Palomar 48-inch Observing Information

P48 Observation Planning

• Estimate total hours needed:
  • The preferred exposure time for all exposures is 60 seconds. This is generally a good compromise between background level, saturation, sampling interval, and readout and slew times.
  • For 60 second exposures, the S/N for point sources is (roughly) 300, 70, 15, and 6 for magnitudes 15, 17, 19, and 21, respectively, in both R and g' bands, under good observing conditions.
  • Note that sources brighter than 14th magnitude may saturate in a 60 second exposure.
  • The mode of the PSF distribution is approximately 2 arcseconds FWHM.
  • If applicable, break down hours by month within the semester.
• Frequency of observations:
  • If applicable, specify the cadence of exposures, i.e. the number of exposures per night, the time separations within a given night, and the number of nights between exposure sequences.
• Limits on proximity of the Moon and lunar phase.
  • Specify either dark, gray, or bright time or limits on the fraction of lunar illumination.
  • Specify minimum distance from the Moon in degrees (default is 30 degrees).
• List target position(s):
  • Targets can be given as (J2000) Right Ascension and Declination positions, and may include a spatial dimension (e.g radius). The best telescope position(s) will be selected to cover the target and avoid CCD gaps and the inactive CCD.
  • Targets can also be specified by PTF Field ID number. These IDs are preferred since this will tend to allow comparison with previous observations of the PTF survey. A table of standard PTF field IDs with RA and Dec centers is given here: PTF_Fields . A table of all PTF fields is here: PTF_Fields_all .
  • Note that the field dimensions are approximately 3.4 degrees East-West and 2.3 degrees North-South. There are ~40 arcsecond gaps between the detectors and the CCD immediately north-east of the field center is inactive.