These directions apply specifically to supported Celestron mounts. With PEMPro you can:

1.Precisely shift the PEMPro-created PEC curve to tune for camera delays.

2.Upload a PEC curve to the mount PEC table.

3.Download and display the mount's PEC table.

4.Save a PEC curve to a file compatible with Celestron's PECTool format.

5.Read a PEC curve from a previously saved file (by PEMPro or Celestron's PECTool).

6.Perform the initial mount Seek Worm Index.

7.Modify a PEC curve before sending it to the mount. You can:

oShift entire curve

oInvert the entire curve

oScale the entire curve

oSmooth the curve.

8.Fix residual drift in the PEC Curve (this can happen on a PEC Curve created with an autoguider).

9.Turn PEC On/Off.

Also:

1.When you connect to the mount the worm period and phase are automatically determined from the mount.

2.PEMPro automatically re-synchronizes itself before starting to acquire PEC data (you never have to worry about synchronizing). This allows you the freedom to move the mount around without worry of forgetting to re-synchronize.

3.You may be able to use PEMPro's Refine curves procedure to improve PEC further.

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Basic Steps to use PEMPro

You must follow these basic steps to use PEMPro:

1. Use the Mount Wizard to create an instance of a Celestron mount in PEMPro. You only need to do this step once.

2. Once each session before acquiring periodic error data you should run the Calibration Wizard on a star near 0 declination.

3. Acquire 5-6 worm cycles of periodic error data with PEC turned off.

4. Create a PE curve.

5. Upload the curve directly to the mount.

6. Check that PEC is reduced by turning PEC on and acquiring a couple worm cycles of data.

Each of these steps is explained in more detail below:

1. Creating a new mount instance with the Mount Wizard

The first thing you must do is to create an instance of a Celestron mount in PEMPro. The easiest way to do that is with the Mount Wizard. Press F8 or go to the Wizards Menu and select Mount Wizard...

When the Mount Wizard (Step 1) comes up enter a unique name for your mount. When you exit the Mount Setup wizard the name you type will appear in drop down list box to the right of the Connect Scope button on PEMPro's setup tab.

Press Next> to continue. Select Celestron in the drop down list in Step 2:

Click Next> to continue.

When Step 3 is reached the Celestron ASCOM driver should be automatically selected. The next thing you should do is verify your ASCOM driver is setup is OK by clicking Edit Driver Settings. At the time of this writing the latest Celestron ASCOM driver is 4.2.17 and its setup page looks like this (look at the lower left for the version number).

Make sure that at least the Serial Port, Scope Type, and Site Longitude and Latitude are set up correctly.

2. Run the Calibration Wizard before acquiring data

Once every session, before acquiring periodic data, you should run the Calibration Wizard. The Calibration Wizard sets all of the important parameters used by PEMPro to accurately calculate periodic error. Note that you don't need to run this wizard if you are analyzing data previously collected.

Some of the settings established include:

•Telescope declination

•Camera tilt angle

•Which axis of the camera corresponds to Right ascension

•Image Scale

•Telescope movement direction

Before starting the Calibration Wizard you should center a 6th-8th magnitude star in the center of your CCD camera. The star should be just west of due South and at 0 degrees declination or higher if you are in the Northern hemisphere.

If you are in the Southern Hemisphere, the star should be just West of due North and 0 degrees declination or lower. In either case it is best to pick a star within 45 degrees of the celestial equator (in Northern hemisphere: 0 < declination < +45, in Southern Hemisphere: 0 > declination > -45).

Make sure that Adjust Data for Declination is checked in the Settings Menu. While you are at it also make sure that De-Rotate Data is also checked. If either is not checked then enable them.

Connect to the mount press the Connect Scope button on PEMPro's setup page:

If you do not have the latest version of the Celestron ASCOM driver a dialog will pop up warning you of that. At the time of this writing version 4.2.17 is the current version. You can usually get the latest version from:

https://www.ascom-standards.org/downloads.html

In case the 4.2.17 release has not yet been posted you can temporarily download from here:

https://www.siriusimaging.com/PEMPro/CelestronDriver4217.zip

Select your camera control program and connect to your CCD camera by pressing the Connect Camera button. Also, make sure that Use Autoguider Port to Move Scope is unchecked.

To active the Calibration Wizard select its menu option:

If you are not familiar with the steps of the Calibration Wizard then you can find how to use it here.

3. Acquiring Data

Make sure that you are connected to the mount and the CCD camera as described above. You will know you are connected when the scope and camera drop down list boxes are grayed out and the buttons say Disconnect Scope and Disconnect Camera as shown here:

If you get an error connecting to the mount then check that the camera connects OK by manually trying to connect from your camera control program. Once it connects manually PEMPro should also connect successfully.

One other thing you will want to do is to make sure PEC is off. PEMPro has convenient buttons to turn the PEC on and off. In this step we want PEC off so press the PEC OFF button.

Then click the Acquire Data tab and press the Start button:

If you have Ask for Filename and Comments when Acquiring Data checked in the Settings menu, you will have an opportunity to change the default filename and add optional comments to the file. Click here for more details.

