The information within brackets [ ] is either the default value or the last value selected. Pressing <Enter> without typing anything automatically selects this value. |
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Command |
Command
Description |
Machine response to Command |
Information
returned after Command execution and before machine response |
Type xselect to begin |
Launches xselect program |
>Enter session name [xsel] | |
[xsel] | Designates file save
location when you exit xselect |
Displays that xselect is setup for ASCA, time keyword is TIME in units seconds, and the default bin size |
|
Type read events at the new prompt |
Tells xselect that you want to
open an Events ("evt") file. |
>Enter the Event file dir [./] | |
[./] | Specifies the location of the
Events file
to be analyzed |
>Enter the Event file list [acis...fits] | |
[acis..._evt2.fits] |
Selects Event file you want to
open. |
Got new mission [axaf) > Reset the mission ? [yes] |
|
[yes] |
Resets the (observatory) mission. |
Displays that xselect is now
setup for AXAF (aka Chandra), time units, and Default Binsize. Also displays settings commands, and the location of the file, object name, date it was observed, exposure time ( = LIVETIME). [note: mission can also be reset by typing set mission and then by typing AXAF in response to which mission?] Default Binsize (or minimum time resolution) should match that in image header. If minimum time resolution is not recognized, execute next command |
|
Type set binsize |
Manually resets the minimum time
resolution |
Give bin size in seconds [16.000] |
|
1.24104 |
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Image Analysis |
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At the new prompt type extract image |
Extracts the image you selected
from the Events file. |
Shows total events (photon
counts) written for the exposure time
period; reports average counts/sec ; a high rate means the image is bright, a low rate means the image is faint. |
|
Type saoimage |
Opens the extracted file in ds9. |
For more help with
ds9 visit short
guide to ds9. |
|
|
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Type filter region ds9.reg |
Takes the region you just
selected in ds9 and blocks out surrounding image |
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Type extract events |
Extracts events from the Event
File. |
equivalent to "extract image"; see above |
|
Examining light
curves |
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Type extract curve |
Extracts light curve data. |
equivalent to "extract image"; see above |
|
Type set device /xw |
Sets device to /xw, just as in
lcurve routine |
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Type plot curve |
Opens plot window with graph. |
||
To rescale graph on x axis type rescale
x xmin xmax , with xmin and xmax being the numbers you want for
the scale. To rescale graph on y axis type rescale y ymin ymax. |
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Type exit |
Exits out of PLT> window, and
returns to xselect prompt. |
||
Type save curve |
Tells xselect you want to save
your light curve. |
Give output file [lcurve] | |
Designates file path to save in,
default is last save name. |
lcurve88 |
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Extracting
a power spectrum (these commands are nearly the same as those for the powspec routine) |
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Type $ |
Temporarily leaves xselect. (type exit to return to xselect) |
||
Type powspec filename.lc |
Opens the light curve file you
just saved, filename being whatever you named it. |
Name of the window file ('-' for default window). |
|
Type - |
Tells xselect what window file
you want to use. |
Newbin Time or negative rebinning [3.241] |
Displays Minimum Newbin Time(s); this should match time resolution Displays Default Newbin Time (which must be an integer multiple of the Minimum Newbin Time); Default Newbin Time chosen so that number of bins is close to an integer power of 2 (helpful for Fourier transform?) |
3.2410400 | Tells xselect what you want the
Newbin Time to be, enter the minimum. |
Number of Newbins/Interval [14433] | Confirms the Newbin Time entered. Displays number of Newbins covering the exposure time interval. |
14433 |
Tells xselect what you want the
Number of Newbins per Interval to be, enter the maximum. |
Number of Intervals/Frame [1] | Confirms number of Newbins and Newbin TIme interval. |
1 |
Tells
xselect that all data should be collected in one inteval of time |
Rebin results? |
Confirms that all data will be collected in 1 interval. |
0 |
(allows
another opportunity for rebinning?) |
Name of output file? [powspec_objectname] |
|
powspec_objectname | write powerspectrum filename |
Do you want to plot your results? [yes] | power spectrum file has .fps
extension |
yes |
plots power spectrum |
Enter PGPLOT device [/xw] |
|
/xw | Power Spectrum Ready! |
||
Under the PLT> type hardcopy |
Saves the power spectrum file
and closes the window |
||
Type exit |
Exits PLT> and returns to
xselect prompt |
||
Extracting an energy spectrum from the light
curve |
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Type xselect |
Re-enters the xselect prompt. |
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Enter session name [xsel] | Will designate file save location when you exit xselect | xsel |
Displays that xselect is setup for ASCA, time keyword is TIME in units seconds, and the default bin size |
Type read events in the new prompt |
Tells xselect that you want it to open a file. | ||
Enter the Event file dir [./] | Designates where the Event file
you want analyzed is located, enter the same as before. |
./ | |
Enter the Event file list [acis...fits] | Selects Event file you want to
open. Default is the last opened event file in xselect, use the same as before. |
acisf00088N001_evt2.fits | |
Reset the mission? [yes] Type yes |
Resets the mission. |
Displays that xselect is now
setup for AXAF, time units again, and Default Binsize again. Also displays settings commands, and finally, it shows the location of the file, object name, and date it was observed. |
|
Now type extract spectrum |
Extracts the data needed for the
energy spectrum. |
||
Type plot spectrum |
Plots the spectrum on a graph. |
||
Type exit |
Exits PLT> prompt. |
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Type save spectrum |
Tells xselect you want to save
the spectrum. |
||
Give output file name? |
Enter a file name. This
file is saved as filename.pha,
filename being whatever you pick. |
powspec1943 |
|
Type exit to quit xselect. |
Tells xselect you want to quit. |
||
Save this session? |
Type yes |
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Time
Filter with cursor |
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After a light curve graph has
been plotted type exit under
the PLT> prompt. |
Exits out of the plot window and
returns to xselect |
||
Type filter time cursor. |
Tells xselect you want to break
down the file into intervals of your choosing. |
Opens plot window again. |
|
At PLT> type quit again |
Re-opens plot window with a
cursor selector. Click once where the left boundary will be and
click again where the right boundary will be. |
||
Type x in the plot window. |
Sets the points. |
||
Type exit in the PLT> prompt. |
Exits back to xsel prompt. |
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Type save curve. |
Tells xselect that you want to
save your curve. |
||
Give output file [default] |
Type the filename that you want
to save it as. |
1943split1 |
|
Time
Filter with numbers |
|||
After you have a light curve
extracted and plotted type exit
at the PLT> prompt. |
Exits out of the plot window and
returns to xselect. |
||
Type filter time scc under the xsel
prompt. |
Tells xselect you want to select
times by numbers. |
||
When the plot window opens type quit. |
To quit the plot screen. |
Brings up prompt asking what
starting and stopping times you want. |
|
Prompt asks what your starting
and stopping times are. |
Enter starting time, and
then enter your stopping number, with a , separating the two times. |
0, 928 |
xselect will save the file |
Type save curve. |
Tells xselect that you want to
save your curve |
||
Give output file [default] |
Type the filename that you want
to save it as. |
1943split1 |