Paramount ME II GEM

See the Paramount Limited Warranty page for details about what's covered.

Paramount's equipped with on-axis absolute encoders know where they are at all times.  Paramount's with incremental encoders know only how far they have moved since they were initialized using a nightly process called homing..

The crucial additional difference is that the on-axis absolute encoders are fitted directly to the mount axes themselves, bypassing the worm drives.  Paramount's with incremental encoders are fitted to the worms instead, which means that with incremental encoders alone, periodic errors in the worm drive show up in the tracking.

These mounts must be calibrated and corrected using a process called periodic error correction (PEC), which predicts the repeatable error and removes it.  TheSky includes exceptional PEC calibration.

For mounts with incremental encoders, homing re-zeros the encoders when precise sensors on each of the axes are reached. From then on, the incremental encoders are in effect delivering absolute readings.

However, the crucial additional difference remains, namely that the encoder system is behind the worm drive, and periodic error correction is required to get the best out of the RA tracking.

Note that high-resolution on-axis absolute encoder technology is more expensive than using incremental encoders.

All gear-driven Paramounts are equipped with incremental encoders. For the Paramount ME II and the Paramount Taurus 400 models, we offer optional on-axis absolute encoders.

We’re often asked about whether on-axis absolute encoders are required for superior pointing and tracking performance. The short answer is “no.”

Those who purchase our ME II or Taurus 400 mounts for their observatory are usually advanced amateur or professional astronomers — and the vast majority of them opt out of ordering the on-axis absolute encoders.

While on-axis encoders are expensive, that’s not why over 85% of ME II and Taurus 400 buyers decline to use them.

Paramounts have exceptionally small and consistent periodic error.  After applying a one-time software-based periodic error correction procedure, the corrected periodic error becomes negligible.

And, while on-axis absolute encoders permit the mount to always know where it is at all times, Paramounts’ with incremental encoders offer a process called homing that allows them to always know where they are, until they are turned off.  The next night, power on, issue the find home command, and your incremental encoder-based mount is ready to start observing.

Over the years we’ve found that many who ask us about on-axis encoders have basic misunderstandings about what they can and cannot do.

For example, many believe that a mount with on-axis encoders is all that’s needed to have exceptional pointing and tracking when nothing could be further from the truth. All telescopes have inherent errors —for example, mechanical and optical misalignments, and telescope flexure. (For details about that, please visit our TPoint™ page.)

Paramounts use TheSky and TPoint to calibrate the mount + telescope + equipment to create a pointing model.  The pointing model automatically corrects these both pointing and tracking errors (we call that ProTrack™). TPoint is the essential ingredient of TheSky™ that makes the Paramount’s outstanding pointing and tracking possible.

If we were to one day offer on-axis encoders for our smaller gear-driven Paramounts, we’ll be sure to keep them optional so that you will not be forced to pay for capabilities you may not need or want.

With that said, the on-axis absolute encoders offered for the Paramount ME II or Taurus 400 are the highest quality available and provide exceptional performance.

See the Paramount Lubrication Video for details how to lubricate gear-driven Paramount mounts.  (Log in required.)