20 inch telescope in Australia - 1, full metal jacket

[Chanlunlun]

Dear ATMs,

Together with Chan OC and Chung HL we will proceed to Western Australia tonight for a star trip ( and site seeing, of course ). As usual the 20 inch telescope will travel along with us for observing the beautiful gems in the southern sky.

Australia has a very strict code of importing wood into their country. In order to get through the custom more easily the whole telescope, including the OTA and the alt-az mount, has to be reconstructed using full metal. It takes me a continuous working of two weeks, spending a few hundred dollars, to convert the telescope from a full wooden to a metal one.

However there is still some components that cannot be made from metal, the altitude bearing is one and the mirror cell base plate is the other. ( metallic ones will be too heavy and too expansive ) If they don’t get the custom we have to switch to plan B – to buy wood inside Australia and make the components by ourselves immediately.

Although metal has a much higher density than wood but the metallic telescope weighs a little less than the wooden one, due to the extensive use of aluminium angle bars for construction..

Best regards
Chan Yuk Lun
15-8-2006

[Wah!!]

陳倫倫竟然用金屬支架
仲以為我眼花添

[simonii]

why is that the trusses in metal version are triangular shape pointing to the bottom?
the moment to the horizontal bars at the primary mirror cage will be large

[Wah!!]

副鏡箱和主鏡座箱的結構都是長方形, 沒有三角形.
是否需要補強呢?

[Chanlunlun]

why is that the trusses in metal version are triangular shape pointing to the bottom?
the moment to the horizontal bars at the primary mirror cage will be large

Dear Mr. Simonii,

Since the secondary cage is rectangular in shape the struss must be installed in the iinverted triangle shape for stability. Even professional telescopes ( e.g. WYIN ) are constructed in this way.

Best regards
Chan Yuk Lun

[Chanlunlun]

副鏡箱和主鏡座箱的結構都是長方形, 沒有三角形.
是否需要補強呢?

Dear Mr. Wah,

The struss are in triangular arangement provides all the strength. The whole telescope is very rigid, we tested it.

Best regards
Chan Yuk Lun

[Chanlunlun]

陳倫倫竟然用金屬支架
仲以為我眼花添

Dear Mr. Wah,

If I could have an option I will never construct telescope using metal. It is expensive and difficult to handle with. But Asutralia does not allow wooden telescope to get into their country and so that's it.

Best regards
Chan Yuk Lun

[Hay]

除了望远镜改成金属支架外，3/5A+AB1 亦换成Martinlogan了。

不知陈Sir 有没有将Power Amp 也换了呢？

Hay

[david_kmng]

Just curious if the telescope loses weight?

[Wah!!]

副鏡箱和主鏡座箱的結構都是長方形, 沒有三角形.
是否需要補強呢?

Dear Mr. Wah,

The struss are in triangular arangement provides all the strength. The whole telescope is very rigid, we tested it.

Best regards
Chan Yuk Lun

我的疑感不在於三角形結構的筒身, 而是副鏡箱和主鏡箱.
筒身的三角形是不會使長方形結構的副鏡箱和主鏡箱變得更牢固的.
相信它們穩固是因為角鋁和螺絲的金屬強度, 而不在於結構/設計上的穩固.

[Steve]

The wooden altitude bearing is painted with gloss oil?

[Chanlunlun]

The wooden altitude bearing is painted with gloss oil?

They were painted with liquor. It would be easier to broing wood into Australia if they are painted by liquor in advance.

But Newzeland has even stricter code of importing wood. I think the wooden bearing will be replaced by PVC ones before the telescope arrive there this Christmas.

[Steve]

The wooden altitude bearing is painted with gloss oil?

They were painted with liquor. It would be easier to broing wood into Australia if they are painted by liquor in advance.

But Newzeland has even stricter code of importing wood. I think the wooden bearing will be replaced by PVC ones before the telescope arrive there this Christmas.

I have a CNC router/milling machine for boards. Let me know if you need machining...

[Chanlunlun]

The wooden altitude bearing is painted with gloss oil?

They were painted with liquor. It would be easier to broing wood into Australia if they are painted by liquor in advance.

But Newzeland has even stricter code of importing wood. I think the wooden bearing will be replaced by PVC ones before the telescope arrive there this Christmas.

I have a CNC router/milling machine for boards. Let me know if you need machining...

CNC machine ? On my god !!!

Let us keep in touch.