The following functions can be used anywhere that you can write an algebraic expression in TOPCAT. They will typically be used for defining new synthetic columns or algebraically-defined row subsets. More complete documentation of them is available from within TOPCAT in the Available Functions Window.
yyyy-mm-ddThh:mm:ss.s
, where the T
is a literal character (a space character may be used instead).
Based on UTC.
Therefore midday on the 25th of October 2004 is
2004-10-25T12:00:00
in ISO 8601 format,
53303.5 as an MJD value,
2004.81588 as a Julian Epoch and
2004.81726 as a Besselian Epoch.
Currently this implementation cannot be relied upon to better than a millisecond.
isoDate
argument is
yyyy-mm-ddThh:mm:ss.s
, though some deviations
from this form are permitted:
T
' which separates date from time
can be replaced by a spaceZ
' (which indicates UTC) may be appended
to the time1994-12-21T14:18:23.2
",
"1968-01-14
", and
"2112-05-25 16:45Z
".
yyyy-mm-ddThh:mm:ss
.
yyyy-mm-dd
.
hh:mm:ss
.
java.text.SimpleDateFormat
class.
The default output corresponds to the string
"yyyy-MM-dd'T'HH:mm:ss
"
s1+s2
, but blank values can sometimes appear as
the string "null
" if you do it like that.
s1+s2+s3
, but blank values can sometimes appear as
the string "null
" if you do it like that.
s1+s2+s3+s4
,
but blank values can sometimes appear as
the string "null
" if you do it like that.
s1==s2
,
which can (for technical reasons) return false even if the
strings are the same.
startIndex
and continues to the character at index endIndex-1
Thus the length of the substring is endIndex-startIndex
.
x
,y
)
to polar (r
,theta
).
This method computes the phase
theta
by computing an arc tangent
of y/x
in the range of -pi to pi.
format
string is as defined by Java's
java.text.DecimalFormat
class.
JOHNSON_AB_V
.
JOHNSON_AB_B
.
JOHNSON_AB_Bj
.
JOHNSON_AB_R
.
JOHNSON_AB_I
.
JOHNSON_AB_g
.
JOHNSON_AB_r
.
JOHNSON_AB_i
.
JOHNSON_AB_Rc
.
JOHNSON_AB_Ic
.
JOHNSON_AB_uPrime
=u'AB.
JOHNSON_AB_gPrime
=g'AB.
JOHNSON_AB_rPrime
=r'AB.
JOHNSON_AB_iPrime
=i'AB.
JOHNSON_AB_zPrime
=z'AB.
F/Jy=10(23-(AB+48.6)/2.5)
AB=2.5*(23-log10(F/Jy))-48.6
dm[s]
, or some others.
Additional spaces and leading +/- are permitted.
hm[s]
, or some others.
Additional spaces and leading +/- are permitted.
In conversions of this type, one has to be careful to get the
sign right in converting angles which are between 0 and -1 degrees.
This routine uses the sign bit of the deg
argument,
taking care to distinguish between +0 and -0 (their internal
representations are different for floating point values).
It is illegal for the min
or sec
arguments
to be negative.
In conversions of this type, one has to be careful to get the
sign right in converting angles which are between 0 and -1 hours.
This routine uses the sign bit of the hour
argument,
taking care to distinguish between +0 and -0 (their internal
representations are different for floating point values).
bepoch
parameter is the epoch at which the position in
the FK4 frame was determined.
bepoch
parameter is the epoch at which the position in
the FK4 frame was determined.
float
(32-bit floating point value),
so this is only suitable for relatively low-precision values.
It's intended for truncating the number of apparent significant
figures represented by a value which you know has been obtained
by combining other values of limited precision.
For more control, see the functions in the Formats
class.