The making of 26 inch Cassegrain - 12, telescope design

[Chanlunlun]

Dear ATMers,

Upon the finishing of optical parts the project enters mechanical construction phase. Here is the specs :-

Aperture :- 26 inches
Type :- Classical Cassegrain at f/10 with Nysmith focus.
Overall length of OTA :- approximately 11 feet.
Zenith eyepiece height :- approximately 60 inches.
Material :- all wood construction.
Mount :- Alt-azm type mount with full GOTO and tracking.
Altitude encoder :- 10000 steps per 360 degree
Azimuth encoder :- 10000 steps per 360 degree
Driving motors and controllers :- ServoCAT.
Navigator :- Argo Navis.
Secondary mirror diameter :- 9.5 inches.
Primary mirror supporting cell :- 27 points floatation.
Primary mirror coating :- single layer silver.
Secondary mirror coating :- single layer aluminium + silicon monoxide.
Overall weight :- about 150 kg.

Hopefully we could finish the whole project before April 2015 before our open day.

Best regards
Chan Yuk Lun
15 Oct 2014

[wtyu21]

預祝大功告成～開到PTC開壇作法，造福大眾～

[Carl Chan]

打造得好！[Good Job]
看來只是有良知，但沒有能力而只會誇誇其談，是做不出如此有實質性的東西。

[Eddy So]

預祝成功！

[benben88]

[bbsdma]

Dear ATMers,

Upon the finishing of optical parts the project enters mechanical construction phase. Here is the specs :-

Aperture :- 26 inches
Type :- Classical Cassegrain at f/10 with Nysmith focus.
Overall length of OTA :- approximately 11 feet.
Zenith eyepiece height :- approximately 60 inches.
Material :- all wood construction.
Mount :- Alt-azm type mount with full GOTO and tracking.
Altitude encoder :- 10000 steps per 360 degree
Azimuth encoder :- 10000 steps per 360 degree
Driving motors and controllers :- ServoCAT.
Navigator :- Argo Navis.
Secondary mirror diameter :- 9.5 inches.
Primary mirror supporting cell :- 27 points floatation.
Primary mirror coating :- single layer silver.
Secondary mirror coating :- single layer aluminium + silicon monoxide.
Overall weight :- about 150 kg.

Hopefully we could finish the whole project before April 2015 before our open day.

Best regards
Chan Yuk Lun
15 Oct 2014

Chan Sir,
That's a good design and the zenith eyepiece position is quite comfortable.

Can I please ask a question? Why upper and lower truss poles connect to the tertiary cage are 45 degrees apart rather than aligning to each other to maximize the rigidity?

Thanks,

[bbsdma]

打造得好！[Good Job]
看來只是有良知，但沒有能力而只會誇誇其談，是做不出如此有實質性的東西。

Chan Sir,
我相信這個論壇上大多數用戶， 或看星， 或拍， 或造， 方向不同,都是實行者

[Chanlunlun]

Dear ATMers,

Upon the finishing of optical parts the project enters mechanical construction phase. Here is the specs :-

Aperture :- 26 inches
Type :- Classical Cassegrain at f/10 with Nysmith focus.
Overall length of OTA :- approximately 11 feet.
Zenith eyepiece height :- approximately 60 inches.
Material :- all wood construction.
Mount :- Alt-azm type mount with full GOTO and tracking.
Altitude encoder :- 10000 steps per 360 degree
Azimuth encoder :- 10000 steps per 360 degree
Driving motors and controllers :- ServoCAT.
Navigator :- Argo Navis.
Secondary mirror diameter :- 9.5 inches.
Primary mirror supporting cell :- 27 points floatation.
Primary mirror coating :- single layer silver.
Secondary mirror coating :- single layer aluminium + silicon monoxide.
Overall weight :- about 150 kg.

Hopefully we could finish the whole project before April 2015 before our open day.

Best regards
Chan Yuk Lun
15 Oct 2014

Chan Sir,
That's a good design and the zenith eyepiece position is quite comfortable.

