iOptron IEQ45TM instruction manual PEC Option, Pole Star Position, PEC Playback, Record PEC

Follow the on-screen instruction to bring the object back to center again and press ENTER. The screen will show

R.A. anti-backlash 0250 steps

Save test value?

If you want to save this anti-backlash number, press ENTER. Otherwise press BACK. This will bring the hand controller to DEC backlash testing screen. Follow the on-screen instruction to test the DEC backlash.

5.5.6. Pole Star Position

This shows Polaris position in northern hemisphere or Sigma Octantis position in southern hemisphere, which is used for Quick Polar Alignment.

5.6. PEC Option

5.6.1. PEC Playback

You can turn “PEC Playback On” while you do the tracking, especially for long time astro- photography. A “PEC” indicator will displayed on the LCD main screen when it is turned on. The default status is PEC Playback Off when the mount is turned on. It is not recommended to use PEC Playback while autoguiding.

5.6.2. Record PEC

All Equatorial mounts have a small variation in the worm gears which can be corrected by using Period Error Correction or PEC. PEC is a system which improves the tracking accuracy of the mount by compensating for variations in the worm gear and is especially useful when doing astrophotography without autoguiding. Because the variations are regular, it is possible to record the corrections required to cancel out the worm gear variations and to play them back.

In order to use the PEC function, the Go2Nova hand controller needs to record the PE first. The periodic error of the worm gear drive will be stored and used to correct periodic error. There is no need to record the PE value again unless it is necessary, such as wearing of worm gear after extended use.

Here’s how to use the PEC function.

1.Setup the mount with a telescope in autoguiding condition by connecting a guiding camera to a computer via ST-4 autoguiding port or ASCOM protocol;

2.Press MENU, select “Auto Guide” and press ENTER. Select a guiding speed from 0.20X to

1.00X;

3.Then press the BACK button and select “PEC Option” from the menu. Use the ▲ and ▼ scroll buttons to display the “Record PEC” option and press ENTER to start record the PE.

4.It takes the worm gear 400 seconds to make one complete revolution. After 400 seconds PEC will automatically stop recording. The PEC value will permanently stored inside PEC chip on R.A. motor drive until a new data are recorded.

5.If you want to re-record the periodic error, select “Record PEC” and repeat the recording processes again. The previously recorded information will be replaced with the current information.

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