James Webb Space Telescope, information, updates and discussion Options

[Redstone]

The manufacture of the JWST mirror blanks has now been completed.

Despite this milestone, the fate of JWST is still somewhat precarious, because although the scientific bang from the telescope is expected to be huge, the bucks required have increased to a staggering $4.5 billion. A Space.com article on the squeeze in NASA's space-based astronomy plans gives some background.

The JWST home page can be found here.

The Space Telescope Science Institute, which runs Hubble, also has a site here. As does ESA.

[elakdawalla]

One issue I hadn't appreciated until recently is how the design of JWST isn't exactly optimized for solar system observations. It has to keep the sun shield between it and the sun, but the telescope points at right angles to the sun shield. So it can't point at things when they are at opposition, only at geometries roughly tangent to JWST's orbit. Doesn't matter as much for resolution on distant targets but makes a big difference for Mars and asteroids, and limits when things can be observed.

[SteveM]

One issue I hadn't appreciated until recently is how the design of JWST isn't exactly optimized for solar system observations. It has to keep the sun shield between it and the sun, but the telescope points at right angles to the sun shield. So it can't point at things when they are at opposition, only at geometries roughly tangent to JWST's orbit. Doesn't matter as much for resolution on distant targets but makes a big difference for Mars and asteroids, and limits when things can be observed.

Thanks for pointing that out. A positive aspect of that geometry is that JWST can only observe stars six months apart when the line of sight is tangent to the Earth's orbit. That's the ideal geometry for stellar parallax measurements. With appropriate analyses of the stars' point spread functions, JWST might get up to the level of Gaia's parallax measurements.