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TMT Spectroscopic ETC (under construction)

For details of the calculation, see TMT ETC Readme page.
Please direct the enquiries about TMT ETC to tetsuya.hashimoto_at_nao.ac.jp (change _at_ to @).
Basic parameters of TMT first generation instruments
(spectroscopic mode)
Wavelength coverage (μm) 0.8 – 2.4 0.31 - 1.0 0.95 - 2.45
Spectral resolution R = λ/Δλ 4000 1000-8000 3000?
Field of view 0".064x0".512 - 2".2x4".55 8'.3 x 3'.0 2' x 2'
Detector Hawaii-4RG
(4K x 4K pix)
Unreleased Hawaii-2RG
(2K x 2K pix)
Pixel scale (mas/pix) 4, 9, 25, 50 52 60
Typical FWHM of PSF (mas) 8 with AO
600 w/o AO
800 w/o AO 8 with AO
600 w/o AO
Read out noise
(electrons/pixel in rms)
2 3 15
Dark current (electrons/sec/pixel) 0.002 0.0003 0.01
Instrument throughput (%) ~34-42 with AO ~27 ~30-40 with AO

Source Geometry:
Extract square region
  = slit width x spatial length = x arcsecond2

Point Spread Function:
Seeing size: mas

Target Spectral Energy Distribution:

at μm
Equivalent Width =
Line Width km/s

E(B-V) =

(N/A, under construction)

Redshift =

Scale Flux Density by using:
Magnitude system
= mag for point source
  mag/arcsecond2 for extended source
= mag for point source
  mag/arcsecond2 for extended source
Fλ = erg/s/cm2/μm for point source
  erg/s/cm2/μm/arcsecond2 for extended source
= M/yr for point source
  M/yr/arcsecond2 for extended source

Sky Condition:
Observatory Site: (valid for ground telescope)
Lunar Phase Angle: degree
Angular distance between moon and target: degree

System Configuration:
Use instrument parameters for
Telescope Diameter: m
Spectral resolution R = λ/Δλ =
Pixel scale: mas/pixel
Pixel scale in along dispersion axis: /pixel
Detector dimension along dispersion axis: pixel
(Please don't input too large number due to limitation of machine power)
Central wavelength on detector: μm
Read out noise: electrons/pixel in rms
Dark current: electrons/sec/pixel
Total efficiency: including both optics efficiency and instrumental quantum efficiency

Exposure Time:
Total exposure time = second on source x frames