早期的香港DIY有電跟的赤道儀
- PeterPeter
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早期的香港DIY有電跟的赤道儀
當上門打聽天文鏡的到貨進展時,無意中發現到這個早期的香港DIY有電跟的赤道儀.
聽老闆講它的蝸齒有成三百多個齒. 真係想知到它可否與現代中型的mount較量一下.
聽老闆講它的蝸齒有成三百多個齒. 真係想知到它可否與現代中型的mount較量一下.
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最後由 PeterPeter 於 週四 11 3月, 2010 17:01 編輯,總共編輯了 1 次。
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- 來自: HUBEI WUHAN
The worm gear has 360 teeth, but the worm is double-thread. Thus the gear ratio is 180:1.laoshuerhao 寫:会不会涡轮齿的模数太小,使用的时候怕力量太大承受不起。具体的还是要看承载多大的镜子决定!
I still have 3 of these gears. I believe I have purchased at least 15 or 18 of them in the 1970's.
These were available from a kiosk in Canton Road, for about $20 a set.
PTS
Re: 早期的香港DIY有電跟的赤道儀
I am interested in where did you find this?PeterPeter 寫:當上門打聽天文鏡的到貨進展時,無意中發現到這個早期的香港DIY有電跟的赤道儀.
聽老闆講它的蝸齒有成三百多個齒. 真係想知到它可否與現代中型的mount較量一下.
From the photos, the polar axis is based on my earlier design : using bronze bushing as bearings, and a split bronze bushing as the clutch.
This must belong to one of my old friends.
PTS
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At those days, we were mostly using synchronized motors. The popular one has a rate of 1/4 rpm, and, with a 2:1 gear, the 180:1 worm gear is perfect for solar rate tracking.HK.Raymond.Tse 寫:This type of DIY "precision" mount powered by AC motor was the dream mount in my era of middle school life. Only seen on paper in the news bulletins of local astro societies.
Just a dream at that time, however, which can only be materialized after 30 years.
Raymond Tse
However, to make it tracking at sidereal rate, we have to built our own variable frequency power supply unit.
local 200 volt ac at 50 hz is first converted to dc, which is then fed to an inverter to convert back to AC, but this time with control on the output frequency. The control is not much, just +/-10%. Within this range of control, we can preset the sidereal, solar, lunar and VARIABLE rates, as well as SLEW which is just the +/-10% maximum (unlike these days of 200X slew!)
PTS
PTS, I still remember the days when you helped us design and build a similar mount for our secondary school astro club. We went to Canton Road to search for the parts (worm gears, motors etc) and get the materials. I can vividly recall the sketches of the mount design with bush bearing and clutches. Still think it is a very good design. Unfortunately I never witness the operation of the mount since by that time I already went overseas to further my study.PTS 寫:At those days, we were mostly using synchronized motors. The popular one has a rate of 1/4 rpm, and, with a 2:1 gear, the 180:1 worm gear is perfect for solar rate tracking.HK.Raymond.Tse 寫:This type of DIY "precision" mount powered by AC motor was the dream mount in my era of middle school life. Only seen on paper in the news bulletins of local astro societies.
Just a dream at that time, however, which can only be materialized after 30 years.
Raymond Tse
However, to make it tracking at sidereal rate, we have to built our own variable frequency power supply unit.
local 200 volt ac at 50 hz is first converted to dc, which is then fed to an inverter to convert back to AC, but this time with control on the output frequency. The control is not much, just +/-10%. Within this range of control, we can preset the sidereal, solar, lunar and VARIABLE rates, as well as SLEW which is just the +/-10% maximum (unlike these days of 200X slew!)
PTS
There are really lots of old friend here.anguslau 寫:PTS, I still remember the days when you helped us design and build a similar mount for our secondary school astro club. We went to Canton Road to search for the parts (worm gears, motors etc) and get the materials. I can vividly recall the sketches of the mount design with bush bearing and clutches. Still think it is a very good design. Unfortunately I never witness the operation of the mount since by that time I already went overseas to further my study.PTS 寫:At those days, we were mostly using synchronized motors. The popular one has a rate of 1/4 rpm, and, with a 2:1 gear, the 180:1 worm gear is perfect for solar rate tracking.HK.Raymond.Tse 寫:This type of DIY "precision" mount powered by AC motor was the dream mount in my era of middle school life. Only seen on paper in the news bulletins of local astro societies.
Just a dream at that time, however, which can only be materialized after 30 years.
