2 replies to this topic

[batmanbeginz]

I recently purchased a ETX80 AT for $50 on FB marketplace. I already own Virtuoso GTI 150 GOTO so this was just a random purchase because of Goto + Portable Scope idea.

 

I cleaned the battery compartment and powered it with an external power supply since the initial battery compartment was corroded.

The motors seems to be working fine. I noticed after the alignment when the telescope is idle and tracking an object, it has these strange hum/beep noises which drives me crazy.

Its not super loud but I was thinking if there is any way to contain this noise?  

 

Should I open the motor drive and apply any lubricant? I also saw on some forums recommendation to apply sound absorbing foam.

Any suggestions are welcome, regarding this or making the best use of this scope.

 

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[Thrifty1]

That “chirping” sound is normal and comes from digital motor servos that drive the Dec and Alt. Unfortunately there is little you can do to eliminate it.

I’m not sure why the engineered it like this as other telescopes such as Celestron Mak's and SCT’s don’t make this sound.

[deSitter]

It's because the plastic housing is basically a speaker On my ETX105, which has a metal superstructure with a plastic skin, the noise is very much suppressed - there isn't enough free space in the housing to resonate like a speaker.

 

I was really annoyed at first, but have come to enjoy the gentle grinding noise made by my ETX90. It's sort of like a motorcycle, you can tell how it is operating by the sound of the engine(s).

 

If you want to try a fun experiment, do an indoor 2-star alignment - just hit ENTER when asked to center the alignment stars - then go-to Polaris, which is very near the celestial pole, so has very little second-to-second motion. Listen to the tracking.

 

A second experiment is to find an object which will transit through or very close to the zenith. Listen to the tracking as the scope tracks the object near the zenith. It's amazing to watch the scope just suddenly start hauling *** to do the switch from east to west!

 

-drl