Before PEMPro takes any images it automatically queries the mount for the current worm position and synchronizes the data that it is about to collect to the mount's worm phase. This means that you can freely move the mount before acquiring data without the risk of forgetting to synchronize PEMPro to the mount.

The synching process can take up to 5 seconds so while it is happening this dialog will display:

Now, just sit back and let PEMPro collect 5-6 cycles of periodic data. The horizontal axis of the graph is worm phase and the vertical axis is the measured PEC. After each worm cycle the color of the data will change.

Note: The pictures below in this section are for illustration only. They are not from an Celestron mount.

Click Stop when you are done collecting data. If you have Ask for Filename and Comments when Acquiring Data checked in the Settings menu, you will have a final opportunity to add comments to the file or delete the log file and start over. If you don't delete the file you will be prompted to go directly into the create curve dialog:

Click Yes to continue.

4. Create a PE Curve

You can create a PE correction curve immediately after acquiring data or use the log file created in a previous session. PEMPro places all log files in the directory specified in the Logs and Images Dir field on the Setup tab of PEMPro's main window.

When the create PE Curve dialog opens it may take a few seconds to calculate an optimum curve. In most cases you won't need to do any modifications to the curve. Advanced users may wish to add or remove fundamental frequencies to see how that effects the curve's fit, the measure of which is the RMS Error in the upper right of the dialog.

Before leaving this dialog take a moment to check that the Worm Period, Image Roll, Declination, and Image Scale look correct. If anything looks wrong click Cancel and go back to the Setup and Calibration Wizard to setup the parameters again. Otherwise press Create PE Profile and Close if you are satisfied with the curve.

5. Adjust Curve and upload to the mount

After the Create PE Curve dialog closes in the previous step, PEMPro will automatically switch to the Celestron tab and ask if you want to upload to the mount. If you click Yes the curve is immediately uploaded to the mount and you are done!

However, if you are an advanced user you may to click No so that you can first adjust the settings in the Modify PE Curve group. Controls on the Celestron tab are explained below.

At the top of the graph Peak to Peak PE labels the total periodic error of the curve.

While you are connected to your mount and in the Celestron Menu you can directly load a previously created curve. PEMPro automatically creates these curves, which have the extension ".ppc", whenever you use Create PE Curve.

When the curve is loaded it is also automatically shifted by the number of seconds in Phase Adjust. In the example below the curve is loaded and shifted right by 10 seconds (because phase shift is set to 10 seconds).

 

6. Check Corrected PEC

After you upload the new PE correction curve you will want to turn PEC On and acquire at least 2 worm cycles of data. If you see that the periodic error is worse than before you can go back to the Celestron tab and press the Invert Curve button and then click To Mount to send the curve to the mount again. Then start the acquire data again. The mount's periodic error should be significantly reduced.

If, after checking the corrected periodic error of the mount you find that you want to try for further improvement you can use the Refine feature.

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Celestron Tab features

Below is the Celestron tab before connecting to the mount. All the buttons and controls are disabled except the From File button and the Shift and Scale numeric up-down controls. If you click From File you can load in a previously saved PEC curve. The table will then fill with entries from the file and a graph of the curve will display.

Once PEMPro is connected to the mount on the Setup tab, the From Mount and other buttons are enabled. Also the Firmware Rev is displayed:

The From Created PE Curve button is enabled if a curve has been created with the Create PE Curve dialog. Also all the controls will be enabled if a file is loaded with From File, or From Mount is used to read the PE data.

Here is a summary of all of the controls:

From Created PE Curve: loads a PE curve that has just been created or loaded.

A previously created curve (*.ppc) can be loaded through the Refine page. Just load a curve with the Curve 1 button then go to the Program Mount section and press Use Curve. You can then import the curve to the Celestron tab by pressing the From Created PE Curve button:

Phase Adjust: This control allows you to precisely adjust how much phase shift occurs when the From Created PE Curve is pressed. The curve can shift the curve left or right by up to 480 seconds. The value is seconds:

These are the functions you can do to the periodic error curve as a whole:

<-Shift - Shifts the curve left by the number of cells in the Shift Value field. There are 88 cells total which means that for a mount with 480 seconds, each cell is about 5 seconds. So the time shift of one cell is about 5 seconds.

Shift-> - Shifts the curve right by the number of cells in the Shift Value field. There are 88 cells total which means that for a mount with 480 seconds, each cell is about 5 seconds. So the time shift of one cell is about 5 seconds.

Note that since the left hand edge of the graph always starts at 0 the whole level of the curve will change as you shift, however the shape and magnitude of the curve will not change.

Invert - Inverts the entire Periodic error curve.

Smooth - Does a very modest smoothing of the curve. The Smoothing consists of doing a weighted average of each cell with its the two nearest neighbors.

Scale - Scales the curve by the factor in Scale Value. If a curve over or under corrects the periodic error of your mount you could use this to fix the curve without re-acquiring data.

Clear PEC - Fills the entire PEC table with 0's.

Fix Drift - Fixes residual drift in the PEC Curve. This can happen if you trained PEC with an autoguider instead of using PEMPro. PEMPro will never leave residual drift in the curve.

IMPORTANT: After making adjustments to a PEC curve with any of the above buttons you will need to write it to the mount with the To Mount button.