OVSA Explorer is a widget program whose main task is to open and display the contents of an IDL OVSA data file produced by any SSW routine via "analyze.pro" or by OVSA Explorer itself.
The OVSA Explorer menu bar contains the following items:
The File menu contains the following options:
File/Open prompts the user to choose one of the existing "*.sav" files.
The default path of the dialog box is the data directory, which for the first time user is set by default to c:\working\. The user may change the default location of the data directory, or reset it to its default name, by using the Options/Preferences menu item.
If no valid "*.sav" file exists on the local computer, the user may try to download it directly from the OVSA data server following one of the "event" link. If the desired file does not exist in one of the provided lists , the user may try to download the corresponding "*.arc" file and produce the "*.sav" file using the File/Calibrate ARC menu item.
File/Open Next SAV opens the next "*.sav" file, in alphabetical order, from data directory.
File/Restore opens the "*.sav" file from which the currently displayed file has been created, if such a file still exists in the same location. This option is valid only for the "*.sav" files created by OVSA Explorer from an already existing "*.sav" file. Every time the File/Save or File/Save As are used, OVSA Explorer also saves the information regarding the name of the currently open file.
File/Save and File/Save As should be used to save the currently displayed section of the "*.sav" file being analyzed. However, the File/Save command should not be used if one wants to not alter the original "*.sav" file. The default path used by any Save command is the currently defined working directory. The user may change the default location of the data directory, or reset it to its default name, by using the Options/Preferences menu item.
The File/Save As command suggests a default file name in the form "yyyymmdd_hhmm.sav", where "hhmm" represents the starting time of the most recent fit movie, if any. If no fit has been already performed, "hhmm" set by default to "0000" to remind the user that no fitting information will be saved.
For convenience, every time a "*.sav" file is saved, an associate "*.med" file is saved in the same folder under the name "yyyymmdd_hhmm.med". However, the user is prompted if a file with the same name already exists.
To learn how to produce a fit movie go to File/Start Fit.
A "*.med" file only can be saved using the File/Save TP and Movie option.
File/Save TP and Movie saves the currently displayed channel and the most recent fit movie into a "*.med" file. The default file name is "yyyymmdd_hhmm.med", where "hhmm" represents the starting time of the most recent fit movie, if any. If no fit has been already performed, "hhmm" set by default to "0000" to remind the user that no fitting information will be saved. The default path used by any File/Save TP and Movie command is the currently defined working directory. The user may change the default location of the data directory, or reset it to its default name, by using the Options/Preferences menu item.
To learn how to produce a fit movie go to File/Start Fit.
File/Calibrate ARC may be used to extract a segment of solar data from an OVSA raw data "*.arc". Data and calibration information may saved into an "*.sav" file ready to be open in OVSA Explorer. This operation is performed by the OVSA SSW widget WCalibrate.
File/Quit closes the current session of OVSA Explorer.
The Mode menu allows the user to change the operating mode of OVSA Explorer according with the task to be performed. Each specific mode is indicated by a particular cursor and by the mode name displayed by the OVSA Explorer Mode textbox. The following modes are available:
Mode/Explore sets the Explore mode, which is the basic operating mode of OVSA Explorer. In this mode the mouse may be used to zoom in the dynamic spectrum window or the light curve window, using a rubber band box, or to zoom out, by clicking the left mouse button when inside one of these two windows.
Mode/Set Background sets the Set Background mode, which can be used to set up to 10 background intervals to be used to compute the background to be subtracted from the dynamic spectrum.
If only one interval is set, the averaged flux in for each frequency is computed. If more than one interval is set, a n-degree polynomial is used to fit the background at each frequency, where n is the number of background intervals.
Each fit interval is initiated and ended by a left click, either in the dynamic spectrum window or in the light curve window. The latest background interval set can be removed by clicking the right mouse button.
To subtract the selected background from data, the user must select the Apply Background checkbox. This operation can be reverted by deselecting this checkbox.
WARNING: If the background is subtracted before saving the "*.sav" file, the operation cannot be reverted in the next session. However, if the new file is saved under a different name, the original file may be restored using the File/Restore option.
Mode/Set Fit Intervals sets the Set Fit Intervals mode, which can be used to set any number of frequency intervals to perform an independent spectral fit for each of these intervals, or to remove any of the previously defined fit intervals.
The fit intervals already defined are indicated by pairs of dashed (the lowest frequency) and dotted (the highest frequency) lines on both dynamic spectrum and spectral windows.
Once in the Set Fit Intervals mode, there are two ways to define these intervals: automatically and manually.
To automatically define the fit intervals, please make sure that the following conditions are satisfied:
The previously defined fit intervals can be removed at once using the Tools/Remove Fit Intervals option.
If the Fit checkbox is selected and the mouse points in the dynamic spectrum window, OVSA Explorer displays in the spectral window the fit result obtained for a number disjointed of fit intervals defined using a predefined algorithm.
Moving the mouse over the dynamic spectrum, the fit intervals are recalculated for each moment of time pointed.
If a reasonable set of fit intervals is found by these means, by clicking the left mouse button, the currently displayed fit intervals are saved and applied for the entire dataset.
After the first mouse click, the mouse can be moved over the dynamic spectrum window to check the fit results for the currently defined fit intervals at any instant of time.
