轉貼 - 國產 61cm 牛頓鏡

[Wah!!]

http://www.astronomy.com.cn/bbs/thread-116150-7-2.html

61cm 口徑集光力強, 可惜焦距長得嚇人, 3.5米!!!

[funoooo]

[Wah!!]

鋁梯的高度只有鏡身一半, 危險......

[MANDII]

甘大支镜买就的确不可能。
做是唯一办法。
我觉得呢D支架同下身都不是太难做，订做也好容易。
但系最难的,最高难度的,便是甘大的主镜片和副镜片

[Chanlunlun]

Dear ATMers,

This telescope is just too long to be safely operated.

It looks like that the mirror is a f/6. For a 24 inch class telescope the ideal f/no. should be faster than f/4. Our 24 inch has a f/no. 3.4, still it is judged to be a little bit too long when used in field.

Nevertheless it is good to see the emergence of huge telesocpe among the ATMing circle in mainland.

Best regards
Chan Yuk Lun

[MANDII]

想想下.. .
其实我都有D兴趣想搞枝特大的镜,张来
因为买是不可能的了

[大黃傻貓GARFIELD]

Dear ATMers,

This telescope is just too long to be safely operated.

It looks like that the mirror is a f/6. For a 24 inch class telescope the ideal f/no. should be faster than f/4. Our 24 inch has a f/no. 3.4, still it is judged to be a little bit too long when used in field.

Nevertheless it is good to see the emergence of huge telesocpe among the ATMing circle in mainland.

Best regards
Chan Yuk Lun

f/6 真的是太長了﹐ 如果是 f/4以下﹐ 使用時候會方便好多。鏡神那台24"就剛剛適合。

[鄧登凳]

Dear ATMers,

This telescope is just too long to be safely operated.

It looks like that the mirror is a f/6. For a 24 inch class telescope the ideal f/no. should be faster than f/4. Our 24 inch has a f/no. 3.4, still it is judged to be a little bit too long when used in field.

Nevertheless it is good to see the emergence of huge telesocpe among the ATMing circle in mainland.

Best regards
Chan Yuk Lun

f/6 真的是太長了﹐ 如果是 f/4以下﹐ 使用時候會方便好多。鏡神那台24"就剛剛適合。

24吋 f/4, 焦距8呎, 支鏡約長7呎, 都要"擔梯"

[Chanlunlun]

Dear ATMers,

This telescope is just too long to be safely operated.

It looks like that the mirror is a f/6. For a 24 inch class telescope the ideal f/no. should be faster than f/4. Our 24 inch has a f/no. 3.4, still it is judged to be a little bit too long when used in field.

Nevertheless it is good to see the emergence of huge telesocpe among the ATMing circle in mainland.

Best regards
Chan Yuk Lun

f/6 真的是太長了﹐ 如果是 f/4以下﹐ 使用時候會方便好多。鏡神那台24"就剛剛適合。

24吋 f/4, 焦距8呎, 支鏡約長7呎, 都要"擔梯"

Dear Mr. Tang,

Yes and No.Yes, we need a "ladder" but "no", the ladder is in most cases used as a chair.

See the attached picture and you will feel the actual ratio of our 24 inch f/3.4 telescope. The primary mirror of our 24 inch is vert fast.

So, fast means what ? Obviously fast means short, fast means light weight, fast means portability and, ultimately, fast means a USUABLE BIG telesocpe.

4 years ago when we designed this telescope we already knew what is the true meaning of "FAST" .

Best regards
Chan Yuk Lun

[c++]

甘大支镜买就的确不可能。
做是唯一办法。
我觉得呢D支架同下身都不是太难做，订做也好容易。
但系最难的,最高难度的,便是甘大的主镜片和副镜片

據鏡主自述， 大概造價已接近6位數（RMB)， 如果不是為了享受做的過程，直接買一流質量 的obsession 22" UC版（10K USD ）或者 25“ F/4（13.5K USD）都要平價、輕身、高性能和最重要的，目鏡高度低（245cm vs 360cm）。

[Chanlunlun]

甘大支镜买就的确不可能。
做是唯一办法。
我觉得呢D支架同下身都不是太难做，订做也好容易。
但系最难的,最高难度的,便是甘大的主镜片和副镜片

據鏡主自述， 大概造價已接近6位數（RMB)， 如果不是為了享受做的過程，直接買一流質量 的obsession 22" UC版（10K USD ）或者 25“ F/4（13.5K USD）都要平價、輕身、高性能和最重要的，目鏡高度低（245cm vs 360cm）。

Dear Mr/Miss C++,

Spending huge money in DIYing seems a nightmare to me. Of course everybody is free to has his own style.

For me, I tend to spend least in obtaining most. I got similiar experience in building a 24 inch telescope, just spending around HKD 3000.

Most of the money was spend on buying #40 grits and two pieces of glass. Others costed nearly nothing ( the secondary mirror was shared among the 16 inch, 20 inch, 24 inch and 30 inch telescopes ). In particular we took surplus plywoods from construction site. We just recycled the garbage and turend them into a telescope.

Frankly speaking I am a big fans of Dobson, who built big telescopes out of cheap stuffs.

Best regards
Chan yuk Lun

[苏鲁锭]

...........據鏡主自述， 大概造價已接近6位數（RMB）...........

玩天文望远镜是个很费钱的事。
这么大的镜子想便宜，就好不了。
口径200以下的镜子无论玻璃如何，环境如何，很容易做到1/20波长的精度。
口径600的镜子，要做到1/10波长的精度，对玻璃，磨制，支撑，环境，检测.........就有很严格的要求了。
.........
要想做好口径600的天文望远镜，花个6位数，不算很多。

[Wah!!]

若東西都是 DIY 的話, 價格可以少一個零.
若東西是給別人做的話, 比廠鏡價也不稀奇.

[苏鲁锭]

若東西都是 DIY 的話, 價格可以少一個零.
若東西是給別人做的話, 比廠鏡價也不稀奇.

厂家没有10倍的利润。

[philip425]

是沒有10倍的利润, 問題是產品從原型到成品再到消費者手中, 中間增加了不少費用, 所以售價比單一成本價(只計原料成本)高出十倍不足為奇. 當然還要看物料成本占總體成本多少.