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quantumkit
週三 02 6月, 2010 11:54
版面: 天文話題 Everything about Astronomy
主題: 可以計算出兩恆星間角度的工具
回覆: 6
觀看: 2818

Re: 可以計算出兩恆星間角度的工具

leungchun 寫:我想找一個可以計算出兩恆星間角度的工具。

貌似http://www.wolframalpha.com可以做到,但我又不知如何使用。
Just type in
"angle between vega and altair",

and it will show you the results~~

http://www.wolframalpha.com/input/?i=an ... and+altair

[爽]
quantumkit
週一 10 5月, 2010 10:26
版面: 天文話題 Everything about Astronomy
主題: A visit to OPT
回覆: 1
觀看: 2365

A visit to OPT

今日無聊揸車去左半個鐘頭之外O既Oceanside...當然要到一到傳說中O既Oceanside Photo and Telescope

入面當然係"毒氣室", 大概有六七十枝set 好左O既鏡, 主要有 celestron, vixen 同 sky-watcher. Meade 就主要係lx-200 之類. Celestron 就由4" 到14" 都放出黎. 亦有section for used equipment. 職員忙緊賣sct focal reducer 俾人, 所以我都冇同佢講野或者係入面影相...
quantumkit
週六 24 4月, 2010 02:06
版面: 天文話題 Everything about Astronomy
主題: 「嫦娥」尋獲萬年能源希望 科大學者﹕月球藏百萬噸核原料 可用作發電
回覆: 2
觀看: 1921

It is very very very well known that the Moon has a lot of Helium-3. This is a scientific result but not really a HUGE scientific discovery. I think the title is a little bit misleading...
quantumkit
週三 21 4月, 2010 10:39
版面: 談天說地 Chatting Square
主題: 麻省理工學院(MIT)──流體力學教程
回覆: 14
觀看: 4253

Mr. 梅西爾, Everyone (including myself) is so interested whether you one day can be an astronomer / astrophysicist / astronaut or scientist of some sort. Being someone already started the journey to one of these, I would sincerely recommend you to read more English books, use more English than Chinese....
quantumkit
週二 06 4月, 2010 09:15
版面: 談天說地 Chatting Square
主題: 級數求Pi?
回覆: 1
觀看: 1348

just a little question, do you study math and science in Chinese or English?
quantumkit
週五 26 3月, 2010 15:28
版面: 天文活動消息 Astro Activity News
主題: 讓更多人知道天文公園吧!
回覆: 70
觀看: 31651

老實講,香港根本冇完美o既觀星地點。

我自己去開東壩,視場闊,方便認星座,睇銀河,仲可以睇埋日出。以前大學時代,三四十人入去,要攞幾多枝鏡都唔係問題(雖然冇試過攞枝6寸Astrophysics)。。

要普及天文,器材根本唔係重點。對外行人來講,最緊要係可以俾佢有地方享受星空。就算各躺係地下,望著個天,乜都唔做都會係一種享受。有時淨係落車個下,見到成條銀河就已經會覺得值回票價。
quantumkit
週四 25 3月, 2010 06:11
版面: 天文物理 Astrophysics
主題: 宇宙膨脹與引力勢能問題
回覆: 77
觀看: 45507

可能 "energy-momentum tensor" 呢個term 誤導左你 等你以為只係將以前既 energy 同 momentum 放在一起而已 實際上,energy-momentum tensor 係一種新既 concept o係四維時空入面,energy-momentum tensor 係講緊十六個量 只不過o係某 d special case 入面我地的確可以分辨到某 d 量同我地以往o既 energy 同 momentum 類似,故得其名 你問我咩係 energy-momentum tensor ,就正如問我咩係 wave-particle (或者 particle-wave)...
quantumkit
週四 25 3月, 2010 05:48
版面: 天文物理 Astrophysics
主題: 宇宙膨脹與引力勢能問題
回覆: 77
觀看: 45507

... technically you can't say about Kinetic energy in terms of GR as well...becoz' the clock and ruler are changing.... If this is true, why I can find formula of KE for SR? :roll: :roll: :roll: SR =/= GR ar ma =.=""" indeed, SR is just a special case in GR... That's exactly what I'm thinking. Why ...
quantumkit
週三 24 3月, 2010 17:00
版面: 天文物理 Astrophysics
主題: 宇宙膨脹與引力勢能問題
回覆: 77
觀看: 45507

[舉黃牌] The gravitational waves carries only a very very very very tiny part of the energy. So-called non-propulsion space-ship is just like throwing a ball up to the sky. A ball with not enough speed will fall down. The initial upward speed is the SAME as the speed when it hits the ground. That is, t...
quantumkit
週五 12 3月, 2010 09:52
版面: 天文話題 Everything about Astronomy
主題: 2012年12月21日世界末日 !!
回覆: 15
觀看: 10718

It is quite disappointing to have such kind of passage on this forum.
quantumkit
週五 05 3月, 2010 16:06
版面: 談天說地 Chatting Square
主題: 恭囍 WenXP !
回覆: 24
觀看: 6421

Congratulation!!!! :P
quantumkit
週二 09 2月, 2010 13:12
版面: 談天說地 Chatting Square
主題: 係facebook見到似曾相識的名稱
回覆: 1
觀看: 1189

anybody has met him in person?
quantumkit
週五 05 2月, 2010 16:28
版面: 天文話題 Everything about Astronomy
主題: 網上定購天文用品
回覆: 24
觀看: 5558

Yes, that will be great for us!!! As mr. yuen pointed out, there are ~8% sale tax for me to buy at OPT. It will be only justified by the products are so unique that people would like to pay the premium and get it fast (v.s. 團購). But stuff on ebay/amazon or companies in the states (other than califo...
quantumkit
週五 05 2月, 2010 14:42
版面: 天文話題 Everything about Astronomy
主題: 網上定購天文用品
回覆: 24
觀看: 5558

I also have a relative in San Diego who helped me a couple of times for shipping OPT products to me in Hong Kong. Those are Meade and Celestron products that OPT can not ship me directly, then I need to take this alternative route. That said, if you live in Califioria, you need to add a 7% local ta...
quantumkit
週五 05 2月, 2010 13:54
版面: 天文話題 Everything about Astronomy
主題: 網上定購天文用品
回覆: 24
觀看: 5558

Probably they have chosen Priority Mail or Express Mail (see usps.com) which include some kind of insurance up to a few hundred USD. The cheapest First Class Mail (平郵) may take longer and do not have tracking number (harder to find in case of missing package). So there are pros and cons between diff...

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