Thanks for your comments David.
I have some photos scattered through my web site
Picture of the mounting + 70mm f6.3 APO
http://tinyurl.com/9j7u9ey
Few pictures of me with the equipment (less detailed) on the motu (little island) at Tatakoto taken by Geoff Sims or Bengt Alfredsson at the top of this page :
http://joe-cali.com/eclipses/PAST/TSE2010/joe.html
The equipment developed gradually over a ten year period of eclipse chasing. I have a whole article describing the evolution of my gear.
Basically it wasn't a question of whether I could get away with carrying the weight, it was that I didn't enjoy lugging it around and I had to cut it down so I could also enjoy the travel associated with these trips.
http://joe-cali.com/eclipses/EQUIPME...Evolution.html
Basically the whole mount is designed specifically for solar eclipse observing and flight portability.
Every component of the mount and tripod is constructed from hollow tubes or thin struts. Strength and bulk only where required.
The single arm fork can be slid back and forth transverse to the RA axis to balance the load around the RA axis thereby eliminating the need for any counterweights.
The drive is a very small diameter not very accurate worm drive driven by a small step motor and a simple driver circuit. Accurate enough for any solar event but definitely not for long exposure astrophotography. With a max exposure of only a few seconds for the outer corona, you don't need an accurate drive for a solar eclipse. However a drive that keeps the sun centered is a great convenience.
It's strong but so light the payload can tip it so I often hang weight off the tripod under the head or more commonly use rubber bands to attach bottles of water to each leg to stabilize it. These can of course always be purchased at or near destination and not carried on the airline. In the photo on the China page, I was about to pack up and removed the water bottles before taking the photos.
Of more importance is that an equatorial drive will keep the image correctly rotated which makes stacking vastly easier. Whilst you can rotate and align images from an alt-az mounted system, Moon and the corona are moving at different rates. Background stars down to mag. 6 to 7 are visible in my longer exposures but not in the short ones. Following each solar eclipse, the solar eclipse mailing list is full of people asking how to align alt-az acquired images. It isn't easy and many give up in frustration.
Cheers
Joe