Output format for
Three possible output formats exist for the list of astronomical
objects generated by REFNET.
- ASCII - This is the standard human-readable form. Below is a typcial
example of how this form looks:
RA Decl. Mag. Radius Angle
hr mn sec dec mn sec Red Blue arcsec deg
00 00 02.546 -00 04 22.21 12.9e 13.0e 265.0 188.3
00 00 04.171 -00 01 57.05 17.4 18.1 132.7 208.1
00 00 04.715 -00 03 25.26 17.1 17.3 217.1 199.0
00 00 04.821 +00 03 35.52 16.4 18.0 227.3 341.5
00 00 06.007 -00 02 47.01 15.3 17.2 189.8 208.3
00 00 06.895 +00 02 29.03 17.3 18.2 181.4 325.2
00 00 07.334 -00 00 23.05 15.5 0.0m 112.4 258.2
The "Radius" column is the distance from the center of the field-of-view
to the object. The "angle" is the angle from the center of the field-of-view
to the object where the reference line is from the center to North and
the angle increases in the same sense as RA. In the 'Mag.' column, the
letters following some of the magnitudes are flags indicating the reported
magnitude is probably in error. The 'e' flag means that the value is
probably too high. The 'm' value means that the value is missing or
- IRAF - This format is suitable for generating images in
IRAF. The 'mkobjects' task will accept files in this format and,
when other parameters are properly set will generate an image similar
to one taken from a real CCD. The focal length and pixel size of
the simulated telescope must be included for this output style. A sample
file format is should below:
42.68 12.89 14.400
217.22 13.47 20.600
176.18 19.03 16.200
100.86 20.49 14.000
131.54 24.49 20.600
192.03 27.02 18.200
115.88 30.09 12.400
65.14 32.13 12.400
. . .
. . .
. . .
The number columns mean the following: column 1 is the CCD pixel number
in the x direction; column 2 is the CCD pixel number in the y direction;
column 3 is the magnitude.
- Catalog -
The catalog file is in binary data file format. Each entry is
composed of three 4-byte integers, and the byte order is the natural
order for Silicon Graphics, Sun (and others), but will require the
BIG_ENDIAN argument on IBM-PC, Digital Equipment Corp. and similar
computers. This is the same format as was used for the UJ1.0. Each
entry consists of three 4-byte integers, and the ordering is a
The integer RA is given in quanta of 1/100 arcsecond. Take the
traditional hours of RA and multiply by (15*3600*100) to obtain the
appropriate integer value. The integer SPD is given in quanta of
1/100 arcsecond. Take the traditional degrees of Dec, add 90 and
multiply by (3600*100) to obtain the appropriate integer value. The
decimal digits of the mag/flag word are:
- i*4: Integer RA
- i*4: Integer SPD
- i*4: Magnitudes and flags
- S = sign. If negative, this object correlates with a GSC object.
- Q = quality. If Q = 1 then the internal PMM flags indicate that the
magnitude(s) might be in error. If Q = 0, then things looked OK. This
is generally an indication of saturation so the listed magnitude is
probably too high.
- FFF = field on which this object was detected. In the north, we
adopted the MLP numbers for POSS-I. These start at 1 at the north pole
and end at 937 in the -30 degree zone. In the south, the fields start
at 1 at the south pole and the -35 zone ends at 408.
- BBB = blue mag. Integer in units of 1/10 magnitude. The range 0
through 250 contains reasonable magnitudes. The range 500 through 750
contains PMM flux estimators when the flux estimator was obviously
incorrect. Exception: When a GSC entry was uncorrelated in red or
blue, Q=0, FFF=0 and BBB=0. RRR is set the the GSC magnitude.
- RRR = red mag. Integer in units of 1/10 magnitude. Same comments
as in the blue but the value 999 is used when the blue correlates with
the GSC and the red was uncorrelated.
© Lowell Observatory 2008
Contacts: Ted Bowell and Bruce Koehn
Last modified: 2008 April 15