www.astrocafe.hk

Just back from a holiday at Iguazu Falls, Argentina. It was recently elected as one of the new 7 wonders of the world. But an equally big wonder for me was a chance to see a comet with a tail extending 30-40 degrees across the sky. Being able to observe it from the balcony of my hotel room, I was able to see it every night. My jet lag certainly helped in getting me up early in the morning.

With no intention to do any stargazing in the trip initially, I didn't bring any equipment to observe it. So I only used a pair of 8x42 binoculars (rather than my beloved Canon 15x50) to observe, and using some chairs and tables to make up a shooting platform for photography. The following pic was taken on 27 Dec which has the tail longer than the subsequent days.

Equipment: Canon 17-40mm lens + 60D camera
Exposure: 30s, f4, ISO 6400 with dark frame subtraction

Really lovely! I guess if u have serious instrument, the photo must be stunning!

willis 寫:Really lovely! I guess if u have serious instrument, the photo must be stunning!

不會啦，拍這些大彗星，要麼廣角鏡，要麼拍彗頭大特寫，前者來說還是考慮構圖，跟器材關係不太。

過去三十年來，在香港能看到三四十度長彗尾，應是96年的百武彗星，我有幸在雲隙看到數分鐘。

我也在想，是否要在西藏置套廣角拍攝系統。

社長 寫:

willis 寫:Really lovely! I guess if u have serious instrument, the photo must be stunning!

不會啦，拍這些大彗星，要麼廣角鏡，要麼拍彗頭大特寫，前者來說還是考慮構圖，跟器材關係不太。

過去三十年來，在香港能看到三四十度長彗尾，應是96年的百武彗星，我有幸在雲隙看到數分鐘。

我也在想，是否要在西藏置套廣角拍攝系統。

Any improvement if light pollution filter is used?

若在有光害的環境下當然有幫助，但在無光害環境下，若要加強彗星及天空背景的對比度，是有一些特定的彗星濾鏡的，這個我沒深究　

Comet filters: http://www.lumiconfilters.com/filter-li ... et+Filters

Lumicon廿年前已出品這些濾鏡了，但當時還是學生負擔不起。

反而我今晚學習觀測掩星，20等的Varuna(KBO Kuiper belt object)掩16等的恆星，但郤遇上11月以來首場雪，很大機會失望了。

viewtopic.php?f=20&t=1389&p=13794#p13794

God bless u!

oh my god.... 天氣轉晴了

那個「西藏的雨夜」似乎是祝福多於大話！

Comet Lovejoy on 28 Dec

Comet Lovejoy on 29 Dec. It was my last day of observation as the comet was getting less and less impressive. You can see that the tail was significantly shorter than that on 27 Dec. The motion of the comet was also quite significant. It was now appearing to be plunging into the waterfalls.

用雙筒鏡看，彗核是否結實? 彗髮型態如何? 彗尾有沒有顏色?

社長 寫:用雙筒鏡看，彗核是否結實? 彗髮型態如何? 彗尾有沒有顏色?

The nucleus was very low in the sky. I could not find a clear nucleus and I certainly didn't see any colour. The best view was the naked eye view - a long tail.

David 寫:The best view was the naked eye view - a long tail.

同意的，97年在興隆用肉眼看Hale-Bopp就是這樣子，和照片無大分別，每晚可以凝望它兩小時以上，天亮前又升出來，但得承認，在天空中出現一顆大彗星，會有一種不大自然的感覺，我開始明白古人對彗星的觀感也是這樣來的。

跑題一下，你是如何飛到阿根庭的? 經美國西岸南下?

社長 寫:跑題一下，你是如何飛到阿根庭的? 經美國西岸南下?

It took 4 flights to get there:
1. From Hong Kong to New York (About 16 hours)
2. From New York to Santiago, Chile (Stoppint at Lima, Peru) (About 14 hours)
3. From Santiago to Buenos Aires International Airport (About 3 hours)
4. From Buenos Aires Domestic Airport to Iguazu Falls Airport (about 1.5 hours)

It could be slightly easier if I stopped at Auckland or Europe rather than New York, but I booked the flights quite late and it was a very busy week as you could imagine.

10年前認識了一位在阿根庭教日文的女教授，和我同齡的，來香港時探我時住在我家10天，經美國Florida及西岸，然後日本來港要30小時。

後來又透過她介紹，到東京時認識了一位來自阿根庭的西班牙語教授。

willis 寫:那個「西藏的雨夜」似乎是祝福多於大話！

我看不出那是謊言，因為先要懂才可說是為非。

當他說在香港，行星是不會出現在天頂，已反映了他的天文地理水平真的不足，要去理解千里之外的西藏的天氣系統，是有點夏蟲雨冰了，所以才會說什麼 "...西藏阿里是高不是原、是山不是原不屬青藏高原...."

正如前天文台長林超英說，好些理科碩士來應聘科學主任，連在世界地圖上找出香港也不成，那行為藝術博士有這表現，實在不足為奇。