The GBT pointing catalog was developed by J. J. Condon and Q. F. Yin.
The most recent catalog is PCALS4.1 which supersedes all other
pointing catalogs (as of 11 Feb 2008, see MR2C807).
Observing procedures such as AutoPeak will currently search the PCALS4.1
catalog for pointing sources. Nonetheless, the user can still use the
other catalogs by using the procedures Peak and Focus and
either input the Location directly or include the Catalog in their
scheduling blocks (see Source Catalogs).
- Note: PCALD4.1 and associated files are located in /home/astro-util/astridcats
- Note: PCALS3.3 and associated files are located in /home/astro-util/pointing/pcals3.3
- Note: PCALS4.0 and associated files are located in /home/astro-util/pointing/pcals4.0
- NVSS2.2: This original pointing catalog was based on the 1.4
GHz NVSS and contains 3399 unresolved and unconfused sources
stronger than 0.5 Jy at 1.4 GHz with two-dimensional rms position
errors of approximately 0.7 arcsec (see Condon and Yin 2000, PASP, 113, 362).
- PCALS3.3:
This was an improved pointing catalog that included additional data
from many high resolution observations now in the public domain and
contains 6857 sources. The positions have two-dimensional rms
uncertainties of 0.2 arcsec and the catalog contains moderately
accurate high-frequency flux densities. See
PTCSPN 36.1 for details.
- PCALS4.0:
This pointing includes
additional sources located primarily in the southern hemishpere sky
with a total of 7108 sources. See
PTCSPN 36.2 for details.
- PCALS4.1:
This catalog is explained in Project Note 58.
It includes an extra column called "gold"
which if it contains "P" means it is a gold standard calibrator,
and suitable for high frequency pointing.
(it does not mean that the flux density is known accurately !)
You can tell AutoPeak to choose only gold standard sources
if you include "gold=True" in the argument list for
AutoPeak or AutoPeakFocus.
There are two fortran programs that allow the user to search the
database from any linux machine. Each program prompts the user for an
observing frequency, a search radius, a flux density limit, and a
nominal position. These programs are located in the directories:
- /home/astro-util/pointing/pcals3.3 for PCALS3.3
- /home/astro-util/pointing/pcals4.0 for PCALS4.0
- /home/astro-util/astridcats/ver4.1 for PCALS4.1.
It is best to cd to the specified directory first and then run the program.
calfind: This program will return a list of
the sources meeting the specified criteria along with the source
position, the minimum and maximum beam sizes that should be used, the
observed flux densities, and the offset position. For example,
ninkasi[112]% calfind
CALFIND: Find suitable GBT pointing calibrators north of -40 deg declination
Enter the observing frequency (GHz)
22
Enter the calibration-source search radius (deg)
10
Enter the minimum calibration-source flux density (Jy) or zero for no flux limit
0.5
Enter the J2000 search center in the columns below:
HH MM SS.SS -DD MM SS.S
17 45 43.6 -28 52 15.0
---------------------------------------------------------------------------------------------
CALFIND: The GBT FWHM beamwidth is 33.6 arcsec at 22.00 GHz ( 1.4 cm wavelength)
CALFIND: GBT 22.00 GHz pointing calibrators stronger than 0.50 Jy
and lying within 10.0 deg of J2000 RA 17 45 43.60, DEC -28 52 15.0:
---------------------------------------------------------------------------------------------
IAU NAME RA (J2000) DEC MIN MAX S20 S6 S3.5 S2 S1.3 S0.7 Offset
HHMM+DDMM HH MM SS.SSSS DDD MM SS.SSS (arcsec) Jy Jy Jy Jy Jy Jy deg
---------------------------------------------------------------------------------------------
1713-2658 17:13:31.2756 -26:58:52.523 0 360 1.13 1.02 1.59 0. 0. 0.80 7.4
1717-3342 17:17:36.0300 -33:42:08.764 0 90 0.62 0.86 0. 0. 0. 1.18 7.7
1733-3722 17:33:15.1930 -37:22:32.395 0 180 0.65 0.88 0. 0. 0. 0.77 8.9
1744-3116 17:44:23.5826 -31:16:35.986 0 45 0.42 0.42 0.58 0.59 0. 0.67 2.4
---------------------------------------------------------------------------------------------
calfind2: This program is very similar to calfind
except that only one flux density is returned. The flux density is
based on an interpolated or extrapolated flux density at the specified
input frequency. For example,
ninkasi[113]% calfind2
CALFIND: I find suitable GBT pointing calibrators north of -40 deg dec.
Enter the observing frequency (GHz)
22
Enter the calibration-source search radius (deg)
10
Enter the minimum calibrator flux density (Jy) or zero for no flux limit
0.5
Enter the J2000 search center in the columns below:
HH MM SS.SS -DD MM SS.S
17 45 43.6 -28 52 15.0
--------------------------------------------------------
CALFIND: GBT pointing calibrators stronger than 0.50 Jy
at 22.00 GHz (GBT FWHM beam = 33.6 arcsec)
and lying within 10.0 deg of
J2000 RA = 17 45 43.60, DEC = -28 52 15.0
--------------------------------------------------------
IAU NAME RA (J2000) DEC S(22.0 GHz) Offset
HHMM+DDMM HH MM SS.SSSS DDD MM SS.SSS Jy deg
--------------------------------------------------------
1713-2658 17:13:31.2756 -26:58:52.523 1.06 7.4
1717-3342 17:17:36.0300 -33:42:08.764 1.07 7.7
1733-3722 17:33:15.1930 -37:22:32.395 0.80 8.9
1744-3116 17:44:23.5826 -31:16:35.986 0.62 2.4
--------------------------------------------------------
CLEO Scheduler Input Files
The program calfind2 has been used to generate pointing files that
pertain to each GBT receiver band frequency. These files can be used
as input for the CLEO scheduler program. To start the scheduler
program at the linux prompt type: "cleo scheduler".
- PCALS3.3: Files located in /home/astro-util/pointing/pcals3.3.
These ascii formated files can be input into the CLEO scheduler program.
pf.dat - 0.6 GHz
lband.dat - 1.4 GHz
sband.dat - 2.0 GHz
cband.dat - 5.0 GHz
xband.dat - 9.0 GHz
kuband.dat - 14.0 GHz
kband.dat - 20.0 GHz
kaband.dat - 32.0 GHz
qband.dat - 43.1 GHz
- PCALS4.0: Files located in /home/astro-util/pointing/pcals4.0.
These ascii formatted files are in the Astrid catalog format and
can now be input into the CLEO scheduler program.
pf.cat - 0.6 GHz
lband.cat - 1.4 GHz
sband.cat - 2.0 GHz
cband.cat - 5.0 GHz
xband.cat - 9.0 GHz
kuband.cat - 14.0 GHz
kband.cat - 20.0 GHz
kaband.cat - 32.0 GHz
qband.cat - 43.1 GHz
pointing.cat - all sources
-- DanaBalser - 23 Aug 2004
PCALS3.3