LRIS r600_7500 Throughput Measurements

Summary

Date	Standard	RA (J2000)	DEC (J2000)	Grating	Block	Cent. Wave	Slit	Airmass	Conditions	Figures	Tables
30MAY2008	HZ_44	13:23:37.85	+36:08:16.2	600/7500	560	6796	1.00	1.06	Clear	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
03OCT2008	Feige110	23:19:58.59	-05:09:59.2	600/7500	560	6900	1.00	1.51	Clear,<1"	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
05OCT2008	G191B2B	05:05:30.44	+52:49:53.4	600/7500	560	6900	1.00	1.04	Clear,<1"	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency

The above table summarizes the set of standard stars that have been processed. They should have all been observed in photometric conditions. You may note, however, that the slitwidth and airmass vary consdierably. The efficiency calculations have made an estimated correction for the airmass, but NO correction for slit losses. If you have a standard star to contribute, please contact the Keck staff or JXP. Here is a summary of the standards observed:

ZP_pix: Zero point (AB magnitude) to give one electron per second per pixel. This does NOT include an airmass correction. ZP_Ang: Zero point (AB magnitude) to give one electron per second per Angstrom. This does NOT include an airmass correction. Efficiency: Total efficiency of the telescope+instrument. This does include an airmass correction.

Current ZP and Efficiency Curves

The following figures show the most recent measurements of the ZeroPoint and efficiency measurements hopefully observed through a sufficiently large slit (usually >2 arcsec).

Time Evolution

The following figure shows the time history of the total efficiency (telescopes + instrument) evaluated at a few wavelenths as a function of time. Note that this analysis is restricted to wider slits.