User's Manual

5.5. Electric Focuser

This function controls an iOptron electric focuser.

5.6. PEC Option

This function only works for a standard CEM70 and CEM70G mount.

5.6.1. PEC Playback

You can turn “PEC Playback On” to improve tracking accuracy which is especially useful for

long exposure astrophotography. The default status is “PEC Playback Off” when the mount is turned

on.

5.6.2. Record PEC

All equatorial mounts have a small variation in the worm gears which may 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 to correct the periodic error caused by the

variations.

In order to use the PEC function, the Go2Nova

hand controller first needs to record the

periodic error. The periodic error of the worm gear drive will be used to correct periodic error.

We recommend using a guiding camera to record the PE with autoguiding. Here’s how to use

the PEC function:

1. Setup the mount with a telescope in autoguiding configuration by connecting a guiding

camera via the mount’s Guide Port or using the ASCOM protocol;

2. Select “MENU=>Settings => Set Guiding Rates”. Set a guiding speed from 0.10X to 0.90X.

The default setting is 0.50X;

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 recording the periodic

error.

4. It takes the worm gear 348 seconds to make one complete revolution. After 348 seconds

PEC will automatically stop recording. The PEC value will be 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.

5.6.3. PEC Data Integrity

This function will check the recorded PEC data integrity.

5.7. Park Telescope

This function parks the scope to one of four preset park positions.

5.8. Edit User Objects

Besides various star lists available in the hand controller, you can add, edit or delete your own

user-defined objects. This is especially useful for newly found comets. You can also add your favorite

observation object into the user object list for easy sky surfing.