1/16/2024 0 Comments Flux density calculatorIn Phase 2, the image quality will still be the only applicable constraint for seeing-limited modes, In Phase 1, the seven current seeing categories are replaced by seven turbulence categories for all instruments.Įach category can be defined by other parameters than a pure seeing threshold, depending on the instrument.įor all instruments, all categories share the same statistical probability of realisation, which is key for an accurate The handling of atmospheric constraints thus changes for both Phase 1 (proposal preparation) and Phase 2 (OB preparation). Required by all instruments and modes, whether they are seeing-limited or AO-assisted. Starting from Period 105, the turbulence constraints are standardised to the turbulence conditions Time and the fraction of turbulence taking place in the atmospheric ground In order to properly schedule observations and ensure that their science goals are achieved. With the advent of instruments using new adaptive optics (AO) modes, new turbulence parameters need to be taken into account Sky Conditions Turbulence Category (T category) Note that Ω should not exceed the 14×14 pixels IFU area (0.2 arcsec/pix * 14 pix) 2 = 7.84 arcsec 2. To obtain the S/N per arcsec 2, enter Ω=1 here. The source is assumed to have a uniform intensity over the given area (Ω) on the sky, the number of pixels in the S/N area is Note that the magnitude (or the flux for an emission line) is always given per arcsec 2 for extended sources. The target object is assumed to have a uniform intensity and the S/N on the result page is given per spatial pixel on the detector. The reference area for the S/N is circular with a radius equal to FWHM of the Image Quality PSF at the airmass and wavelength of observation. This can be selected for objects with an angular radius of much less than the sky-projected pixel size. For extended sources, the magnitude must be given per square arc second.Ī point source is assumed to be an emitter with negligible angular size. You must select the filter and filter magnitude for proper scaling of the template spectrum. The reference for the zero points used in conversion into photon fluxes: NOTE! The wavelength range of the uploaded spectrum must cover the spectral range of the selected instrument mode as well as the wavelength range of the photometric band in which the magnitude is given.Įnter the V (650 nm), Y (1000 nm), J (1250 nm), H (1650 nm), or K (2160 nm) magnitude, ideallyĬlosest in wavelength to the selected filter. The absolute flux scale is not significant since the spectrum will be scaled to the given magnitude in the given band. In both cases the values in the first column should be the wavelength in nm units and ascending order the second column is the the flux density in a unit proportional to erg/cm2/s/A. ASCII: Text file with two numerical columns, separarted by any number of spaces or tabs.A FITS 2-D image in the primary HDU with NAXIS1 = 2 and NAXIS2 =, where is the number of points in the spectrum.Users can upload a file with the spectral flux distibution to the ETC server. References: Pickles (1998, PASP 110, 863) Coleman et al.: 1980ApJS Kinney at al.: 1996ApJ. The target model can be defined by a template spectrum which is scaled to the provided magnitude and filter. The intensity distribution is scaled to the object magnitude. The target model is a blackbody defined by its temperature, expressed in Kelvin. The flux density level is determined from the specified object magnitude. The flux density is constant at all wavelengths (F(λ) = const.) The following options are available to describe the input spectrum of the target.
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