Can I please ask a question? Why upper and lower truss poles connect to the tertiary cage are 45 degrees apart rather than aligning to each other to maximize the rigidity?

Thanks,

Don't quite understand your question. Please forgive my ignorance.

Tertiary cage? Do you mean the cage holding the diagonal mirror ?

[bbsdma]

Dear ATMers,

Upon the finishing of optical parts the project enters mechanical construction phase. Here is the specs :-

Aperture :- 26 inches
Type :- Classical Cassegrain at f/10 with Nysmith focus.
Overall length of OTA :- approximately 11 feet.
Zenith eyepiece height :- approximately 60 inches.
Material :- all wood construction.
Mount :- Alt-azm type mount with full GOTO and tracking.
Altitude encoder :- 10000 steps per 360 degree
Azimuth encoder :- 10000 steps per 360 degree
Driving motors and controllers :- ServoCAT.
Navigator :- Argo Navis.
Secondary mirror diameter :- 9.5 inches.
Primary mirror supporting cell :- 27 points floatation.
Primary mirror coating :- single layer silver.
Secondary mirror coating :- single layer aluminium + silicon monoxide.
Overall weight :- about 150 kg.

Hopefully we could finish the whole project before April 2015 before our open day.

Best regards
Chan Yuk Lun
15 Oct 2014

Chan Sir,
That's a good design and the zenith eyepiece position is quite comfortable.

Can I please ask a question? Why upper and lower truss poles connect to the tertiary cage are 45 degrees apart rather than aligning to each other to maximize the rigidity?

Thanks,

Don't quite understand your question. Please forgive my ignorance.

Tertiary cage? Do you mean the cage holding the diagonal mirror ?

Chan Sir,
Sorry for the elusive Chinglish I was using, and yes referring tertiary cage I did mean 装载第三镜的笼子 if I may say it in simplified Chinese.

[bingsze]

其實你直接用中文寫過來就可以，他只是沒有甚麼中文輸入法而已！

[bbsdma]

其實你直接用中文寫過來就可以，他只是沒有甚麼中文輸入法而已！

Bing sir见谅，
公司电脑也没有中文ime，上班打汉字只能用手机慢慢来甚不便也不会用繁体，还怕老板看到

相比手机我还是打二脚猫英文比较快捷

[Chanlunlun]

預祝大功告成～開到PTC開壇作法，造福大眾～

The telescope is huge. The probabilty is very slim.

[Chanlunlun]

Dear ATMers,

Upon the finishing of optical parts the project enters mechanical construction phase. Here is the specs :-

Aperture :- 26 inches
Type :- Classical Cassegrain at f/10 with Nysmith focus.
Overall length of OTA :- approximately 11 feet.
Zenith eyepiece height :- approximately 60 inches.
Material :- all wood construction.
Mount :- Alt-azm type mount with full GOTO and tracking.
Altitude encoder :- 10000 steps per 360 degree
Azimuth encoder :- 10000 steps per 360 degree
Driving motors and controllers :- ServoCAT.
Navigator :- Argo Navis.
Secondary mirror diameter :- 9.5 inches.
Primary mirror supporting cell :- 27 points floatation.
Primary mirror coating :- single layer silver.
Secondary mirror coating :- single layer aluminium + silicon monoxide.
Overall weight :- about 150 kg.

Hopefully we could finish the whole project before April 2015 before our open day.

Best regards
Chan Yuk Lun
15 Oct 2014

Chan Sir,
That's a good design and the zenith eyepiece position is quite comfortable.

Can I please ask a question? Why upper and lower truss poles connect to the tertiary cage are 45 degrees apart rather than aligning to each other to maximize the rigidity?

Thanks,

Don't quite understand your question. Please forgive my ignorance.

Tertiary cage? Do you mean the cage holding the diagonal mirror ?

Chan Sir,
Sorry for the elusive Chinglish I was using, and yes referring tertiary cage I did mean 装载第三镜的笼子 if I may say it in simplified Chinese.

Sorry for delaying so long. I forgot to reply.

The diagonal cage is connected to primary mirror box by struss. Struss can provide very stable structure with very light weight. That's the concern.