Find variables (dialog)

The “Find variables” dialog is used to find objects that significantly change their brightness.

Activating the dialog

The dialog can be activated:

  1. from the main menu: Tools ‣ Find variables.

  2. from the main toolbar: varfind_icon

The dialog controls

Find variables dialog

The dialog for finding new variable stars

(1) The mag-dev graph is presented here. Each point in the graph corresponds to an object. Left click on a mag-dev graph to select a star. The selected star is highlighted and marked as “var”. Its position is shown on the chart (3) and its light curve is shown below (2).

(3) Position of the variable star and the comparison star are marked on the chart. You can also select an object by using the left button. The object is highlighted and marked as “var”. The corresponding point on the mag-dev curve is shown on the graph (1) and it light curve is shown below (2).

When the dialog is opened, it works in the variable selection mode. A suitable comparison star is determined automatically and kept fixed. When you click on the chart or mag-dev curve, you change the object that represents the variable star. To change the comparison star, click on the Change comparison button (5). When the button is pressed, you can change the comparison star by selecting the object on the chart or mag-dev curve. Click the Change variable button (4) to switch back to the variable star selection mode.

Check the Ensemble photometry to allow selection of multiple comparison stars. Click on the icon with the plus sign and click on an object on the chart or the mag-dev curve to add the object to the set of comparison stars. Click on the icon with minus sign and click on a comparison star on the chart to remove the object from the set.

(6) You can save the current selection of comparion and variable star for further inspection. Click the Save as… button. A new dialog appears. Enter a caption that the current selection will be identified with. Using the selection field, you can browse the saved selections and using the Remove button, you can remove the current item from the list.

(7) Using this selection field, you can change the current aperture.

Click the Save chart button (8) to save the chart to a file.

(9) The labels on the X axis can be switched between Julian date (JD) and date and time (UTC).

The magnitudes can be switched between two modes:

  • Adaptive - the magnitude scale of the light curve changes when you change the selection of the variable or the comparison star. The program sets the scale to correspond to the range of data points in the actual light curve for the selected comparison and variable stars. If the range of data points is less than 0.05 mag, the scale is set to cover that range.

  • Fixed - the magnitude scale of the light curve does not change when you change the selection of the variable star. The program makes light curves for the chosen comparison star and all other objects and finds the maximum range D (difference between maximum and minimum magnitude of data points). If D is less than 0.05 mag, it is set to this value. When a user selects a variable star, the light curve is made. The vertical scale of the graph is set to cover the fixed range D and the light curve is shown at the center of the graph area.

Click the “Save light curve” button (10) to save the light curve to a file.

The menu bar that is attached to the dialog provides following functions:

  • Menu File:

    • Save mag-dev curve - exports table with mag-dev curve to a text file.

    • Save chart - save the chart to a file.

    • Save light curve - save the light curve to a file.

    • Export varfile data - exports magnitudes of all stars for all source frames to a single file.

    • Export mag-dev curve as image - exports the graph with mag-dev curve to an image file

    • Export light curve as image - exports the graph with light curve to an image file

    • Rebuild - reloads the data from the project

    • Close - close this window

  • Menu View:

    • Image only - show only CCD image (if available) and hide objects.

    • Chart only - show only objects and hide the CCD image.

    • Chart and image - show CCD image on the background and objects as an overlay.