|
Import Photometry Catalog
The Import Photometry Catalog dialog imports
a catalog file containing object coordinates and other data,
identifies the objects in the image or image set, and performs
photometric calibration using standard stars from the catalog. The
catalog file may have been created using an editor like
Notepad or saved from a coordinate database, a Mira
photometry report, the
Source Extraction procedure, etc. The text file
requirements are given below.
Note that the dialog initially opens with all
controls deactivated except for the Profile and [Open
Catalog] button. All other controls activate after you open
a catalog.
|
Import Photometry Catalog Properties
|
|
Profile [|>]
|
The name of the parameter profile to apply. This
selects the values of all properties except the catalog preview.
Select a saved profile from the list or use the profile menu button
to save a new profile.
|
|
Catalog Data Column Map
|
This group maps the import parameters to columns
in the catalog preview. If there is no entry for the item (e.g.,
Weight), select --none-- for the column.
|
|
Open Catalog
|
Click this button to select and open a catalog
file.
|
|
Coordinates
|
Select the type of coordinate system to import
from the catalog file. You can choose the following coordinate
systems:
Column, Row are pixel
coordinates.
HMS, DMS are Right
Ascension (RA) and Declination (Dec) expressed in Hours, Minutes,
and Seconds, and Declination expressed in Degrees, Minutes, and
Seconds. This options requires the image to have a
World Coordinate System calibration.
Deg, Deg are Right
Ascension (RA) and Declination (Dec), both expressed in units of
decimal degrees. This requires the image to have a
World Coordinate System calibration.
|
|
Import at Line
|
Select the first line of data to import from the
catalog preview. This allows you to skip over headings and any
number of data lines at the beginning of the catalog.
|
|
Import >>
|
Click this button to import the catalog and apply
it to the image.
|
|
 Confirm Import
|
Checking this box causes Mira to print a summary
of imported data in a text window following import. If right
ascension is imported from HMS coordinates, then it is listed in
degrees, which are the native units of the equatorial calibration
in the World Coordinate System.
|
|
[X]
|
Closes the dialog.
|
Procedure
-
Click [Open
Catalog] to select the catalog file using the Open
dialog. The contents of the file are listed as a grid in the
Previewsection at the bottom of the
dialog. Note that the other controls are deactivated until you open
a catalog file into the Preview.
-
In the Catalog Data Column
Map, select the column for each data item. If the items does
not exist in the catalog, select --none--.
-
Select the coordinates format from the
Coordinates list. Only (Column, row) and (RA,
Dec) formats are available. The coordinate names listed in
the Catalog Data Column Map, change
based on this selection. Note that RA and Dec values may appear in
the catalog in various formats such as right ascensions of
12h14m13.555s or 21.444532, etc. Each field may contain blanks, as
in "19 12.5566" but cannot contain a tab because tabs are only
allowed as data column separators in the catalog file.
-
Use the Import at
Line field to set the line number at which to begin
importing data. The first import line is shaded in yellow, as shown
in the picture above. For example, if there are column headings,
you can skip them by setting Import at
Line to 2 or greater.
-
Optional: To save the catalog parameters for
future use, click the Profile control
menu button and select Save As.
-
Click [Import
>>].
-
A summary of imported catalog data is shown in a
Text Editor window. Since a dialog window locks out
other windows while open, you must close both the Import
Photometry Catalog and
Aperture
Photometry Properties dialogs to view the summary in the
Text Editor.
-
Repeat the catalog importing procedure if you
are not satisfied with the result. Close the dialog when
finished.
NOTES:
-
If importing positions by (RA, Dec), the images
must possess a WCS (
World Coordinate System) calibration. Without a
WCS, Mira cannot calculate the (column, row) coordinates in the
images.
-
If the Track
Centroid option is checked on the
Point Markers page, the computed (column, row)
position of each object will be refined by centroiding after
applying its WCS transformation.
Catalog File Details
-
The catalog to be imported must be a text file
(*.txt) consisting of 1 row per object and all properties listed in
columns separated by tabs. Not all columns need to be used during
the import, but you must select which columns contain the data of
interest. As a minimum, the object positions must be imported as
x,y (column, row) values or as (RA, Dec) values. If a property is
unused, select --none-- for its column.
The catalog file can contain any number of lines.
-
After selecting the catalog file, the
Preview grid will show up to 50 columns
and 50 lines of data. From the preview, select the column
assignments using the selectors in the Catalog Data Column
Map.
-
Use the Import at
Line control to skip lines of column heading information in
the import file. The picture above shows the first line of data is
set to line 2. Mira highlights the first import line in yellow as
you change it.
-
Use the Magnitude
selector selects the column containing magnitude information. The
magnitudes of standard stars will be used for photometric
calibration of each image. The magnitudes of other target objects
are ignored and will be updated using this calibration. If no
objects are standard stars, then no calibration is attempted.
-
To identify any of the objects as standard
stars, set the Standard Star? column to
column 4, where the standards must be identified using *, Y, or y (or any word starting with an uppercase or
lowercase Y).
-
An import file containing both standards
and unknowns must have a column dedicated to specifying whether the
object is a standard or unknown. This column is specified in
theStandard Star ? field. The line
for each standard must identify the object as a standard using the
letter Y, y or an*
(asterisk). An object not interpreted as a standard star must
contain a blank character in the same column. The example
above shows column 6 as the standard column and it is blank,
indicating the object is not a standard star.
-
The Weight parameter
is used for computing the photometric zero point for each image.
This parameter applies only to objects identified as standard
stars. If no weight is listed in the file, it defaults to 1.0.
Related Topics
Aperture Photometry,
Aperture
Photometry Properties,
Extract Sources command
Mira Pro x64 User's Guide, Copyright Ⓒ 2023 Mirametrics, Inc. All
Rights Reserved.
|
