Ha太陽 (1-11-2013)

[David]

活躍區AR1884和1885

[社長]

LS152T?

David 總是要不時告訴我們，他是香港最佳太陽攝影師，難以想像LS230T在你手上會如何

[David]

對，是LS152T + 1.75x Barlow，100%出圖。視寧度不佳，拍攝超過6千張圖，只疊合1000左右。

今季我刻意把小鏡APM 80/480折射鏡留在家中，逼自己一定要用大鏡拍攝，才出到這幾天的高倍照片。其實這張圖片沒有需要運用什麼特別技巧，反而拼圖和動畫則要多一點耐性。

viewtopic.php?f=15&t=3755#p23943
viewtopic.php?f=15&t=3753#p23913

[社長]

拍6000張的時間很長，會不會活躍區本身的變化，讓疊加後的影像已柔化了?

[David]

拍6000張的時間很長，會不會活躍區本身的變化，讓疊加後的影像已柔化了?

有可能，但拍了3段片，原本想做動畫，但其實變化很小，所以放棄了

[David]

模仿Alan Friedman處理手法的日珥
http://avertedimagination.com/

[Raymond TSE]

Dear David,

Impressive high resolution L152 imaging at 0.65A bandwidth.

I also want to start solar Ha imaging (still and timelapse) this month.

Since the prominences/filaments may change quite slowly, would it be necessary to capture short video clips over extended period
say 4-6 hours during morning/afternoon ? in order to see some moderate changes of the prominence/filament movements ?

Raymond Tse

[David]

Since the prominences/filaments may change quite slowly, would it be necessary to capture short video clips over extended period
say 4-6 hours during morning/afternoon ? in order to see some moderate changes of the prominence/filament movements ?
Raymond Tse

For high magnification shots of prominence (around 1500mm or above), my experience showed that significant changes can be seen in just 10 min - 20 min. The time between videos is about 1-2 minutes.

For low magnification shots (which I haven't tried), of course you need longer time to see obvious changes. But I would expect a time frame of much much shorter than 4-6 hours unless you want to record really long period of changes.

For active regions/sunspot groups/filaments on the solar disk, I had not done any serious animation yet. So I don't know what is the usual time frame.

As changes can happen quite quickly, it is more ideal to keep each video short. However, other factors may come into play which makes this not feasible. e.g. If the seeing is very poor (which is often what I get during lunch time), a short video can result in only very few good images. The stacked image will therefore be noisy. In such case, I personally prefer a less noisy final image by recording longer period and stacking more frames. - It is always a matter of compromise.

[kelvincheboy]

一流的黑子

[社長]

以David的拍攝條件得出這樣的效果，堪稱港島東區最佳的石屎森林午飯小休不對極軸走廊流動式高倍日面攝影師：

viewtopic.php?f=15&t=3747#p23879

從他儲存器材的房間，移出這個上佳的拍攝地點，距離約15372毫米。

所以Kelvin你的條件一定比他好

[David]

堪稱港島東區最佳的石屎森林午飯小休不對極軸走廊流動式高倍日面攝影師：

你指我是北緯22度16'58.14"、東經114度13'26.93" 的最佳日面攝影師

我會積極考慮用流動pier，令學生和我可以更輕鬆地拍攝

[社長]

不，你的範圍大些，鄰近兩三萬人口中，你也是最好的，已比我到過的一些國家人口多了：

viewtopic.php?f=13&t=91&p=22385&hilit=

我也是很孤獨的，香港好像沒什麼愛好者喜歡拍彗星，只有我不停在拍：

viewtopic.php?f=16&t=3759