WISH: Wide-field Imaging Surveyor for High-redshift


Proposed Specifications


Primary Mirror Diameter1.5m
Field of View∼850 arcmin2
Focal Plane Temperature80K, Passive Cooling
Wide-Field Near-IR Camera
DetectorHgCdTe (18μm/pixel is assumed)
Operation Temperature40K, Passive Cooling
Observing ModesBroad-band and Narrow-band imaging. Optional spectroscopy mode (see below)
Filters6 broad-band filters covering 1μm to 4.5μm,
Narrow-band filters or slitless spectroscopy (TBD)
Spacecraft / Launcher
OrbitSE-L2 (TBD)
RocketHII-A (TBD)
Total Weight1.3t (matched to HII-A dual launch)
Mission Lifetime∼5 years

Broad-band Filters


Specifications of broad-band filters proposed in the mission proposal.

NameλcenterFWHMw0w1RDiff. LimitRef. NameFile
[μm] [μm] [μm] [μm][arcsec]
Filter 01.0400.2800.9001.1803.7140.174WBF0300_00wbf0300_00.txt
Filter 11.3600.3601.1801.5403.7780.228WBF0300_01wbf0300_01.txt
Filter 21.7750.4701.5402.0103.7770.298WBF0300_02wbf0300_02.txt
Filter 32.3200.6202.0102.6303.7420.389WBF0300_03wbf0300_03.txt
Filter 43.0300.8002.6303.4303.7880.508WBF0300_04wbf0300_04.txt
Filter 53.9651.0703.4304.5003.7060.665WBF0300_05wbf0300_05.txt


Exposure Time Calculator

Optional Spectroscopy Modes

We have been studying possibilities of adding spectroscopic capabilities. There are couples of possibilities:

  1. Wide-field slitless spectroscopy using grism and Wide-Field Near-IR Camera. We have obtained a design with spectral resolution ∼100, wavelength 0.9μm - 2.5μm with good image quality. A grism for longer wavelength could be also possible.
  2. The central optical path from the secondary mirror is not used by the Wide-Field Near-IR Camera. We may be able to use this central part for a separate spectroscopy unit.

For the second option, there are two proposals.