Satchmo
13-09-2007, 10:10 AM
As an example in lighter technology check out a photo of my 12" travel scope with a 1.1" thick primary.
I built this little scope in 4 days prior to the 2002 solar eclipse as I wanted a backpack scope to take on a bus to SA.
The top end ( minus focuser and finder ) nested into the mirror box which nested into the mount. The side bearing went into my backpack and the poles on the outside. I could easily carry the rest in one hand as it became a 'suitcase'.
There is no heavy steel mirror cell. The mirror is attached and floats on a 7" diameter ring of Velcro , on a lightweighted 1/2" ply triangular back plate. The poles are 16mm OD The rocker box and base weigh 3kg. As a party trick I can balance the complete scope on the palm of my hand :), yet I've never gone out to observe and found its lightness detrimental to my observing experience.
I enjoy its minimal thermal mass to a heavy traditional truss. It has often showed textbook airy discs within 30 minutes of setting up.I think there is always room for a little compromise in construction in following Kreiges Dobsonian book, if you are prepared to lose a bit of high wind resistance.
I built this little scope in 4 days prior to the 2002 solar eclipse as I wanted a backpack scope to take on a bus to SA.
The top end ( minus focuser and finder ) nested into the mirror box which nested into the mount. The side bearing went into my backpack and the poles on the outside. I could easily carry the rest in one hand as it became a 'suitcase'.
There is no heavy steel mirror cell. The mirror is attached and floats on a 7" diameter ring of Velcro , on a lightweighted 1/2" ply triangular back plate. The poles are 16mm OD The rocker box and base weigh 3kg. As a party trick I can balance the complete scope on the palm of my hand :), yet I've never gone out to observe and found its lightness detrimental to my observing experience.
I enjoy its minimal thermal mass to a heavy traditional truss. It has often showed textbook airy discs within 30 minutes of setting up.I think there is always room for a little compromise in construction in following Kreiges Dobsonian book, if you are prepared to lose a bit of high wind resistance.