Replacement to Hubble

[dushyant]

Even as HST is completing 25 years in April, there is no plan for a visible spectrum space telescope of next generation. Is it because ground based telescopes can do an equally good job now, or have we reached the physical limit to magnification?

If one looks at APOD, almost all the deep space photos are still from HST, so there is still a need for it.

Dushyant

[geckzilla]

I believe it's because telescopes are made with money and space agencies are allotted a finite amount. I know NASA's money is being spent on JWST along with various other projects. There are several ground based telescopes under construction and they can be very good but along with the usual limitations the atmosphere creates they are more limited than a space telescope in the amount of sky they can look at since the Earth gets in the way. You can ask any astronomer if we need another space telescope and the answer will nearly always be yes (What kind of astronomer says no? Radio astronomer?)... and then the nigh invariable reason not to build it will be financial.

[Ann]

I'm so going to miss Hubble's ultraviolet capabilities!

Ann

[BDanielMayfield]

Even as HST is completing 25 years in April, there is no plan for a visible spectrum space telescope of next generation. Is it because ground based telescopes can do an equally good job now, or have we reached the physical limit to magnification?

If one looks at APOD, almost all the deep space photos are still from HST, so there is still a need for it.

Dushyant

With new adaptive optics that can change mirror shapes many times a second to counteract atmospheric effects ground based telescopes are catching up to Hubble. And a few truely gigantic, 30 meter class ground telescopes are moving past planing phases into site prep, etc.

That being said, it still would be good to to have a visible/near ultraviolet HST upgrade, but at present who has the means to launch and service something as large as, or preferably larger than the HST? Cue the sound of crickets ...

Bruce

[Chris Peterson]

Even as HST is completing 25 years in April, there is no plan for a visible spectrum space telescope of next generation. Is it because ground based telescopes can do an equally good job now, or have we reached the physical limit to magnification?

As others have noted, it's mainly about resources. Given the money available for space telescopes (and we can certainly argue there should be more, but there isn't and that's pretty much the situation we have to accept), visible light isn't the right place to spend it. Most of the interest in visible light imaging these days is at small image scales- looking at distant galaxies and nearby stellar systems- and for that purpose ground based telescopes operate at much higher resolution than anything we can afford to put into space. So it makes good sense to focus on parts of the spectrum that are blocked by the Earth's atmosphere. That means UV or IR, and of these two IR is by far the most useful scientifically. So there we are.