Alan Johnson wrote:
Greetings all non-loonies,

I have just been reading a small piece about the SUNRISE balloon-based
1m telescope. What it didn't tell me, and what I find puzzling, is how
to stabilise a balloon at 40 kilometres altitude to make it useful for
observing the sun?

It's done by wavefront correlation in the image. So instead of
stabilizing the balloon or the telescope, they are going to use
something similar to image-stabilization in camcorders. For details
see the following links:

http://www.kwasan.kyoto-u.ac.jp/sola...21_Solanki.pdf
http://www.vmebus-systems.com/column...fs/04.2005.pdf
http://www.iac.es/proyect/IMaX/Publi...USproposal.doc

The last one is actually the proposal to NASA from the PIs (principle
investigators) for US support. In the proposal, they explain the
stabilization solution in detail.

--
// The TimeLord says:
// Pogo 2.0 = We have met the aliens, and they are us!