World's Largest Airborne Telescope Delivered

Thurog writes "SOFIA, the Stratospheric Observatory for Infrared Astronomy, has received the telescope built in Germany by the German Space Agency, DLR. SOFIA consists of a Boeing 747SP aircraft modified by L-3 Communications Integrated Systems to accommodate a 2.5 meter reflecting telescope. When on a mission, it will soar through the higher levels of the atmosphere, thereby overcoming the fact that atmospherical humidity filters most of incoming infrared radiation. It's not the first airborne telescope, but so far the most powerful."

Comments

Re:Why not use a balloon?

[foolish]

Err, It's really heavy that's why. Suspesion, primary mirror and secondary mirror assemblies all weigh about 31,500 lbs. Which means you need about 492187.5 ft^3 of helium.

And to date, there are not highly sterrable, controllable ballons in operation that can oeprate at those heights (41,000 ft). Those companies pitching the 'new' blimp concepts just aren't there yet.

--foolishone

Re:Why not use a balloon?

[HorsePunchKid]

I don't think that obstruction of view would be too big of a factor. The high-alititude balloons that I've seen photos of seem to generally be very large (need room for gas to expand into), but also extremely tall. The only constraint would be that you couldn't point your telescope within, say, 15 degrees or so of straight overhead. But foolish's point about it being very heavy is probably the main factor. BOOMERANG was relatively small. Check out this picture of the gondola with the telescope inside. The whole thing can't be more than 6m or 7m tall, and the main mirror only weighed about 12kg.