If the results are not satisfactory, the automatically defined fit intervals can be removed using Tools/Remove Fit Intervals, and the operation can be repeated, or the user can try to manually set the fit intervals.
To manually set the fit intervals, please make sure that the following conditions are satisfied:
Any number of fit intervals may be defined or added to the existing ones by clicking the left mouse button in the dynamic spectrum window when the desired frequency is pointed out. The frequency currently pointed is shown by a vertical solid line in the spectral window.
Two consecutive clicks define one frequency range which is indicated by a pair of dashed (the lowest frequency) and dotted (the highest frequency) lines on both dynamic spectrum and spectral windows.
The frequency ranges manually defined may overlap or have common boundaries.
Although there is no restriction in the number of frequencies included in a given fit interval, since the fitting model is a four parameter function, no spectral fit can be performed for those intervals including less than four frequencies.
To remove the fit intervals already defined, one may use the Tools/Remove Fit Intervals to remove all at once, or a right mouse click inside one interval, when in the dynamic spectrum window and in the Set Fit Intervals operating mode , to remove a specific fit interval.
When manually removing the fit intervals, one should have in mind that the overlapping intervals are internally defined in different layers, the most recently defined interval being the closest one to the user and the first to be removed by clicking the right mouse button inside its boundaries.
WARNING: When removing a fit interval, one should be aware that the operation will also remove any peak interval associated with the fit interval being removed.
Mode/Set Peak Intervals sets the Set Peak Intervals mode, which allows the user to define or remove any number of compact time intervals. This option may be useful in the case of complex time structures, when separation of individual temporal peaks is desired.
Since any temporal peak is associated with a given fit interval, this action is active only if at least one fit interval has been already defined. To define a fit interval, see Set Fit Intervals.
Any number of peak intervals may be defined or added to the existing ones by clicking the left mouse button in the dynamic spectrum window, inside the frequency range to be associated with. The time moment currently pointed is shown by a vertical solid line in the light curve window.
Two consecutive clicks inside the same frequency range define one time interval, which is indicated by a pair of dashed (starting time) and dotted (ending time) lines on the dynamic spectrum window, and on the light curve window, if the frequency selected belongs to the fit intervals in which the time interval has been defined.
The time intervals defined may overlap or have common boundaries. If the mouse point out a frequency belonging to more than one frequency ranges (overlapping fit intervals), a separate time flag is defined in each frequency range.
To remove a time interval already defined, one should click the right mouse button inside the time interval to be removed.
All time intervals associated with a given frequency range (fit interval) may be removed at once by removing the fit interval itself.
Mode/Flag Bad Freq may be used to flag one or more frequency channels having bad quality data. The flagged channels are discarded from any analysis by being filled with NaN (not a number) values, which appear in black on in the dynamic spectrum window. Flagging a bad frequency is a ?reversible operation. However, to recover a given flagged channel one should make sure that the time resolution mode of OVSA Explorer is the same as the one in which the same channel has been flagged.
To flag a frequency channel, once in the Flag Bad Freq mode, click the left mouse button in the dynamic spectrum window in any point belonging to that frequency channel.
To recover a flagged frequency channel, once in the Flag Bad Freq mode and in the same time resolution mode as used when the channel has been flagged, click the left mouse button in the dynamic spectrum window in any point belonging to that frequency channel.
NOTE: If the file contains a frequency previously flagged in a different time resolution mode, the Flag Bad Freq menu item is automatically deactivated. To make this option available, the original time resolution mode must be firstly set. To change the time resolution mode in which the frequency channels are flagged, all previously flagged frequency channels should be firstly recovered before changing the time resolution mode.
The Tools menu contains the following options:
Tools/Remove Fit Intervals may be used to remove all the fit intervals, and their associated peak intervals, already defined.
Tools/Show 3D for TP Median calls the IDL widget XSURFACE to produce an interactive 3D plot of the median dynamic spectrum. The X and Y axis correspond to the time en frequency variables, while the Z axis represents the median flux density.
Tools/Show FLAREMETER scan displays a "*.png" image representing the output of the FLAREMETER monitor for the given data segment. If such a file does not exist in the working directory, the user is allowed to find it manually. This option may be useful in finding the flare regions automatically detected by FLAREMETER.
The original FLAREMETER outputs, daily produced at OVSA site, can be viewed online at http://www.ovsa.njit.edu selecting the appropriate date under the section DATA/OVSA. The "*png" image corresponding to a specific data segment (yyyymmdd_hhmm.png), or to the entire day (yyyymmdd_all.png), can be downloaded, starting with January 2000, from http://www.ovsa.njit.edu/data/gifs/.
The Fit menu contains the following options:
The Options menu contains the following options:
Options/Preferences launches WPreferences widget to allow the user to setup the default paths to be used by OVSA SSW applications. The current path structure may be viewed at any time using the command line statement: help, !defaults, /struct.
The preferred paths used by default by OVSA Explorer are:
!defaults.datadir -the default path used by File/Open or File/Open Next SAV commands.
!defaults.workdir -the default path used by File/Save, File/Save As or File/Save TP and Movie commands.
Options/Log Scale may be used to check/uncheck the option of displaying the dynamic spectrum and the light curve plot in logarithmic scale.
Options/Force Zero may be used to check/uncheck the option of fixing the minimum flux value at zero in the dynamic and light curve windows.