<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<!--Converted with LaTeX2HTML 98.1p1 release (March 2nd, 1998)
originally by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds
* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan
* with significant contributions from:
Jens Lippmann, Marek Rouchal, Martin Wilck and others -->
<HTML>
<HEAD>
<TITLE>Description of INVENTORY Keywords</TITLE>
<META NAME="description" CONTENT="Description of INVENTORY Keywords">
<META NAME="keywords" CONTENT="vol2">
<META NAME="resource-type" CONTENT="document">
<META NAME="distribution" CONTENT="global">
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<LINK REL="STYLESHEET" HREF="vol2.css">
<LINK REL="next" HREF="node77.html">
<LINK REL="previous" HREF="node67.html">
<LINK REL="up" HREF="node64.html">
<LINK REL="next" HREF="node77.html">
</HEAD>
<BODY >
<!--Navigation Panel-->
<A NAME="tex2html2375"
HREF="node77.html">
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
SRC="icons.gif/next_motif.gif"></A>
<A NAME="tex2html2372"
HREF="node64.html">
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
SRC="icons.gif/up_motif.gif"></A>
<A NAME="tex2html2366"
HREF="node75.html">
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
SRC="icons.gif/previous_motif.gif"></A>
<A NAME="tex2html2374"
HREF="node1.html">
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
SRC="icons.gif/contents_motif.gif"></A>
<BR>
<B> Next:</B> <A NAME="tex2html2376"
HREF="node77.html">Formats of Tables</A>
<B> Up:</B> <A NAME="tex2html2373"
HREF="node64.html">Object Search and Classification</A>
<B> Previous:</B> <A NAME="tex2html2367"
HREF="node75.html">The Classification</A>
<BR>
<BR>
<!--End of Navigation Panel-->
<H1><A NAME="SECTION00740000000000000000">
Description of INVENTORY Keywords</A>
</H1>
There are several keywords in the context keyword area which hold the values of
parameters which control the performance of <TT>INVENTORY</TT>. They are listed
here. Additional information is also supplied (separated by slashes): Keyword
type -- Integer (I) or Real (R) -- and the maximum number of
values stored by a keyword. A description is added following each keyword. <DL COMPACT><DT>ANALITER
<DD>--
Default value of this keyword is equal to 0 and corresponds to the case
that only the base version of the command <TT>ANALYSE/INV</TT> is used.
Any positive value sets the number of additional iterations. In
each of these iterations the contributions from stellar neighbours are
subtracted using the empirical one-dimensional point spread function.
<DT>BRGHTLMT/R/1
<DD>--
Divides objects into bright and faint for classification purposes.
Should be close to the magnitude corresponding to the beginning of
saturation effects.
<DT>BRIGHTOB/R/1
<DD>--
Parameter, which helps to remove spurious faint components of large
bright objects. May modify central parts of real objects. Should be
disabled by setting to zero when photometric accuracy is important.
<DT>BRGTCTRL/I/1
<DD>--
Many spurious faint objects are detected around
very bright ones when this keyword is set to 0. Increasing it helps
to eliminate spurious objects. Too large a value may result in
disapearance of some real objects.
<DT>CLASSPAR/R/3
<DD>--
Controls the selection of seed objects for classification. The
first component defines half-width of stellar objects band in a
magnitude versus relative gradient plot. The second value sets an
upper limit for relative gradient for seed galaxies. The third
component tells how much brighter in magnitudes the seed objects should
be in relation to the limiting magnitude. All three components are
used in <TT>CLASSIFY/INV</TT>. The first component is also used in
<TT>ANALYSE/INV</TT> for picking out objects similar to stars.
<DT>CTRLMODE/R/1
<DD>--
Controls the calculation of sky background with the help of the
subroutine MODE.
This subroutine returns the modal value of the pixel distribution when
CTRLMODE is set to 3.0. Repetitively clipped means it is returned when
CTRLMODE is set to 0.0, with some saving of the execution time.
