P48 Observers Information
As of this writing the only P48 instrument is the facility/
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 Halpha passbands (the g' and R passbands
along with CCD QE are depicted at right -- 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).
P48 Observation Planning
- Estimate total hours needed:
Frequency of observations:
- 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.
Limits on proximity of the Moon and lunar phase.
- 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.
List target position(s):
- 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).
- 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
table of 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.
Mosaic Camera Filter Transmission & Quantum Efficiency
(from Law et al 2009
Authorized users with questions about P48 observing should contact
p48support [at] astro.caltech.edu.