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Sky-Watcher EQ5 PRO - Is it Noisy?

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#26 deSitter

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Posted 10 September 2009 - 12:50 PM

Part of it is the motors, part of it is how they are mounted. My SVP with these motors was fairly quiet in RA but noisy in Dec, with the Dec motor being mounted directly to the saddle, allowing vibration to radiate into the OTA with not a lot of damping before it gets there. The non-H EQ5 will also have this issue.

Another thing, the CG-5 trick of slewing manually at a slower speed to get quieter operation doesn't really work for these stepper motors, they are very close to the same loudness at any of the slewing speeds from 6-10 I found. And of course the loudness lasts longer at speeds less than 10.

My opinion is the OP should not consider anything other than HEQ*/Atlas/Sirius if they are concerned about noise.

Mike


It's servo motors vs. stepper motors. Former are much louder esp. mounted in a plastic bass reflex speaker enclosure.

-drl

#27 kohudson

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Posted 10 September 2009 - 01:19 PM

Charlie - I think your analysis of my analysis paralysis is spot on. :ooo: I agree - I need to hear the mounts in question to really make a decision. And, in the end, I bet I end up spending a bit more money...

Thanks everyone!

Ken

#28 cdndob

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Posted 10 September 2009 - 02:10 PM

Just to give an idea on how much noise an EQ6 mount puts out I did a quick measurement with my sound meter. The meter was held 12 inches from mount pointing directly at it.

Ambient Noise (inside house) 50-52 db
EQ6 tracking 50-52 db (the slight woosh - woosh noise)
EQ6 DEC, maximum speed, start of slew peaked 58 db
EQ6 DEC, maximum speed, slewing 54 db
EQ6 RA, maximum speed, start of slew peaked 66 db
EQ6 RA, maximum speed, slewing 57 db

And for reference my normal talking voice reflected from the mount to the meter registered 66-70 db.

Steve

#29 Charlie Hein

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Posted 10 September 2009 - 02:29 PM

I didn't say my SVP was as loud as a CG-5, all I'm saying as the Dec motor noise was likely louder than it would be on one of the newer-design mounts where the Dec motor is tucked deeper within. Personally, it exceeded my tolerance, whereas the RA motor noise I could live with.


Sorry Mike - I truly didn't intend to raise a ruckus and I certainly do get your point about this being a matter of personal tolerance. I was just trying to show that for one, the EQ5P should be less noisy than a CG5 (if the OP knows what that sounds like then at least there's some sort of frame of reference to work with) and also that for the money we're talking about it is probably going to be pretty hard to find anything that's significantly quieter than what the EQ5P should be.

#30 hudson_yak

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Posted 10 September 2009 - 03:25 PM

No problem, and I agree with your points here. I'd really like to hear a CG-5 sometime, it must really be...something.

Back when I was trying to make my SVP more quiet, I got dba readings of 70 in RA and 73 in Dec (steady slew, after startup).

Mike

#31 HUsher

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Posted 10 September 2009 - 04:55 PM

I'll go and turn my CG5 on now for you - you'll probably hear it from there :grin:

Helen

#32 ccs_hello

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Posted 10 September 2009 - 07:12 PM

Ken,

EQ5 Pro should not be too noisy at all. Yes, the mount is an EQ5-type but the drive electro-mechanics is completely different.

It is almost the same as EQ6 and HEQ5 Synscan's. At the full slew speed, the stepper should have the same (almost the same) RPM as EQ6/HEQ5's. It's because the intermiate spur gears and final worm makes the same total mechanical reduction ratio of 705:1. The DC perm-mag based EQ5/LXD75, etc. will be very noisy during fastest slew speed. High motor RPM plus many gears inside the gear box make the mount noisy. This CN post showed the info.

There is a difference on this one with EQ6/HEQ5's. The EQ5's mechanical part is outside the mount body thus sound suppresion effect is not as good as enclosed body style.

Clear Skies!

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