昆明紅土地 - Virgo Cluster of Galaxies

[HK.Raymond.Tse]

各位，

同樣在紅土地拍攝的Virgo Cluster of Galaxies，資料如下：

日期：2006年12月25日(星期一)
時間：零晨5.07 am
月齡：初五(已下山)
地點：云南省東川新田鄉(紅土地)
海拔：2,483m
氣溫：0-1C
濕度：--
透明度：8-9/10
視寧度：6/10
目視星等：5.8等或更佳
天氣：晴空万里、微風、露水、地面結霜

鏡：Orion 80ED 折射鏡
焦比：F7.5
拍攝机身：(改裝)Canon 350D
赤導儀：高橋EM200 Temma 2
導星鏡：Canon 135mm F4
導星儀器：SBIG ST402ME

ISO ： 800
曝光：每張3分鐘
加叠：6張

Raymond Tse

[Koey]

These are great photos ..^^..

[anguslau]

Very nice! Is this full frame or cropped?

Love to see more stars in the star field. Did you deliberately darken the background to standout the glaxies? Given the dark sky conditions, any particular reasons not doing more than 3min subs?

[Wah!!]

好靚!

[HK.Raymond.Tse]

Most of the frame, with 4/5 crop.

Due to short focal length of guidescope at 135mm only, and possible some flexture in the whole imaging setup, guiding was very unsatisfactory, thus limiting my autoguide to 3 min only.

My orginal plan was to guide up to 10 min. (would have to wait for another astro trip to do longer autoguiding).

The total exposure time was still very short and thus noise was obvious when I stretch the image to show the details of galaxies. Thus, I roughly set the black point to darken the background and to stand-out the galaxies.

Now, not a very "deep" image.

[Subaru]

Very good!