of fiber behind.
Continue reading ‘LX90的矫正镜破碎了’
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什么是伽利略望远镜？为了庆祝2009国际天文年, 一队顶尖的天文学家、光学工程师和科学教育学者主导了价廉物美的望远镜套件。只要15美金，你就能够拥有比伽利略·伽利雷在1609当年所使用还好的望远镜。
If you’re a computer enthusiast, you must be familiar with the benchmark score obtained from 3dMarks, PC Mark, Everest, PCMark, Prime 95 and so on. Is there anything similar to represent the performance of telescope? Well, there’s is and someone did it in the form of scores too.
Credits to Mr.Yoshida Hiroshi, he has done a review on 75 telescopes. He reviewed them visually and scored them. The photographic performance of the telescope is not taken into account. I would say this is just a reference for you but not solely the factor to consider a telescope.
Before buying a telescope, I suggest you read through the reviews posted at forums like cloudynights.com and most importantly, join a stargazing session with someone who already owned a telescope. You will know better what to expect.
Here you read the rankings, cz-telesco.bbs.coocan.jp
The content is in Japanese, you can use Google translator to translate into English or any other language you prefer.
Image shift and mirror flop are the common phenomena seen on mirror type telescope, especially SCT. When either of them happens, you can see the image through the eyepiece shifting. The reason for these phenomena is the not-so-perfect movement (slightly to left or right) of the mirror. What’s the difference between them?
While focusing, “Image Shift”.
While slewing, “Mirror Flop”.
Both are actually the same thing. When focusing, you are doing the shift of the mirror back and forth, thus you made the imperfect movement and the movement caused the image shift; when slewing, gravity is doing it and it causes the mirror flop.
Before anything starts, I want to explain AA. AA is my own abbreviation, it’s Amateur Astronomer in full.
What’s the common requirement of an AA’s scope? Unless you are a serious AA with deep pocket, you won’t have an observatory that allows you to mount a gigantic telescope inside. Some AA travels to the dark site with his scope or just move his scope from his house to the backyard. It can’t be too heavy. So, portability comes into one of the major considerations. We want to get the largest aperture within the portability.
8″ SCT has it all. For example, my fork mounted LX90 has an aperture of 203.2mm, 2000mm focal length and weights about 24kg. I can carry it around easily. (Not for a marathorn though)
Left: 8″ LX90 of Erwin Kats from Netherlands.
Continue reading ’8″ SCT The Best?’
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