<DT>CVFACTOR/R/1
<DD>--
Stops iterations in subroutine MODE, when the difference between the last
two iterations for mode is smaller than the last <IMG
WIDTH="19" HEIGHT="21" ALIGN="BOTTOM" BORDER="0"
SRC="img170.gif"
ALT="$\sigma$">
multiplied by
CFCT.
<I>Recommended value is 5.0.</I> Smaller values increase execution time
with only little improvement of accuracy. Larger values may harm the
accuracy.
<DT>DEBUG/I/1
<DD>--
us used ti invoke debuging outputs.
<DT>DFVALLEY/R/1
<DD>--
Required depth of valley between two components that is necessary
for accepting them as two separate objects.
<I>Recommended value is 0.02.</I>
<DT>DISTANCE/R/1
<DD>--
Limiting distance in a parameters space for including object in a
particular class of objects. Used in <TT>CLASSIFY/INV</TT>
<DT>ELONGLIM/R/1
<DD>--
Image elongation above which an object is checked for duplicity.
<I>Recommended value is 0.25.</I>
<DT>ETAFUNCT/R/1
<DD>--
Petrosian <IMG
WIDTH="17" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img171.gif"
ALT="$\eta$">-function used in the determination of the
Petrosian radius and Petrosian magnitude.
Berkeley astronomers are using a value of 2.0. When working with many
automatically detected faint objects this large value often fails to give
consistent results for all objects. Therefore a smaller value, such
as <I>1.5, is recommended</I>.
The value 1.39 corresponds roughly to de Vaucouleur's definition of ``half
luminosity radius''.
<DT>EXPRTIME/R/1
<DD>--
Time of exposure expressed in units referred to in keyword ZEROMAGN.
<DT>FIELDVAR/I/1
<DD>--
Concerns the character of variations of sky background. It is set
to 0 when these variations are additive. It is 0 when they are due
to sensitivity changes.
<DT>FILTER/R/1
<DD>--
Sets slevel of bright pixel filtering.
<DT>FULLPSF/I/1
<DD>--
Extend in pixels of 2-dimensional p.s.f.
<DT>HALFEDGE/I/1
<DD>--
Defines size of a subarray that is used for calculating local sky
background, and for profile analysis. It is equal to a distance,
measured in pixels, between the central pixel and an edge of a subarray.
The size of a subarray is equal to
<!-- MATH: $(1+2\times{\rm IHED})^2$ -->
<IMG
WIDTH="163" HEIGHT="48" ALIGN="MIDDLE" BORDER="0"
SRC="img172.gif"
ALT="$(1+2\times{\rm IHED})^2$">.
IHED cannot be larger than 50, so that the maximum size of a subarray is
<!-- MATH: $101\times101$ -->
<IMG
WIDTH="97" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img173.gif"
ALT="$101\times101$"> pixels. Objects of interest should be smaller than the
subarray. If the value 50 is too small, then the image should be squeezed.
Minimal value is 4.
<I>Recommended value for most of applications is between 8 and 12.</I>
<DT>IJBORDER/I/4
<DD>--
Sets limits of the investigated area.
<DT>ISOPHOTR/I/1
<DD>--
Controls use of outside values of isophotal radia. When set to 1, then
isophotal radia are read from column RAD_ISO into an input table.
It is useful when measuring colours of galaxies.
<DT>ITERATE/I/2
<DD>--
Condition for terminating iterations during classification and allowable
number of iterations.
<DT>LHCUTS/R/2
<DD>--
Low and high cuts applied for more correct treatment of
bad pixels and saturated regions.
The <I>low cut</I> should be <I>smaller than any valid data</I>.
The <I>high cut</I> should be <I>little less than the image saturation
level</I>.
It is advisable to look carefully at images of bright stars with the help
of the image display in order to set a high cut.
<DT>MARGINS/I/1
<DD>--
Width in pixels of frame margins where objects are not detected.
<DT>MULTDTCT/R/1
<DD>--
Allowed separation of pixels at multiple detections.
Individual detections separated not more than by
MULTDTCT pixels are treated
as the same detection.
