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Hubble Space Telescope
WFPC2 ETC for Extended Sources + Background - v4.0

For help, select the colored text. General info. and help.


Stellar Spectra:

Surf. Brightness: (mag. arcsec-2)

Spectral Type:


Power Law:

Flux: (erg cm-2 s-1 Hz-1 arcsec-2)

Freq./Wave.: (Hz/Ang.) Sp. Index:


Emission Line:

Line Flux: (erg cm-2 s-1 arcsec-2)

Line: : (units)

Background Stellar Light:

Surface Brightness: (mag. arcsec-2)

Spectral Type:

Reddening (color excess): E(B-V):

Sky Background:

Rough estimate: Low Average High


Detailed estimate based on object location:

Right Ascension: H M S
(Equinox 2000)

Declination: D ' ''
(e.g. "23 55 31.1" or "-00 05 34.3", omit + signs)

Sun Angle: D (usually 90 degrees) Low Sky?


User specified V magnitude for sky:  mag arcsec-2

Instrument Configuration:

Configuration: WFC PC

A/D gain: 7 e-/ DN 14 e-/ DN


If using LRF filter give desired Central Wavelength:  Ang.

Exposure: Enter either S/N or Exposure Time.

Signal to Noise (per pixel):

Exposure Time: Sec.