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:
- 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.
For questions on planning P48 observations, contact:
Caltech Optical Observatories (Caltech)
1200 E California Blvd.
Pasadena, CA. 91125
tb [at] astro.caltech.edu
Last modified: 15 August 2012