Raymond Tse
However, to make it tracking at sidereal rate, we have to built our own variable frequency power supply unit.
local 200 volt ac at 50 hz is first converted to dc, which is then fed to an inverter to convert back to AC, but this time with control on the output frequency. The control is not much, just +/-10%. Within this range of control, we can preset the sidereal, solar, lunar and VARIABLE rates, as well as SLEW which is just the +/-10% maximum (unlike these days of 200X slew!)
PTS
Which school are you from?
PTS
QESPTS 寫:There are really lots of old friend here.anguslau 寫:PTS, I still remember the days when you helped us design and build a similar mount for our secondary school astro club. We went to Canton Road to search for the parts (worm gears, motors etc) and get the materials. I can vividly recall the sketches of the mount design with bush bearing and clutches. Still think it is a very good design. Unfortunately I never witness the operation of the mount since by that time I already went overseas to further my study.PTS 寫:At those days, we were mostly using synchronized motors. The popular one has a rate of 1/4 rpm, and, with a 2:1 gear, the 180:1 worm gear is perfect for solar rate tracking.HK.Raymond.Tse 寫:This type of DIY "precision" mount powered by AC motor was the dream mount in my era of middle school life. Only seen on paper in the news bulletins of local astro societies.
Just a dream at that time, however, which can only be materialized after 30 years.
Raymond Tse
However, to make it tracking at sidereal rate, we have to built our own variable frequency power supply unit.
local 200 volt ac at 50 hz is first converted to dc, which is then fed to an inverter to convert back to AC, but this time with control on the output frequency. The control is not much, just +/-10%. Within this range of control, we can preset the sidereal, solar, lunar and VARIABLE rates, as well as SLEW which is just the +/-10% maximum (unlike these days of 200X slew!)
PTS
Which school are you from?
PTS
I took up this name later. My chinese name is 劉劍明. You may not remember me since I am very low profile. You probably remember people like 劉育港,伍學斌 etc. We had a quite large and high profile club among the secondary schools at that time. Still rememer we organised the first Joint School Astronomy Exhibition (~1975/6 I think?). I believe this event has disappeared now.PTS 寫:Yes, I have many friends from QES, but I cannot remember you with this name. Are you the heart specialist?
PTS
I see.anguslau 寫:I took up this name later. My chinese name is 劉劍明. You may not remember me since I am very low profile. You probably remember people like 劉育港,伍學斌 etc. We had a quite large and high profile club among the secondary schools at that time. Still rememer we organised the first Joint School Astronomy Exhibition (~1975/6 I think?). I believe this event has disappeared now.PTS 寫:Yes, I have many friends from QES, but I cannot remember you with this name. Are you the heart specialist?
PTS
I mistakenly thought you were 劉育港. haha.
What are you doing now. May be you can send me an email to keep privacy.
PTS
I haven't seen him for many years as well. I heard he still have interest in this hobby. But probably too busy with work. I am already retired. So I have more time to pick up this old hobby again.PTS 寫:I see.anguslau 寫:I took up this name later. My chinese name is 劉劍明. You may not remember me since I am very low profile. You probably remember people like 劉育港,伍學斌 etc. We had a quite large and high profile club among the secondary schools at that time. Still rememer we organised the first Joint School Astronomy Exhibition (~1975/6 I think?). I believe this event has disappeared now.PTS 寫:Yes, I have many friends from QES, but I cannot remember you with this name. Are you the heart specialist?
PTS
I mistakenly thought you were 劉育港. haha.
What are you doing now. May be you can send me an email to keep privacy.
PTS
That is good news. You should find time to help in our star parties.anguslau 寫:I haven't seen him for many years as well. I heard he still have interest in this hobby. But probably too busy with work. I am already retired. So I have more time to pick up this old hobby again.PTS 寫:I see.anguslau 寫:I took up this name later. My chinese name is 劉劍明. You may not remember me since I am very low profile. You probably remember people like 劉育港,伍學斌 etc. We had a quite large and high profile club among the secondary schools at that time. Still rememer we organised the first Joint School Astronomy Exhibition (~1975/6 I think?). I believe this event has disappeared now.PTS 寫:Yes, I have many friends from QES, but I cannot remember you with this name. Are you the heart specialist?
PTS
I mistakenly thought you were 劉育港. haha.
What are you doing now. May be you can send me an email to keep privacy.
PTS
You are also welcome to join my observations (asteroid occultation, stellar spectroscopy, etc) at Hokoon.
My contact : aptspoon@cityu.edu.hk
PTS
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