m67 8:50:47.81 11:50:53.0 Pa=0
The LRIS guider imaging zero point is presented below. The Guider is equipped with a BVRI filter set. Known BVI-band standards in the m67 open cluster were used to calibrate the zero point. The ZP is defined to be the magnitude of a 1 ADU detection in 1 second of integration.
The photometry used for calibration comes from Montgomery et al. 1993 AJ 106 181. In the table below, the stars used in the measurements are listed along with the Flux measured in the 1, 3 and/or 10s images. The guider image was acquired using a gain setting of 0 => gain= 0.7 e-/ADU. The LRIS guider image used was centered at: 8:50:47.81 11:50:53.0 and had a pa of 0. A finder chart of the field is shown below.
The average zero points for the stars below are: B=27.9, I=27.6 mag. The observations were originally made at an airmass of 1.045 and a correction for airmass was not made. V-band was also measured, but the data was confused by the open position.
The sensitivity for the guider for a 1 second exposure was calculated. For this calculation, the objects are assumed to be measured in a 1 arcsec aperture, with the sky bg measured in an additional 1 arcsec aperture. The pixel scale was assumed to be 0.164 arcsec/pix for this calculation. For a S/N=10, the guider would detect a B=20.1 and I=19.3 mag object in 1 second.
#photometric measurements for offset guider #airmass was 1.0469 for an average lrisoffset_120516_221.fits: FILTER2 = V lrisoffset_120530_482.fits: FILTER2 = V lrisoffset_120602_859.fits: FILTER2 = V lrisoffset_120621_248.fits: FILTER2 = R lrisoffset_120639_648.fits: FILTER2 = R lrisoffset_120705_977.fits: FILTER2 = R lrisoffset_120720_302.fits: FILTER2 = I lrisoffset_120736_629.fits: FILTER2 = I lrisoffset_120749_793.fits: FILTER2 = I lrisoffset_120805_413.fits: FILTER2 = B lrisoffset_120817_668.fits: FILTER2 = B lrisoffset_120835_916.fits: FILTER2 = B # stars in the field JANES magnitudes Measured flux ID RA(1950) DEC(1950) ID Vmag B-V V-I V-1s R-1s I-1s I-3s B-1s B-10s 1 08:48:02.170 +12:03:31.50 5179 15.009 0.799 - 259281 238158 - 109878 483319 2 08:48:01.670 +12:03:17.10 5174 14.426 1.029 - 460285 - - - 729300 3 08:48:04.531 +12:02:51.70 5209 19.908 1.499 1.437 20914 - - 16029 - - 4 08:48:05.410 +12:02:32.30 5223 16.436 1.211 1.381 482707 72400 108927 349534 19293 98771 5 08:48:02.850 +12:02:19.00 5185 18.424 0.612 0.869 225220 51495 49439 106606 - - 6 08:48:07.000 +12:03:12.40 5235 18.330 1.430 1.718 79524 12941 22030 71430 - - 7 08:48:08.150 +12:03:06.90 5253 19.685 0.707 0.976 15806 - - 10284 - - 8 08:47:59.580 +12:01:45.00 5154 19.229 1.373 1.344 85406 - 16279 62444 - - 9 08:48:03.850 +12:00:57.10 5200 14.535 0.491 - 440754 337858 - 159669 - 10 08:48:03.400 +12:00:36.70 5197 19.662 1.469 1.409 18914 - 6414 16212 - - 11 08:48:07.090 +12:01:25.20 5234 18.409 1.443 1.933 92610 11375 29865 94298 - 12936 12 08:48:08.040 +12:01:39.60 5247 18.564 1.570 2.759 131349 11158 58903 187819 - 11550 13 08:48:11.010 +12:01:32.70 5288 19.026 1.003 1.188 30727 - 5384 19484 - 14350 sky= ~610/pix 540 563 675 518 612
m67 8:50:47.81 11:50:53.0 Pa=0
Original data from 23 January 2010