P48 Observer Information
Samuel Oschin/P48 Telescope exterior. (Palomar/Caltech)
The Palomar 48-inch Samuel Oschin Telescope
(P48) operates exclusively in a robotic, queue-scheduled service-observing mode.
Allocation of P48 observing time is handled through the
Intermediate Palomar Transient Factory Consortium
(iPTF) for iPTF observers, and the
time allocation process for Caltech astronomers.
Caltech observers can find P48 proposal information at the
As of this writing the only P48 instrument is the facility/iPTF Mosaic wide-field camera
(the former CFHT-12K
camera). The P48 Mosaic camera has a 12-CCD mosaic focal plane (depicted at right—taken from
Law et al 2009).
The active focal plane covers a 7.25 deg2 field of view with a pixel size of 1 arcsec.
The camera supports filters in SDSS g', R-Mould, and Hα passbands (the g' and R passbands
along with CCD QE are depicted below—from
Law et al 2009).
Detailed information on the P48 Mosaic camera in its refurbished state can be found in
Ramher et al 2008
(and this local copy).
- 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):
Mosaic Camera filter transmission and quantum efficiency.
(Law et al 2009)
- 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.
Please see the
standard PTF field IDs with RA and Dec centers.
- 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.