Coordinates and magnitudes

We need to observe near-IR spectrophotometric standards, as we can calculate their synthetic photometry in the medium-band system. The standards are taken from the lists at STScI - this README has lots of background information. We should observe multiple stars, as the spectro-photometry for individual stars has uncertainties of ~0.05. Hopefully these uncertainties are at least somewhat uncorrelated from one star to the next. The following 10 stars have the "right" combination of coordinates, reliable spectra, and magnitudes:

ID Name RA DEC J1 J2 J3 H1 H2 Ks Max. t

[1] G191B2B 05:05:30.6 +52:49:53.6 12.44 12.52 12.54 12.62 12.67 12.75 4 sec

[2] GD71 05:52:27.5 +15:53:16.6 13.66 13.72 13.75 13.82 13.87 13.95 7 sec

[3] GD153 12:57:02.4 +22:01:56.0 13.99 14.06 14.09 14.16 14.21 14.29 8 sec

[4] P041C 14:51:57.9 +71:43:13.0 11.08 10.94 10.85 10.60 10.57 10.55 1 sec

[5] P177D 15:59:13.6 +47:36:40.0 12.49 12.33 12.22 11.96 11.92 11.90 2 sec

[6] P330E 16:31:33.6 +30:08:48.0 12.02 11.86 11.76 11.49 11.45 11.42 1 sec

[7] 1740346 17:40:34.7 +65:27:15.0 12.18 12.12 12.09 12.02 12.02 11.99 2 sec

[8] 1805292 18:05:29.3 +64:27:52.1 12.10 12.07 12.06 12.02 12.02 12.00 2 sec

[9] 1812095 18:12:09.6 +63:29:42.3 11.43 11.39 11.37 11.31 11.30 11.28 1 sec

[10] KF06T1 17:57:58.5 +66:52:29.3 11.89 11.84 11.61 11.31 11.30 -- 1 sec

ID	Name	RA	DEC	J1	J2	J3	H1	H2	Ks	Max. t
[1]	G191B2B	05:05:30.6	+52:49:53.6	12.44	12.52	12.54	12.62	12.67	12.75	4 sec
[2]	GD71	05:52:27.5	+15:53:16.6	13.66	13.72	13.75	13.82	13.87	13.95	7 sec
[3]	GD153	12:57:02.4	+22:01:56.0	13.99	14.06	14.09	14.16	14.21	14.29	8 sec
[4]	P041C	14:51:57.9	+71:43:13.0	11.08	10.94	10.85	10.60	10.57	10.55	1 sec
[5]	P177D	15:59:13.6	+47:36:40.0	12.49	12.33	12.22	11.96	11.92	11.90	2 sec
[6]	P330E	16:31:33.6	+30:08:48.0	12.02	11.86	11.76	11.49	11.45	11.42	1 sec
[7]	1740346	17:40:34.7	+65:27:15.0	12.18	12.12	12.09	12.02	12.02	11.99	2 sec
[8]	1805292	18:05:29.3	+64:27:52.1	12.10	12.07	12.06	12.02	12.02	12.00	2 sec
[9]	1812095	18:12:09.6	+63:29:42.3	11.43	11.39	11.37	11.31	11.30	11.28	1 sec
[10]	KF06T1	17:57:58.5	+66:52:29.3	11.89	11.84	11.61	11.31	11.30	--	1 sec

The coordinates are for the stars themselves; to get them on the array in the NorthEast quadrant, offset the telescope by 7' South and 7' West after acquiring the star. Finding charts (both 30'x30' and 10'x10') can be found in this directory.

Magnitudes are synthetic, Vega; AB offsets can be found under Instrument: Filter info. Their uncertainties are about ~0.05 mag. The final column lists the maximum exposure time to stay below 1% non-linearity for a FWHM of 0.9''. This is not a hard limit, as we expect to be able to correct for non-linearity fairly well, but it gives an indication of exposure times. A 5-point dither pattern with these exposure times should work in all filters.

Calibration of array - array sensitivity

The standard location for the standard stars is on the NE array. However, we also need to calibrate the relative sensitivity between the 4 arrays. We have reasonably good estimates for the array-array sensitivity (from flatfields, M67, and a star imaged on each of the 4 arrays), but it will be good to redo the latter test in the second run.