LRIS r831_8200 Throughput Measurements

Summary

Date Standard RA (J2000) DEC (J2000) Grating Block Cent. Wave Slit Airmass Conditions Figures Tables
08JUN2009 HZ_44 13:23:35.40 +36:08:00.0 831/8200 560 9000 10.00 1.01 Clear,<1" ZP_pix ZP_Ang Efficiency ZP_pix ZP_Ang Efficiency

23JAN2010 HZ_44 13:23:35.40 +36:08:00.0 831/8200 560 8000 10.00 1.00 Clear,<1" ZP_pix ZP_Ang Efficiency ZP_pix ZP_Ang Efficiency

23JAN2010 HZ_44 13:23:35.40 +36:08:00.0 831/8200 560 10001 10.00 1.00 Clear,<1" ZP_pix ZP_Ang Efficiency ZP_pix ZP_Ang Efficiency

03NOV2010 G191B2B 05:05:30.62 +52:49:54.0 831/8200 680 10500 1.00 1.17 Clear,<1" ZP_pix ZP_Ang Efficiency ZP_pix ZP_Ang Efficiency

16DEC2010 G191B2B 05:05:30.60 +52:49:54.0 831/8200 560 8001 10.00 1.05 Clear,<1",direct ZP_pix ZP_Ang Efficiency ZP_pix ZP_Ang Efficiency

16DEC2010 G191B2B 05:05:30.60 +52:49:54.0 831/8200 560 9999 10.00 1.05 Clear,<1",direct ZP_pix ZP_Ang Efficiency ZP_pix ZP_Ang Efficiency

16DEC2010 Feige110 23:19:58.23 -05:09:59.2 831/8200 560 8001 1.00 1.55 Clear,<1" ZP_pix ZP_Ang Efficiency ZP_pix ZP_Ang Efficiency

16DEC2010 Feige110 23:19:58.40 -05:09:56.0 831/8200 560 8001 10.00 1.52 Clear,<1",direct 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.

Date	Standard	RA (J2000)	DEC (J2000)	Grating	Block	Cent. Wave	Slit	Airmass	Conditions	Figures	Tables
08JUN2009	HZ_44	13:23:35.40	+36:08:00.0	831/8200	560	9000	10.00	1.01	Clear,<1"	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
23JAN2010	HZ_44	13:23:35.40	+36:08:00.0	831/8200	560	8000	10.00	1.00	Clear,<1"	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
23JAN2010	HZ_44	13:23:35.40	+36:08:00.0	831/8200	560	10001	10.00	1.00	Clear,<1"	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
03NOV2010	G191B2B	05:05:30.62	+52:49:54.0	831/8200	680	10500	1.00	1.17	Clear,<1"	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
16DEC2010	G191B2B	05:05:30.60	+52:49:54.0	831/8200	560	8001	10.00	1.05	Clear,<1",direct	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
16DEC2010	G191B2B	05:05:30.60	+52:49:54.0	831/8200	560	9999	10.00	1.05	Clear,<1",direct	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
16DEC2010	Feige110	23:19:58.23	-05:09:59.2	831/8200	560	8001	1.00	1.55	Clear,<1"	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency
16DEC2010	Feige110	23:19:58.40	-05:09:56.0	831/8200	560	8001	10.00	1.52	Clear,<1",direct	ZP_pix ZP_Ang Efficiency	ZP_pix ZP_Ang Efficiency

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.

Last modified: Sun Feb 6 23:02:02 2011