Making of 16 inch PTC telescope - 9, Telescope Finished

[Tarepanda]

真係神速
想問下,
你會帶支M 16寸出去還是這支呢?

Dear Mr. Panda,

M16 ? What is it ? Is it a gun or sometinhg ?

Best regards
Chan Yuk Lun

SORRY呀,係 MEADE那支16寸的杜蘇鏡呀
它一定比你那支要重很多,但不知道它的波長是否也能達到你那支1/8的精度呢?

[Chanlunlun]

真係神速
想問下,
你會帶支M 16寸出去還是這支呢?

Dear Mr. Panda,

M16 ? What is it ? Is it a gun or sometinhg ?

Best regards
Chan Yuk Lun

SORRY呀,係 MEADE那支16寸的杜蘇鏡呀
它一定比你那支要重很多,但不知道它的波長是否也能達到你那支1/8的精度呢?

Dear Mr. panda,

Oh I see !

The Meade 16 inch LightBridge has its own problems :-

1. At 130 lbs it is just too heavy to be carried out by any means.

2. Geometrically speaking it is just to big to fit into a car.

So I belief that it will not appear anywhere outside the house in Water Mouth. However it has good optics. I haven't tested it yet but the optic is certainly good.

Best regards
Chan Yuk Lun

[Tarepanda]

那希望WFC2那支12寸鏡能早日在水口開光啦
據聞當天要3個人+一輛車才能把12寸的杜蘇運進PTC

[Chanlunlun]

那希望WFC2那支12寸鏡能早日在水口開光啦
據聞當天要3個人+一輛車才能把12寸的杜蘇運進PTC

Dear Mr. panda,

What ?

The 12 inch LightBridge was bought long time ago. It should have been first lighted in Water Mouth. At least it was first lighted in PTC few months ago.

Best regards
Chan Yuk Lun

[Tarepanda]

是呀,第一次開光是在PTC
但唔知WFC2有沒將佢運去水口基地作為長久觀測之用
那麼大的鏡子,只有在水口才能很好的發揮它的口徑功用

[Skyobs]

那麼大的鏡子,只有在水口才能很好的發揮它的口徑功用

為何在天較黑的地方才能發揮大口徑的功用? 不是在天較光的地方,大口徑讓你上高倍又得,用UHC濾鏡又得嗎?

[Chanlunlun]

那麼大的鏡子,只有在水口才能很好的發揮它的口徑功用

為何在天較黑的地方才能發揮大口徑的功用? 不是在天較光的地方,大口徑讓你上高倍又得,用UHC濾鏡又得嗎?

Dear Mr. SkyObs,

Theorectically speaking a bigger telescope can view fainter object even in light polluted sky. But everthing has a limit - HK urban sky is just way too polluted.

Practical experiences tell that under such light fogged sky even big telescope is useless. Hence the only place to fully release the power of big telescope is outside urban. Once outside heavily polluted sky, even in sub-urban skies such as PTC, big telescope is advantageous.

Best regards
Chan Yuk Lun

[bbsdma]

請教兩個問題：
1. 從16.jpg看，斜鏡座只有一顆大螺絲， 不見其他三顆調節螺絲。Chan sir 是如何微調斜鏡角度的？
2. Chan Sir 的作品次鏡籠都很長（調焦座靠主鏡端離次鏡籠的環有一大段距離），這對減輕次鏡籠的重量，提高其剛性都有不利影響。 請問是出于用一個足夠長的次鏡籠做擋光的目的嗎？

謝謝

[bingsze]

咁快又一年了，

鏡神，你的三十吋進展如何？

千祈唔好浪費了它！

最多幫你托上大陸啦！

[Chanlunlun]

請教兩個問題：
1. 從16.jpg看，斜鏡座只有一顆大螺絲， 不見其他三顆調節螺絲。Chan sir 是如何微調斜鏡角度的？
2. Chan Sir 的作品次鏡籠都很長（調焦座靠主鏡端離次鏡籠的環有一大段距離），這對減輕次鏡籠的重量，提高其剛性都有不利影響。 請問是出于用一個足夠長的次鏡籠做擋光的目的嗎？

謝謝

Dear Mr. bbsdma,

1. The spider has eight legs. By adjusting the end nuts of the spider legs the angle of diagonal mirror can be adjusted. This design can provide very big strength and stability in holding a heavy diagional mirror.

2. I am happy you notice that. the extra length is used to shield off stray light and to avoid dew formation on the secondary. As field experioence tells, this extra length does not affect the stability at all.

Best regards
Chan Yuk Lun

[bbsdma]

Dear Mr. bbsdma,

1. The spider has eight legs. By adjusting the end nuts of the spider legs the angle of diagonal mirror can be adjusted. This design can provide very big strength and stability in holding a heavy diagional mirror.

2. I am happy you notice that. the extra length is used to shield off stray light and to avoid dew formation on the secondary. As field experioence tells, this extra length does not affect the stability at all.

Best regards
Chan Yuk Lun

謝Chan Sir 解惑！