OTA of 24 inch telescope completed
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
OTA of 24 inch telescope completed
Dear ATMs,
The optical tube assembly ( OTA) of the 24 inch telescope has been finished today. It is basically a classical Sierrus Struss design with black cloth covering up the secondary cage for blocking off the stray light.
With the diagonal mirror, an UWV 14-mm eyepiece and the finderscope fixed into place, we are able to find the location of the center of gravity of the OTA. The center of gravity lies at 16.5 inches from the bottom of the mirror cell. With this data on hand we can then design the rocker arm and the alt-alz mount for the instrument.
The rocker arm and the alt-alz mount will be finished soonest to take advantage of the reoccurrence of fine weather these days so that we can carry out the star test. It is not until the star test can we calibrate the Offner tester to fine tune the surface of the mirror.
Hopefully we can finish the whole project within two weeks.
Best regards
Chan Yuk Lun
13-4-2004
The optical tube assembly ( OTA) of the 24 inch telescope has been finished today. It is basically a classical Sierrus Struss design with black cloth covering up the secondary cage for blocking off the stray light.
With the diagonal mirror, an UWV 14-mm eyepiece and the finderscope fixed into place, we are able to find the location of the center of gravity of the OTA. The center of gravity lies at 16.5 inches from the bottom of the mirror cell. With this data on hand we can then design the rocker arm and the alt-alz mount for the instrument.
The rocker arm and the alt-alz mount will be finished soonest to take advantage of the reoccurrence of fine weather these days so that we can carry out the star test. It is not until the star test can we calibrate the Offner tester to fine tune the surface of the mirror.
Hopefully we can finish the whole project within two weeks.
Best regards
Chan Yuk Lun
13-4-2004
- 附加檔案
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- One of the telescope making team member help measuring the center of gravity of the OTA.
- Telescope_CG.jpg (83.93 KiB) 已瀏覽 14259 次
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- The finished OTA, not yet painted, will be ready for star test once the alt-alz mount is ready.
- OTA.jpg (68.82 KiB) 已瀏覽 14259 次
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
Dear Mr. Wah!,Wah! 寫:好幼的木條,中間斷開兩節,用起來真係會心慌慌...
I don't understand why we get to be panic. The struss won't get broken so easily, even if it does, just repair it on site. It takes only few minutes of work.
The real disaster is that the telescope is becoming too heavy that we cannot bring to site. Everything will be meaningless.
It is a real pity if the mirror cannot collect photons from universe so often as it is desired to be.
Best regards
Chan Yuk Lun
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
Dear Wongsir,Wongsir 寫:玉驎兄,
希望這枝全港最大自製望遠鏡能夠在本月底完成.
如果你5月7日帶枝大鏡去太空館sidewalk的話,我一定會去開o下眼界.
Wongsir
14-4-2004
Thanks for your encouragement. The sad thing is, even if we finish everything we most probably cannot arrange aluminize the mirror in time.
So the great telescope will see her first light most probably in June/July.
Now it's already dawn before sunrise, the waiting will soon be over.
Best regards
Chan Yuk Lun
I think using c-8 to see stars at dark site should be happier than reparing large scope there.Chanlunlun 寫: I don't understand why we get to be panic. The struss won't get broken so easily, even if it does, just repair it on site. It takes only few minutes of work.
I think using thicker wood won't be much heavier, but much stronger.
You may also ask more students to help you carrying the telescope!
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
Dear Mr. Wah!,
Under dark sky aperture is king. In Australia, under the brilliance of the milky way, large Magellic cloud and the small Magellic cloud, my 20 inch telescope is far far outperforming a C-14, side by side, not to mention a C-8. If you do think that using a c-8 will be happier than using a 24 incher, just for the sake of saving that little three minutes of work, ( and most probably it wouldn't happen ), then I'm surprised by your judgement.
By the way I never design telescope using more than 2 people to carry. An equipement requires a team to handle with is already a failure.
To me telescope should be enjoyed by many, should be carried by one. A saving of weight of every gram is precious.
Hopefully my logic is understood.
Best regards
Chan Yuk Lun
I've been using my 20 inch Newtonian for 6 years traveling around the world for deep sky observing and the struss using is still thinner the the 24 inch telescope under construction. The struss never broke except once in XingLong, because somebody drop the whole equipment onto the floor. We just fixed it by some gluing tape and the telescope functioned well the whole night. It was a 3 minutes work.Wah 寫:
I think using c-8 to see stars at dark site should be happier than reparing large scope there.
Under dark sky aperture is king. In Australia, under the brilliance of the milky way, large Magellic cloud and the small Magellic cloud, my 20 inch telescope is far far outperforming a C-14, side by side, not to mention a C-8. If you do think that using a c-8 will be happier than using a 24 incher, just for the sake of saving that little three minutes of work, ( and most probably it wouldn't happen ), then I'm surprised by your judgement.
By the way I never design telescope using more than 2 people to carry. An equipement requires a team to handle with is already a failure.
To me telescope should be enjoyed by many, should be carried by one. A saving of weight of every gram is precious.
Hopefully my logic is understood.
Best regards
Chan Yuk Lun
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- 夸克星
- 文章: 3847
- 註冊時間: 週四 09 10月, 2003 21:06
Dear Mr. Wah!,Wah! 寫:USING a 24" telescope is a happy thing, but not REPARING it on site.
Another concern is thin wood sticks can be bent easily, which affects the optical alignment and image quality.
I agree with you that repairing on site is a thing that can drive one crazy. But there is nothing to be repaired.
We are not using wooden sticks, we are using WOODEN STRUSS. While stick bends easily, not for STRUSS. The idea of Sieruss struss is that all the struss is undergoing pure tension or pure compression, there is absolutely no bending, no matter how thin the struss is. The optical alignment is kept perfect collimated regardless the thickness of the struss.
Best regards
Chan Yuk Lun
- david_kmng
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