ZWO Seestar S50 拍冥王星 

Capturing Pluto with the ZWO Seestar S50

又是趁陰雨天時處理一下日前拍攝的影像, 原來在海洋公園光影匯演時也能輕鬆拍下冥王星。這輩子只拍過2次冥王星，上次是用自己西藏遙控天文台的Officina Stellare RiFast 500口徑卡反拍，這次郤是口徑小10倍，只有5公分的Seestar，還要在香港這種Bortle 9天空拍，感覺既興奮又複雜。

照片一 : 2023年9月25日攝於星河科研社新界西活動基地，當晚冥王星離農曆十二的大月亮外才10度距離。

照片二 : 2023年9月月29日中秋節攝於海洋公園晚上光影匯演期間，當晚透明度很低，肉眼目視星等才2等多點，但同樣是累計曝光5分鐘，最暗但能清晰拍下到15.5等星左右。

以Seestar的相機每像素取樣度2.4角秒，最少要三四小時才能檢測到冥王星在天空的移動，但隔一天比較合理。現在兩張照片隔開4天，移動就很明顯了。我們後面的每月觀星實習可以試拍這個 https://eshop.astro.hk/hk/catalogs/lists?sfor=default&sfna=%E8%A7%80%E6%98%9F%E5%AF%A6%E7%BF%92

Once again, taking advantage of rainy days to process the images taken earlier, I realized that I could easily capture Pluto during the Ocean Park Multimedia Shows. In my lifetime, I have only imaged Pluto twice. The previous time, I used my own remote-controlled astronomical observatory in Tibet with the Officina Stellare RiFast 500 Reflector. This time, the aperture is 10 times smaller, with only a 50mm Seestar. Moreover, I had to capture it in the Bortle 9 sky of Hong Kong, which added an excitement yet mixed feeling.

Photo 1: Taken on September 25, 2023, at the Galaxy Scientific Group activity base in New Territories West. On that night, Pluto was just 10 degrees away from the near full moon.

Photo 2: Taken on September 29, 2023, during the Mid-Autumn Festival at Ocean Park's Multimedia Shows. The transparency was very low that night, with a naked-eye visual magnitude of only around 2th. However, with a accumulated exposure of 5 minutes, I was able to clearly capture stars as faint as magnitude 15.5th. 

With the Seestar camera's pixel sampling of 2.4 arcseconds, it would take at least three to four hours to detect Pluto's movement in the sky, but it is more reasonable to observe the change over a day. The two photos were taken four days apart, and the movement is quite noticeable. We can try capturing this during our monthly stargazing workshop in the future https://eshop.astro.hk/en/catalogs/lists?sfor=default&sfna=stargazing%20workshop