Alan Boyle (who is on his way to check out the rocket racing exhibition in New Mexico), talks about advances in adaptive optics, with a spectacular picture of a sunspot.

In fact the advances in adaptive optics really call into question the need for NASA to do a Hubble service mission. We already have ground based telescopes that are producing images that rival even that great space observatory. With all other things beginning to equal out it is going back to an old saying in astronomy, "aperture is everything." If space based observations are going to be able to leap ahead of their terrestrial counterparts then a bigger telescope is going to be needed and the James Webb NGST is the direction to go.

On the other hand I believe there are certain spectrums where space based observations still reign supreme. In those cases a telescope the size of Hubble is not really warranted but instead a flotilla of smaller highly specialized telescopes, some even the size of a suitcase, would be adequate. I think this would be a possible source of revenue for a cheap and routine space access service. We would probably see a proliferation of telescope sats being constructed with little more then radio shack parts and expected lifetimes of weeks or months. Cheap access to space could provide a great appeal for many researchers to hoist their own telescope up into orbit instead of waiting in line with everyone else for a few precious moments of observation time on a great observatory.

"In fact the advances in adaptive optics really call into question the need for NASA to do a Hubble service mission. We already have ground based telescopes that are producing images that rival even that great space observatory."

This is quite simply false, but because the subject is obscure and complex, one could expect a lot of ignorance about it.

Ground-based astronomy cannot, and never will, be able to do the kinds of things that Hubble can do right now because of the laws of physics. First, no matter how big the aperture, or how good the adaptive optics, a ground-based telescope will never see in the ultraviolet wavelengths that Hubble does for the simple reason that UV does not reach the ground.

Second, no matter how big the aperture, or how good the optics, a ground-based telescope will never be able to do the kinds of deep background investigations that Hubble can do for the simple reason that even the darkest night sky on earth has a lot of photos flying around that will overwhelm the detectors searching for extremely faint objects. You can have the darkest sky on earth and the biggest telescope you can build, and it will still be swamped by noise.

Hubble does not have that kind of problem.

Ground-based telescopes have come to rival Hubble in some areas that were Hubble's exclusive domain 10+ years ago. But those areas were limited by available technology, not physical laws.

And solar astronomy (the subject of this article) is significantly different than other kinds of astronomy. So it is not really possible to equate advances in that field to other areas of astronomy. There's a big difference between looking at an overwhelming star only eight minutes away and searching for the origins of dark matter 15 billion years away.

I suggest that if you want to continue to opine on this subject and actually be knowledgeable, you should talk to an astronomer. Not all of them worship at the altar of Hubble, but they all acknowledge its capabilities.

There was an interesting and informative presentation at Fermilab a few years ago on the HST. The speaker described the advantages over ground-based scopes, giving even more technical detail. A recording of the presentation (with coordinated slides, viewable using Real Player in your web browser on Windows or OS X) is available at the the FNAL web site. There are lots of other interesting talks there; see the Fermilab Colloquium page as well more specialized talks.

I'll second William Berger.

There's a reason the uv spectrum has a sub-spectrum called the 'vacuum ultra-violet'.

If this wasn't the case, I could sell several thousand dollars of high-vacuum pumps and bits.

But I want to stress that it is not _just_ the UV spectrum that Hubble can see. And it is not _just_ faint objects that Hubble can see. It has a pretty good wide field of view as well. You can get a wide field of view on a ground-based scope, but you don't get the same kind of fidelity as you get from Hubble. It provides a high quality over a large field, whereas ground-based scopes give you one or the other. For instance, adaptive optics can give you good point sources, but they don't work well on nebulae, so if you want a good quality image of stellar formation, a ground-based telescope won't work.

I'm now hearing a new myth associated with the ESA Herschel IR telescope that is in the final stages of construction. That myth is that Herschel's mirror is bigger, lighter, and therefore "better" than Hubble's. Although it is bigger, because it is designed for the IR spectrum, it does not require the same kind of high precision as Hubble. Hubble is old, but people who know optics recognize that it is a truly amazing piece of engineering. Herschel, on the other hand, will do things that Hubble cannot.

