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Fraser
2006-Jun-19, 07:29 PM
When it comes to astronomy, large telescopes rule. But if you can get your instrument into space, you bypass the atmosphere that blurs sensitive data. Unfortunately, the cost of launching observatories into space is beyond the budget of most researchers. One possible strategy is to install powerful observatories instruments onto high altitude airships, which can float above most of obscuring atmosphere. The view from the high atmosphere is almost as good as actually being in orbit, and it can be had for a fraction of the price of flying a telescope into orbit.

Read the full blog entry (http://www.universetoday.com/2006/06/19/airship-observatories-could-give-the-best-view/)

antoniseb
2006-Jun-19, 07:51 PM
These would be excellent. The article talks about using it for small insturments, but I wonder how large a blimp we could build for this purpose. Could we launch a ten-meter telescope with something like this?

RAFesen
2006-Jun-19, 09:09 PM
Yes one could, in principle, lift telescopes with mirrors larger than just 1/2 - 1 meters but
weight is the main factor limiting just how large one could go. At 85,000 ft, one
is above 98% of the atmosphere so if one could (somehow) build a very lightweight
2 - 3 meter diameter mirror telescope AND point it accurately and track targets (stars, etc.)
then one would essentially have a "Hubble-junior" like observatory - at a tiny fraction
of the cost of a similar size space observatory facility.

As to a 10 meter...well, let's first wait for a 1 meter telescope and see how it all goes. ;-)
But the advantages for developing such a high-altitude observatory are large indeed!

antoniseb
2006-Jun-19, 10:24 PM
Thanks for responding Dr. Fesen.

I was extrapolating, and not so much saying that the first one should be huge, but rather looking ahead to what it could ultimately be. We could imagine a facility in which the lifting body was huge and had a cubic kilometer of Helium. Expensive? yes. Compared to the cost of Hubble? maybe not.

parallaxicality
2006-Jun-20, 07:22 AM
It might be the best option for observing the region between Mercury and the Sun.

suitti
2006-Jun-20, 02:22 PM
Mixed units drive one nuts. 85 kft = 85,000 feet = 16 miles = 26 km. Next we'll hear that it's a mega-inch. The US Congress mandated the metric system in the 1800's. That's plenty of time.

ORSkywatcher
2006-Jun-20, 05:06 PM
This type of project is very doable. The Southern Oregon Balloon Satellite group launched an eight pound payload to 101,620 ft on May 21, 2006. This was our first attempt and we were very successful. We recovered the payload and our data and images from the flight. With just a 3MP camera we took very good images at altitudes up to 95,000 ft. Unfortunately our battery for the camera timer froze and we did not take any pictures after that point. The best thing about this is that we did this for less than $1000.00 US. If you are interested in seeing the images we took check out our yahoo groups page at:

http://groups.yahoo.com/group/BalloonSat/

Clear skies and keep dreaming!

antoniseb
2006-Jun-20, 05:21 PM
The best thing about this is that we did this for less than $1000.00 US.

That's very cool. How much extra weight for a heater for the battery?

RAFesen
2006-Jun-20, 07:23 PM
Mixed units drive one nuts. 85 kft = 85,000 feet = 16 miles = 26 km. Next we'll hear that it's a mega-inch. The US Congress mandated the metric system in the 1800's. That's plenty of time.

If one listed an airship's cruising altitude as 26 km, few Americans would fully grasp just how high up that is. Plus flight levels for most countires (except for China, Russia, Mongolia and a few others) are measured in feet (e.g., 27,000 ft up is flight level 270 - which is a common flying altitude over Europe). Moreover, across most of the globe flights traveling to the east cruise at odd thousand feet flight levels (e.g., FL 270, 290, etc.) while flights going westward cruise at even thousand feet flight levels. So you see, listing an airship's altitude in feet while quoting mirror diameters in meters maybe isn't so crazy after all.

The flying public, both in the US and abroad, might then understand that placing a telescope up at say 70,000 ft amounts to flying it simply at about twice the altitude of that of a commerical airliner flight - and yet by doing so one can get image quality that can rival that obtained from far more expensive satellite missions.

Igor
2006-Jun-20, 11:34 PM
Bringing back the airship might be an interesting idea as a less complex and
expensive alternative to space tourism technology. But at the edge of space
you leave most of the atmosphere below. In such rarified air could helium
provide sufficient lift to float an airship and the crew and the passengers
on board? Any comments, folks?
Igor

selden
2006-Jun-21, 11:28 AM
Helium filled balloons with volumes of tens of millions of cubic feet have caried experimental apparatus, usually telescopes of various types, as high as about 130,000 feet. Airships have a lot more structural weight and can't get as high.
http://topweb.gsfc.nasa.gov/balloon/science.html
http://www.gsfc.nasa.gov/news-release/releases/2002/h02-163.htm

tdvance
2006-Jun-21, 03:18 PM
I wonder if these airship telescopes would be cheap enough that one (or more) could be funded by amateur astronomers who pay for observation time. That would provide some impetus to build them!

Todd