Ephemeris Interpolator has buttons on the Pad window to send calculated information for speed, P.A.° and also RA and Dec to Astrometrica automatically, rather than manually keying in the information, making the Astrometrica stacking process quicker, more streamlined and reducing the chance of typing errors.


To reduce the amount of manual interaction to a minimum during stacking operations, FITs files selected in Astrometrica for stacking can also be dragged onto the Pad, causing the mid-time of the files to be automatically determined and used to calculate fresh values for speed and P.A.°, then automatically completing the stacking procedure in Astrometrica without further user interaction.


There are three menu options in Astrometrica that Ephemeris Interpolator is designed to integrate with:


  • Astrometry / Track & Stack ... (Ctrl+S)
  • Astrometry / Data Reduction ... (Ctrl+A)
  • Astrometry /  Moving Object Detection ... (Ctrl+M)


Note: In the examples below it is assumed that the Ephemeris Interpolator has already been loaded with an ephemeris for the object being processed in Astrometrica, the year, month and day have been entered in the Date, Time boxes and the Undock and minimise button on the main Ephemeris Interpolator window has been pressed to display the Pad.


Stack images by drag and drop (for Track & Stack only)

Sending Speed and P.A.° to Astrometrica (for Track & Stack only)

Sending RA and Dec to Astrometrica (for Track & stack, Data Reduction and Moving Object Detection)

Locating the running Astrometrica application


Stack images by drag and drop

Images can be stacked in Astrometrica by dragging the files to be stacked from the Astrometrica Select images window and dropping them directly onto the Pad.

The mid-time of the dropped images is determined and used to calculate the Speed and the P.A.° of motion before sending them back to Astrometrica to automatically complete the stacking operation.

The method of stacking (i.e. Add, Median or Average) can be set in the Pad beforehand, or can be set during the drag and drop operation. See Stacking method.



Detailed steps:


  1. Ensure an appropriate ephemeris is loaded and selected in the main Ephemeris Interpolator window covering all the times likely to be needed for the track and stack operations.
  2. Press theAstrometrica Stack images toolbar button to display the Select Images dialogue
  3. Press Add on the Select Images dialogue
  4. Select all the files that are to be stacked in the resulting Open dialogue
  5. Start dragging the selected files from the Open dialogue by positioning the mouse over the selected files, then hold down the left hand mouse button and move the mouse. The mouse cursor will change to indicate that a drag operation is in progress
  6. Still holding the left hand mouse button down, move the mouse over the Pad (see Note below if the Pad is not visible, or if the wrong ephemeris is selected)
  7. If the stacking method needs to be changed then hover the mouse over the required method (Add, Med or Avg) for a short time before dropping the files
  8. Drop the files by releasing the left hand mouse button with the mouse anywhere over the Pad
  9. Dropping the files automatically causes the following actions:
    • The date and time on the Pad will be refreshed with the mid-time of the dropped files and the RA, Dec, Speed and P.A.° recalculated for that time
    • The Track and Stack operation in Astrometrica will then continue, using the updated Speed and P.A.° values. 


Note:

  • When the drag operation is started in step 5, if the Pad is not visible but the main Ephemeris Interpolator window is, drag the files over the main window, still keeping the left hand mouse button pressed. The Pad will automatically be displayed, proceed from step 7 above.
  • If neither the Pad or the main Ephemeris Interpolator window are visible, then drag the files over the Ephemeris Interpolator icon on the taskbar, keeping the left hand mouse button pressed. Hold the mouse there until the main Ephemeris Interpolator window is displayed and if the Pad had not already been minimised, the Pad will also appear. Proceed from step 7 above.
  • After starting a drag and drop operation, if the wrong object is selected in the main form, the desired ephemeris tab can be selected by hovering the mouse over it for a short time, before proceeding from step 7 above..


Mid-time calculation for dropped files: The exposure start time and length are extracted from the metadata contained in each .FITs file and used to calculate the overall mid-time for the selected files. The calculation checks the CCD program settings in Astrometrica for 'Time in File Header' to ensure the correct start time is calculated.

