by NGC3314 » Thu Feb 18, 2016 2:58 pm
I'm going to have to argue with Chris on some of those points. There are indeed pushes for bigger optical/UV instruments
(sample) - but to significantly improve on Hubble's performance, it has to be a big jump and a flagship-class mission that comes up in the budget only every 15-20 years (so, have it lined up on the runway when WFIRST is launched...) I strenuously object to the implication often found in instrument descriptions that we need them for a few key observations and then it's basically done - in every case of the Great Observatory-class missions, the unexpected (which builds up over time, and even accelerates as the community learns to do more challenging things and gets comfortable with large-scale programs) has been a greater legacy. Hubble Deep Field, the Andromeda survey, COSMOS survey of 2 square degrees - none of these would have been done in the first few years as people scrambled for low hanging fruit.
And I'm not convinced that
visible-light adaptive optics is at the point to replace HST's optical capability. It may be possible, modulo needing to deconvolve PSF wings and the complications that introduces for spectroscopy, but I have not seen actual results yet matching <0.1" resolution for long exposures of faint targets shoreward of 0.8 microns or so. (Willing to see new data, of course).
Yes, a nerve!
I'm going to have to argue with Chris on some of those points. There are indeed pushes for bigger optical/UV instruments [url=http://cor.gsfc.nasa.gov/copag/aas_jan2015/129-BJWST_Path_Ahead_V6.pdf](sample)[/url] - but to significantly improve on Hubble's performance, it has to be a big jump and a flagship-class mission that comes up in the budget only every 15-20 years (so, have it lined up on the runway when WFIRST is launched...) I strenuously object to the implication often found in instrument descriptions that we need them for a few key observations and then it's basically done - in every case of the Great Observatory-class missions, the unexpected (which builds up over time, and even accelerates as the community learns to do more challenging things and gets comfortable with large-scale programs) has been a greater legacy. Hubble Deep Field, the Andromeda survey, COSMOS survey of 2 square degrees - none of these would have been done in the first few years as people scrambled for low hanging fruit.
And I'm not convinced that[i] visible-light[/i] adaptive optics is at the point to replace HST's optical capability. It may be possible, modulo needing to deconvolve PSF wings and the complications that introduces for spectroscopy, but I have not seen actual results yet matching <0.1" resolution for long exposures of faint targets shoreward of 0.8 microns or so. (Willing to see new data, of course).
Yes, a nerve!