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Chriske
Kijkerbouw Urania
Reged: 08/15/04
Posts: 1939
Loc: Boechout, Belgium
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This mount is a easy to build, but care should be taken to have the upper part as stiff as possible to avoid trembling in mount and scope. Especially for larger scope it will be very difficult to have it vibrationfree.
The bearings are the same as used in a regular Dob. Advantage of this strange looking scope is the eyepiece stay at the same height. The only motion the observer need to do is follow the eyepiece around its Azimut-axis when the scope is moved.
This mount should not be made for long planetary scopes. It is a perfect mount for short scopes. As you can see in the drawing when a longer scopes is used you need a very high rocker. Not only the rocker will get higher but the groundboard must be larger in diameter to. So for longer scopes the mount becomes rather clumsy.
Usage :
1- Small to large telescopes.
2- Reflector.
3- Smaller mounts transportable.
Large image
Large image
Large image
Large image
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Chris
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RossSackett
sage
Reged: 08/17/07
Posts: 322
Loc: Memphis, TN
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Chris,
That is a very interesting design. But shouldn't the counterweight be in-line with the main optical axis? I think that the way you show the weight, it will put the c.g. on the observer's side of the altitude trunnion. This could result in the tube lifting off the far altitude trunnion and bonking the observer on the head.
Fantastic series, by the way!
Ross
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Ross Sackett
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11 scopes currently on the flight line from 4.25 to 18"; 5 pairs of astronomical binocs 35-80mm. My wife suggests that with just one pair of eyes, this might be excessive.
See my scope pix at http://www.flickr.com/photos/8315630@N04/
Carpe noctem!
Amateur astronomer = A mature moon-starer
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Chriske
Kijkerbouw Urania
Reged: 08/15/04
Posts: 1939
Loc: Boechout, Belgium
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Yes indeed....  ... .. silly me. I took the same weight from the 'shelf' I used for the Springfield Pipemount...
I'll correct it.
Thanks Ross.. 
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Chris
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RossSackett
sage
Reged: 08/17/07
Posts: 322
Loc: Memphis, TN
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The pipemount needs the offset to keep the center of gravity over the azimuth axis, centered on the the feet of the base; the dob version doesn't need this offset. I like this springsonian version very much--it should be more stable and have smoother motions than the pipemount version.
Ross
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Ross Sackett
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11 scopes currently on the flight line from 4.25 to 18"; 5 pairs of astronomical binocs 35-80mm. My wife suggests that with just one pair of eyes, this might be excessive.
See my scope pix at http://www.flickr.com/photos/8315630@N04/
Carpe noctem!
Amateur astronomer = A mature moon-starer
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Owen
sage
Reged: 06/21/07
Posts: 353
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Looking at the images - there are two weights - on on each side. That would place the counterweight C of G on the optical axis...
Owen
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RossSackett
sage
Reged: 08/17/07
Posts: 322
Loc: Memphis, TN
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Quote:
Looking at the images - there are two weights - on on each side. That would place the counterweight C of G on the optical axis...
But bending back over the observer's head. Looked at from above, this would pull the c.g. towards the outside of the altitude bearing right in front of the observer. In a dob, the c.g. is best centered on the midpoint of the line connecting the centers of the two alt. trunnions, directly over the azimuth axis.
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Ross Sackett
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11 scopes currently on the flight line from 4.25 to 18"; 5 pairs of astronomical binocs 35-80mm. My wife suggests that with just one pair of eyes, this might be excessive.
See my scope pix at http://www.flickr.com/photos/8315630@N04/
Carpe noctem!
Amateur astronomer = A mature moon-starer
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