Sending Speed and P.A.° to Astrometrica

During Astrometrica Track & Stack processing, the Speed and P.A.° are requested from the user in the Coordinates, Tracking and Stacking window:



The mid-time for the images being stacked is given, in the example above, 19:47:24 UT.


In Ephemeris Interpolator:


The Ephemeris Interpolator re-calculates the Speed and P.A.° for the time entered, then sends the values to the Astrometrica Coordinates, Tracking and Stacking window and starts the stacking process in Astrometrica.


Here the initial mouse click, movement of data and eventual stacking in Astrometrica are emphasised to highlight the actions taking place:



This integration is unsophisticated and involves automatically sending keystrokes from Ephemeris Interpolator to the Astrometrica window. This requires that, after pressing the Paste speed and P.A.° to Astrometrica button the keystrokes are allowed to complete before using another Windows application, otherwise the keystrokes may not arrive in Astrometrica and so the process may need to be repeated.


The keystrokes sent to Astrometrica are defined in the AstrometricaSendKeysStack1 and AstrometricaSendKeysStack2 settings. These keystrokes have been tested to work successfully with Astrometrica versions 4.11.1.442 and 4.12.0.448. If other versions of Astrometrica require different keystrokes then these two settings may need to be updated accordingly. See the extended description from the Settings screen for details of the special keys and modifiers that can be specified.


After sending the values of Speed and P.A.° to Astrometrica (using keystrokes defined in AstrometricaSendKeysStack1) the process pauses for a number of seconds defined in setting AstrometricaStackDelay, so that the user can have time to see the updated values in Astrometrica, before sending the second set of keystrokes defined in AstrometricaSendKeysStack2, causing the Coordinates, Tracking and Stacking window to disappear. The default delay is 1 second, reduce or increase as required.

Sending RA and Dec to Astrometrica

When images are being processed in Astrometrica but the RA or Dec in the FITS headers are incorrect or missing then Paste RA and Dec to Astrometrica button can be used to automatically replace the Right Ascension and Declination coordinates in Astrometrica with the RA and Dec calculated in Ephemeris Interpolator.


This applies to two Astrometrica windows:

  • the Coordinates, Tracking and Stacking window, invoked using the Astrometrica menu option Astrometry / Track & Stack ... (Ctrl+S)
  • the Coordinates window, invoked using the Astrometrica menu options Astrometry / Data Reduction ... (Ctrl+A) or Astrometry /  Moving Object Detection ... (Ctrl+M)


In Ephemeris Interpolator:


The Ephemeris Interpolator re-calculates the RA and Dec for the time entered, then sends the values to the Astrometrica Coordinates or Coordinates, Tracking and Stacking windows.


No further processing is initiated automatically in Astrometrica (unlike when sending Speed and P.A.°), so:

  • On the Coordinates window press OK to continue
  • On the Coordinates, Tracking and Stacking window either:
    • press OK to start the Track & Stack process if the Object motion details are OK, or
    • use the Paste speed and P.A.° to Astrometrica button to also update the Object motion values before continuing


Note: If the FITS files being processed can be relied on to have accurate RA and Dec information in their FITS headers then the Paste RA and Dec to Astrometrica button can be disabled to stop it being inadvertently pressed, by changing the AstrometricaEnableSendRADec setting to False.

Locating the running Astrometrica application

When keystrokes need to be sent to Astrometrica, Ephemeris Interpolator tries to locate the currently running Astrometrica process so that it can prepare it to receive the keystrokes. This normally happens without problem, even if Astrometrica is closed and re-opened, but to force Ephemeris Interpolator to re-locate the Astrometrica process, hold the Ctrl button while clicking on either Paste speed and P.A.° to Astrometrica or Paste RA and Dec to Astrometrica buttons.


If Astrometrica is not running then the main Ephemeris Interpolator window message area will display "Astrometrica.exe not located".

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