Date: 10/06/2016 21:48:22
From: mollwollfumble
ID: 905932
Subject: If I ruled the JWST?
If you had complete control over the space objects photographed by the upcoming James Webb Space Telescope, what would you photograph?
If you had complete control over the space objects photographed by the upcoming James Webb Space Telescope, what would you photograph?
mollwollfumble said:
If you had complete control over the space objects photographed by the upcoming James Webb Space Telescope, what would you photograph?
The bit’s of Apollo missions left on the moon :)
mollwollfumble said:
If you had complete control over the space objects photographed by the upcoming James Webb Space Telescope, what would you photograph?
mollwollfumble said:
mollwollfumble said:
If you had complete control over the space objects photographed by the upcoming James Webb Space Telescope, what would you photograph?
Webb’s angular resolution, or sharpness of vision, will be the same as Hubble’s, 0.1 arc-seconds, not any better. The JWST will be worse than Hubble un UV but better in IR (i.e. cool objects like those seen by Spitzer). The larger mirror size means that JWST will be able to see much fainter objects than Hubble.
Would be nice to get a shot of Neptune while it’s vortex is out.
pommiejohn said:
mollwollfumble said:
If you had complete control over the space objects photographed by the upcoming James Webb Space Telescope, what would you photograph?
The bit’s of Apollo missions left on the moon :)
For a little background info..
http://jwst.nasa.gov/comparison.html
“This larger light collecting area means that Webb can peer farther back into time than Hubble is capable of doing”Course there is always Sag A.
Postpocelipse said:
Would be nice to get a shot of Neptune while it’s vortex is out.
mollwollfumble said:
Postpocelipse said:
Would be nice to get a shot of Neptune while it’s vortex is out.
Darn good idea. Checking capabilities: the JWST can’t observe planets Saturn or closer because they’re too bright in IR. Can observe Neptune, and Pluto, Kuyper belt objects, comets and asteroids.
Ah well.
> “This larger light collecting area means that Webb can peer farther back into time than Hubble is capable of doing”
Ya. I’m sure this was foremost in the designers of the JWST when they decided to make it an IR telescope instead of a UVIS telescope. But when it really comes down to it, why? Hubble is known to be already able to peer back in time to the time when the first galaxies formed, going to times earlier than that you’re not going to see much in IR.
> Course there is always Sag A.
Good one. Some IR frequencies (eg 2 micron) can peer through dust clouds that block visible light.
My first thought if I ruled the JWST would be to:
1) Look at the hundred nearest large galaxies to photograph stars before they go supernova. Other results from the same work would be more Cepheid variables (and other objects) for better constructing the distance ladder of the universe. It would also help in building the H-R diagram (because all stars in a galaxy are about the same distance away). And in finding strange objects.
2) Look at objects that vary rapidly with time, in particular planetary nebulae, compact supernova remnants, dusty environments around variable stars, light echoes, protoplanetary disks, direct imaging of exoplanets, and the erosion of dust clouds by the pressure of light. Catch stars in the process of formation.
3) Brown dwarf stars (including free planets) in our local space found be the WISE satellite.
The JWST would be unable to do any large scale surveys (like the SDSS, LSST, PanSTARRS etc.) and wouldn’t have a much higher resolution (if at all) than the VLT at Paranal in Chile. It will be the intermediate field of view angular scales at which it will excel.
In specifications alone, the JWST doesn’t stand out much when compared with other telescopes. Compare:
Hubble (HST)
Wavelengths 0.1 to 2.5 micrometre
Resolution 0.1 arcsec
FOV 11.3 square arcmin
Very Large Telescope (VLT)
Wavelengths 0.3 to 20 micrometre
Resolution 0.001 arcsec (for single dish 0.05 arcsec)
FOV 27 square arcmin
Webb (JWST)
Wavelengths 0.6 to 28 micrometre
Resolution 0.1 arcsec
FOV 9.7 square arcmin
Spitzer (SST)
Wavelengths 3.6 to 150 micrometre (prior to loss of coolant)
Resolution 1 arcsec
FOV 200 square arcmin
So comparing these:
Best resolution = VLT
Best FOV = Spitzer
Shortest wavelength in range = Hubble
Longest wavelength in range = Spitzer (prior to loss of coolant)
The Webb, JWST doesn’t come out on top by any of the four criteria.
Luckily, technical specifications aren’t everything.