These instruments are complementary. They all help each other. And that is part of the equation when trying to determine Hubble's value.

William,

Yes, I realize I spoke in generalized terms and I know you brainy types just love to take those opportunities to point out specifics and details that bolster your own perceptions of how smart you are. I did not get specific since I figured that when I say things like, “ground based scopes can provide imagery that rivals Hubble” that you’d understand those areas I am talking about without having to spell it out for you since generally someone will either really like astronomy and will know such things already or could care less about astronomy and would say, “uhhh whatever”. I understand that there are things that exist in our world such as, atmospheres, and that it is physically impossible to see certain wavelengths from the ground. I’d like you to perhaps talk to someone at the ESO Paranal Observatory and tell them there telescopes can’t take high resolution deep space and diffuse gas imagery.

You've actually just ended up going right back to my original point of contention and in effect actually strengthening my argument to some degree that, while Hubble is nice, it doesn't hold such a high value as to require a Shuttle servicing mission. So, I will take this opportunity to say, yes I am not going to do a break out of the specifics of what Hubble can and can't do because I am not equipped to do so. I should have put more emphasis on the notion that Shuttle needs to be decommissioned sooner then later and settling the Hubble servicing mission issue is one way to bring that decomm a step closer. It was just an opinion, not necessarily an opportunity for you to pull out a measuring stick and show me how much smarter you are about looking at fuzzy points of light in the sky then I am.

I also believe I’ve made a more mature point towards the end of my original statement in acknowledging that there are certain wavelengths that benefit observation from space. Which you just completely ignored and went straight to the, “oh you didn’t say something the right way so your ignorant” phase of your argument. I am not certain how I could have put more emphasis on where I believe cheap access to space could fulfill a particular need. I know that we need to find several answers to the question of, “why do we need to go to space” and was attempting to put an objective out there that would provide a purpose for such a capability.

Also, It looks like we are going to be getting a heavy lifter here sometime in the future with impressive weight and size capabilities. Just imagine a space telescope large enough to fill out a 30ft payload fairing and 100t of mirror and instruments on board. If we took advantage of that I’m sure we’d all be going, “Hubble what?”

"Yes, I realize I spoke in generalized terms and I know you brainy types just love to take those opportunities to point out specifics and details that bolster your own perceptions of how smart you are."

Wow, awfully defensive there...

Sorry, but you really stirred my ire with your response. I'm gonna eat your spleen!! I'm gonna eat your heart!! I'm gonna eat your blood vessels and suck out the blood!! FREAK!! In fact, I'm gonna pick at what you said some more...

Quote: "But I want to stress that it is not _just_ the UV spectrum that Hubble can see. And it is not _just_ faint objects that Hubble can see. It has a pretty good wide field of view as well."

First off, Hubble was primarily built as a optical and infared observatory; ultraviolet observations are not its primary forte. The Extreme Ultraviolet Explorer was a dedicated satellite used for ultraviolet observations and was plowed into the atmosphere after it met all its primary science goals and then some. Even though that sat has been brought down it produced reams of good data that is still being slowly worked through to do this day.

Secondly, associating the aspects of wide field of view with deep field astronomy is a completely oxymoronic statement. When looking at the maximum of Hubbles deep field distances your only looking at a fraction of a speck of dirt on the tip of your thumb held out at arms length from your face. In fact, it would take 600,000 years of continuous observations with Hubble at its maximum viewing distance to examine the entire universe around us. While I understand that Hubble is able to see 10x farther back in time then any current ground base telescope it is not impossible to build something in the future to match its performance. Europe is putting together plans for a 100m ground based scope that would rival any deep field view that Hubble has to offer.

So put that in your space telescope and smoke it, CHUMPY!!

"So put that in your space telescope and smoke it, CHUMPY!!"

You're a loon.