JDEM Mission Calculator

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Primary Mission Input Parameters:

Enter the telescope diameter: m; (max 2.5, min 0.5)
Enter the number of detectors: (max 80, min 4)
Technology (used throughput calculation):

Primary Science Input Parameters:

Weak Lensing: Enter the minimum detectable galaxy MDF: in Magnitudes AB, and Ellipticity Error .
Weak Lensing: Enter the central wavelength: microns (max 2.0, min 0.7).
BAO: Enter the minimum redshift: , and the maximum redshift: (max 2.5, min 0.7).
BAO: Enter the line flux erg/cm²·s, and the required Signal-to-Noise (sum all coadds): .
Supernova: Enter the maximum redshift ; peak spectroscopy signal/noise ratio/pixel , and R_pixel= .
Supernova: Enter coarse spectroscopy signal/noise ratio/pixel at peak (6@1.7µm, 4@2.0µm) , and R_pixel= .

Science Summary:
BAO: Millions of emission-line galaxies = , and takes years, effective volume/yr = Gpc3/yr .
SNe: Supernova in one year =
WL: Millions of resolved galaxies = in one filter band , and takes years.

Summary Table of Results:

Secondary Input Parameters:

Weak Lensing Science Input Parameters
sampling (2=ideal)
Number of Dithers
Calculate focal ratio , or use this fixed value...
Filter Bandpass, % of Central Wavelength
Target Survey Area (for zodi calc)
BAO Science Input Parameters
Max Galaxy Size Half-Light Radius, arcsec
Fixed pixel scale in arcsec/pixel
Number of roll directions
Spectroscopic success rate (0 to 1.0)
nP at k=0.2
Optimal extraction aperture radius in arcsec
Optimal extraction (w/ small pix, good snr, image)
Target Suvery Area (for zodi calc)
Supernova Science Input Parameters
Slit Width arcsec
# Lightcurve points in lab-frame
Spectrograph throughput

For the largest diameter calculated:

Calculated Observatory Properties
f/# BAO
f/# WL
diffraction l/D, arcsec
Overall System Throughput
Calculated Telescope Properties
BAO FOV, deg2
WL FOV, deg2
WL plate scale, µm/arcsec
WL pixel scale, arcsec/pixel
ee50, arcsec FWHM
PSF, arcsec FWHM


Calculated Weak Lensing Galaxy Properties
Signal, e/sec
Zodi Noise, e/sec/pixel
Excess Noise Factor (Tobs/Tideal)
Number of pixels
ABmag at MDF
Filter Tobs at max z (adjust to meet S/N), sec
Signal to Noise Ratio that meets Ellipticity error
Weak Lensing Galaxy Survey Results
WL SurveyRate, live, deg2/yr (single band)
MDF cut yield per sq arcmin
Galaxy survey rate, million gals/year
Size cut, arcsec = x EE50
Size cut yield per arcmin²
Useful/Detected Ratio
Resolved Galaxies, million gals/year


Calculated BAO Science Properties
MDLF, ph/m²·s·µm
Signal e/sec
ZodiRate, e/sec/pixel
Excess Noise Factor, (Tobs/Tideal)
Number of pixels
Tobs (adjusted to meet S/N), sec
BAO Galaxy Properties
BAO SurveyRate, live, deg2/yr
50% EE radius [asec] w/ galaxy
Min Wavelength
Max Wavelength
Comoving Volume Surveyed Gpc3/yr
Comoving Volume Surveyed Gpc3


Calculated Supernova Peak Spectroscopy Properties
Peak Spectroscopy Survey Signal (max z), e/sec
Peak Spectroscopy Zodi Noise/pixel, e/sec
ABmag at maximum redshift
Spectro Tobs at max z (adjusted to meet S/N), sec
Calculated Supernova Coarse Spectroscopy Properties
Peak Coarse Spectroscopy Signal (max z), e/sec
Peak Coarse Spectroscopy Zodi Noise/pixel, e/sec
Number of pixels
Sum light-curve Tobs at max z, sec

Supernova Exposure Times:

Telescope/Instrument Inputs
Telescope Throughput (6 reflections & mask only)
Filter or Prism Efficiency
Wave Front Error (nm, RMS)
Linear Telescope Obscuration (in %)
Observatory Input Parameters
Min. Exposure Time
New Field Acquisition Time (sec)
Max. Daily Downlink Interval (hrs)
Attitude Pointing Jitter (mas, RMS)


HgCdTe Sensor Properties
pixel size, µm
Quantum Efficiency
Read Noise (e/s)
Dark Current (e/s)
Include Pixel Size in PSF Calculation?

CCD Sensor Properties

pixel size, µm
Quantum Efficiency
Read Noise
Dark Current (e/s)
Include Pixel Size in PSF Calculation?



Costing Estimating Constraints
Trade detectors & diameter over equivalent cost
Cost/HgCdTe ($M)
Cost/CCD ($M)
Cost/0.1m diameter ($M)
Number of instruments
Diameter intercept, no detectors (m)
Merit Conversions
# yrs.
FoM per Gpc^3 at CV limit
FoM per SNe (scaled by redshift)
FoM per resolved Million WL Galaxies


version 20. MEL 03/2010