My Deepsky photos on 2004/10/18 at Pak Tam Chung (Final vers

[elton]

Image taken on 2004/10/18 night at Pak Tam Chung
Telescope : Celestron c80wa refractor
Mount : Modified Zhitong EQ4
Guiding : C5 guidescope + DIY Autoguider with software Startrack
Camera / Film : Nikon FM2 / Fuji Press 800
Exposure : 20 mins + 5 mins

M42 Please comment.

[elton]

Images taken on 2004/10/18 night at Pak Tam Chung
Telescope : Celestron c80wa refractor
Mount : Modified Zhitong EQ4
Guiding : C5 guidescope + DIY Autoguider with software Startrack
Camera / Film : Nikon FM2 / Fuji Press 800
Exposure : 3 x 15 ~ 20 mins

M45 Please comment.

[elton]

Very subtle Horsehead and Flame nebula taken on 2004/10/18 at Pak Tam Chung
Almost couldn't see lar.

Image taken on 2004/10/18 night at Pak Tam Chung
Telescope : Celestron c80wa refractor
Mount : Modified Zhitong EQ4
Guiding : C5 guidescope + DIY Autoguider with software Startrack
Camera / Film : Nikon FM2 / Fuji Press 800
Exposure : 40 mins

[jj1516]

8錯8錯!

[豆豸苗]

噢. m45 有雲氣啊~
用 c80wa 啊~~~ 我又好想試下添~~~ ^^

Modified Zhitong EQ4 --- 點 modified 法? ^^?

[Wah!]

是否指改裝到適用於香港緯度?

[elton]

Thanks for the comments.
I think c80wa is really a low cost beginner scope not only for visual but also for astrophotography. I was inspired by a person in Chile who used this scope and produced bunge of great photos! Initially I bought that for guidescope of C5, but I think i will use that more.
For the modification of the Zhitong EQ4 mount, I changed the stop so it can work okay in HK's attitude, and I also reduced the radial play (clearance) of the Alt. axis of the mount so it is more stable, and also making it with autoguide capability.

[豆豸苗]

icic~ Thanks for sharing. ^^

Hope I can have more chance to use my c80wa too. ^^

[dobs]

I was inspired by a person in Chile who used this scope and produced bunge of great photos!

Is him?
http://astrosurf.com/victor

[豆豸苗]

呢張好有趣:
http://astrosurf.com/victor/new/new4.htm

[elton]

dobs! exactly from this person! I only found his photos in the in the yahoo 80mmf5 egroup. Thanks a lot!!! That is a good reference!!!

[Subaru]

Image taken on 2004/10/18 night at Pak Tam Chung
Telescope : Celestron c80wa refractor
Mount : Modified Zhitong EQ4
Guiding : C5 guidescope + DIY Autoguider with software Startrack
Camera / Film : Nikon FM2 / Fuji Press 800
Exposure : 20 mins + 5 mins

M42 Please comment.

Good start. I would like to recommend you to try the C5 with 0.63x prime focus next time. It should give less CA than your refractor.

[elton]

Thanks Subaru!!! I will try my little gem C5 + 0.63 x reducer next time. The reason why i used 80 mm was because it has a smaller f-number, which let me do shorter exposure (higher possibility of success as I am a real beginner. )
By the way, I do not know much about the 0.63 reducer even I got one. I only know that it could reduce the exposure time by half and obtained a virtually wider view (actually I was told it is just smaller in size and the 'wider view' are just vignetting black corners). I want to know increasing or decreasing the distance between the reducer and film will cause what effect? I have seen some accessories from Steve Mogg (who sells Toucam adapters), I previously bought the 0.66x reducer and one 0.3 x extender intended for Toucam long exposure. The 0.66x reducer looks just like our Meade/Celestron 0.63 reducer, but only smaller in size, for the extender, it is just a tube to increase the distance between the Toucam CCD and reducer. Will the f-number of my existing C5 and 0.63 x reducer further decrease if I insert a tube between them???
Please help. Thanks in advance.

[Subaru]

1. I will try my little gem C5 + 0.63 x reducer next time. The reason why i used 80 mm was because it has a smaller f-number, which let me do shorter exposure (higher possibility of success as I am a real beginner. )
2. By the way, I do not know much about the 0.63 reducer even I got one. I only know that it could reduce the exposure time by half and obtained a virtually wider view (actually I was told it is just smaller in size and the 'wider view' are just vignetting black corners).
3. I want to know increasing or decreasing the distance between the reducer and film will cause what effect? I have seen some accessories from Steve Mogg (who sells Toucam adapters), I previously bought the 0.66x reducer and one 0.3 x extender intended for Toucam long exposure. The 0.66x reducer looks just like our Meade/Celestron 0.63 reducer, but only smaller in size, for the extender, it is just a tube to increase the distance between the Toucam CCD and reducer. Will the f-number of my existing C5 and 0.63 x reducer further decrease if I insert a tube between them???
Please help. Thanks in advance.

1. You must try it as you definitely won't be satisfied with a 3" refractor.
2. The main benefit of the 0.63x reducer is the shortening of the exposure time. The fully illuminated field is just about the same as at f/10, so field of view should not be a main reason to go for the reducer. By the way, field curvature becomes more severe with the reducer.
3. Yes, increase the distance between the reducer and focal plane will decrease the effective focal ratio of the setup. However, you can't go too far due to the abberrations it introduces.

[Tarepanda]

多謝豆貓提供有關c8的link,效果確實不錯,咁我對c102a更加有信心啦
不過Wah!成日提到cool,係唔係指冷凍法?適合電腦攝影還是一般攝影的?
需要什麼儀器的?你成日都提到noise這個詞又是什麼東東來的?