<DT>NEBLIMIT/R/1
<DD>--
Used in cases when faint members of clusters of galaxies pretend to
be very large. In all other cases should be disabled by setting to zero.
<DT>NETHEDGE/I/1
<DD>--
Half edge of the regions used to determine preliminary sky background
in a net of regions.
<DT>OUPROFIL/I/1
<DD>--
Sets number of pixels spaced points of objects' profiles recorded in
output table.
<DT>PAIRSPRT/R/1
<DD>--
Allowed minimal separation of double objects expressed in pixels.
Should be <I>little larger than</I> the size of <I>the seeing disk.</I>
<DT>PRFLCLNG/R/3
<DD>--
Parameters used for profile cleaning.
<DT>PHYSICAL/I/1
<DD>--
Tells if searched area is defined by physical coordinates.
<DT>PRFLCTRL/I/1
<DD>--
Gives the number of central points of the standard Point Spread Function
to be updated by program. Input profile as given by keywords SPROFILx
and is used when PRFLCRTL is 0. N central points are updated with the help
of stars selected by program when PRFLCRTL is +<I>n</I>, and the program will
ask for selecting stars with the help of the cursor when PRFLCRTL is -<I>n</I>.
<I>Usually 5 or 6 is sufficient.</I>
May depend on frame origin, seeing and pixel size.
<DT>SGFACTOR/R/1
<DD>--
Factor used to set clipping limits in subroutine MODE.
<I>Recommended value is 2.0.</I>
<DT>SKYDETER/I/1
<DD>--
Sets accuracy of the sky background determination.
<DT>STMETRIC/R/2
<DD>--
Radii of two circular apertures used to determine aperture magnitudes.
They are expressed in pixels.
<DT>SPROFIL1/R/5 - SPROFIL5/R/5
<DD>--
Innermost 25 points of one dimensional logarithmic
differential Point Spread Function. The spacing
of entries is by one pixel. Each k-th value is equal to decimal logarithm
of k-1 value of the stellar Point Spread Function divided by its k-th
value.
<DT>TRESHOLD/R/1
<DD>--
Limiting threshold above sky background level used at object detection
and at calculating isophotal magnitudes and sizes. It is expressed
in units of sky background. Too low a value results in many spurious
detections and corresponding long execution time. It is advisable
to start with a relatively <I>large</I> value of TRESHOLD and check it on
a small part of a frame defined with the help of the EXTRACT command.
<DT>UNDRSMPL/I/1
<DD>--
Undersampling factor.
<DT>UNITS/I/1
<DD>--
Switched between background units (0) and instrumental units (1)
<DT>XYBORDER/R/2
<DD>--
Limits of investigated area in physical units.
<DT>YFACTOR/R/1
<DD>--
The ratio of ``Y'' to ``X'' dimensions of a box used at duplicity check.
<I>Recommended value is 0.6.</I>
<DT>ZEROMAGN/R/1
<DD>--
Sets a zero point of magnitudes. Its use is controlled by keyword MGNTCTRL.</DL>
<P>
<HR>
<!--Navigation Panel-->
<A NAME="tex2html2375"
HREF="node77.html">
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
SRC="icons.gif/next_motif.gif"></A>
<A NAME="tex2html2372"
HREF="node64.html">
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
SRC="icons.gif/up_motif.gif"></A>
<A NAME="tex2html2366"
HREF="node75.html">
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
SRC="icons.gif/previous_motif.gif"></A>
<A NAME="tex2html2374"
HREF="node1.html">
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
SRC="icons.gif/contents_motif.gif"></A>
<BR>
<B> Next:</B> <A NAME="tex2html2376"
HREF="node77.html">Formats of Tables</A>
<B> Up:</B> <A NAME="tex2html2373"
HREF="node64.html">Object Search and Classification</A>
<B> Previous:</B> <A NAME="tex2html2367"
HREF="node75.html">The Classification</A>
<!--End of Navigation Panel-->
<ADDRESS>
<I>Petra Nass</I>
<BR><I>1999-06-15</I>
</ADDRESS>
</BODY>
</HTML>
