The Billion-Dollar Telescope

dcmeserve writes "As in all science, astronomers are ever searching for better technology to aid in their task. But when it comes to telescopes, nothing beats sheer bulk of light-gathering capability. This article gives a brief overview of the top contenders for the next leap forward, including a 100-meter behemoth that is expected to run $1 billion."

Comments

Re: The Billion-Dollar Telescope

[nsebban]

In fact, it's "The Billion-Euros Telescope" which means about 20% more.

Meanwhile on the cheap side...

[ackthpt]

I was just talking with someone a few nights ago about Univerisity of California Santa Cruz, seems they're going to build a radio telescope on the cheap side, good for them. A bunch of smaller dishes over a wide area. Probably eventually hooked up to that el-cheapo Athlon studded supercomputer they built.

Necessity may be the mother of invention, but when you've got a lean budget you innovate.

BTW, there's this interesting other stuff in the news about Aussies seaching the heavens for likely places to host another earth.

Obligatory filching of Galaxy Song lyrics: So remember, when you're feeling very small and insecure,
how amazingly unlikely is your birth,
Pray that there's intelligent life somewhere up in space,
because there's bugger all down here on Earth.

Re:Too much interference

[FTL]

> ISS should have a giant telescope mounted on it.

Negative.

• ISS shakes. It's got humans inside it who won't sit still. If you want to do deep-field astronomy you want to be able to point at an object and sit there collecting light for hours or days.
• ISS leaks air and other gasses. It is surrounded by a gas bubble. Any telescope in the area would have these gasses condensing on it's mirror.
• ISS is in a nasty orbit. The orbit is highly inclined so that Russian vehicles can reach it (thank goodness, given the recent Shuttle grounding). But the trade off is that it is much more expensive to put stuff on ISS than to put it in a more equitoral orbit (where Hubble is).
• ISS passes through the South Atlantic Magnetic Anomaly on a regular basis. This is a nasty area which causes problems for sensitive equipment. A more equitorial orbit would largely avoid this area and allow a telescope to capture faiter images before having to safe itself.
• ISS is too low. At such low altitudes you've got a lot of atomic oxygen from the upper atmosphere. Atomic oxygen is very reactive and would ruin your mirrors quickly.

Re:Wouldn't $1B be better spent on a space telesco

[Scott Ransom]

Not really. With the rise of adaptive optics, ground-based telescopes are increasingly able to achieve diffration-limited or near-diffraction-limited resolution in the optical and (in particular) the near-IR (which is of crucial importance for cosmology -- the current "Hot" area of astronomy).

Once you hit that physics-limited level of resolution (which has been the true advantage of HST), the gains come from light-gathering ability. This is where ground-based telescopes clean up. The $$/area is much lower (i.e. better) for ground-based telescopes. And the upkeep costs are much smaller as well. Space is expensive.

When you can have a telescope with near-diffraction limited resolution and 10-1000 times the light gathering ability of a space-based telescope of the same cost, astronomer's will choose that guy any day.

Note: IAAA (I am an astronomer)

Re:Too much interference

[elh102]

It's a shame Hubble is our only orbiting telescope.

There's more to the electromagnetic spectrum than visible light you know. The Hubble Space Telescope is only one of NASA's four orbiting "Grand Observatories". Here are links to info about the other telescopes.

• Chandra X-Ray Observatory
• Compton Gamma Ray Observatory
• Spitzer Space Telescope

Ground vs. Space summary

[ChrisDolan]

Several people have commented that the money may be better spent on a space telescope. Here's why that may not be true:

Advantages of space:
* Extremely low light pollution and air absorption. This means you can see very dim things that may not be ever visible from the ground.

Advantages of ground:
* Initial cost is about 100-1000 times cheaper for same-sized primary
* Repairs and routine maintenance are possible without a $250 million shuttle launch
* Newer technology is possible, since it's less risky. Hubble uses a lot of electronics from the early 1980s.

Hubble cost $1.5 billion initially plus $0.25 billion per year (http://hubble.nasa.gov/faq.html) for a 2.5-meter telescope.

Since light-collecting power goes as the square of the diameter, a 100-meter telescope has 1600 times the light collecting ability of Hubble. So, if the celestial objects of interest are not background-limited, you can get the same quality image in 1 minute that would take Hubble a whole day to acquire.