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Exposure Times

Due to its very high spectral resolution exposure times with Phoenix can be very long. In the JHK windows spectroscopic exposure times of 10,000 seconds on a tenth magnitude star would be needed to saturate the array. Since we are currently unable to abort an exposure in progress, we typically limit the exposure time to 900s.


In the thermal infrared (LL'M) saturation times on the sky and telescope background are 300 seconds near 3µm and 30 seconds near 5µm and limit the individual exposure times.


The minimum permissible exposure time is 1 second, so in principle spectra of zeroth magnitude stars can be obtained in the JHK bands without saturating the array. However, observations of such bright stars are not recommended because the acquisition imaging of such stars will badly saturate the array.