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Focusing the ETX90


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#1 RickScofield

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Posted 11 June 2014 - 03:57 PM

I am having difficulty focusing my ETX 90 when using the higher powered eyepieces so I started to look around on the internet for focusers for the ETX90 that would help me get more granular with the adjustment on the scope.

After exchanging a couple of e-mails with the folks at JMI, they were convinced that their MOTOFOCUS part # MFETX would work for my ETX90 so I ordered one. I received it and attempted to install it but quickly discovered a major issue with the install and to make a long story sort, the current configuration for this device is not compatible with the current MEADE ETX90 MAK Portable Observatory (3514-04-20). It’s designed to fit the older versions. So the MOTOFOCUS is on its way back to JMI, they did indicated that they may in the future build a focuser for the new ETX90 but need one so they can design and fabricate it. In the mean time I am still looking for a solution to my focusing problem. Does anyone have a solution?   

 



#2 MistrBadgr

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Posted 11 June 2014 - 06:48 PM

Rick,

 

Contact Bill Vorce at www.telescope-warehouse.com.  I don't know if he still has any, but he had some little motorized focuser devices for the  ETX.  I thought about getting one and trying to adapt it to my LS 8, but decided it would probably not be strong enough for my scope.  I have no idea if he has any left or if they will fit your particular version.  But, it is probably worth a check.  Bill has both an email address and a phone number on his website.

 

Bill Steen


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#3 Mark Sibole

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Posted 11 June 2014 - 07:40 PM

Focusing the ETX takes an easy hand.

I did have one of the jmi focusers and found it a bit clunky.

What most people do is make a larger diameter ring and drill the center out of it and slid it over the original focuser.It gives you a bigger knob and you can fine tune the focus a lot easier.

Also remember you can only use so much magnification before you catch up with seeing conditions and things blur up.

Some nights you can get away with a 9 mm EP with no problems but if the seeing is bad (unstable air currents in the jet stream) you will have to drop down to a lower power EP.


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#4 RickScofield

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Posted 12 June 2014 - 02:31 PM

Bill, Mark,

Thank you both for the advice, I'll see what the Telescope Warehouse may have and also make a rubber knob to fit over the factory one as you suggested Mark. It's worth a try. I'll continue to try to perfect the focus adjustment. I think as time goes on I may get better at it. I do relaize that you can't always use a 9 or 4.5 mm eyepiece.         

Again thank you both.



#5 RickScofield

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Posted 12 June 2014 - 08:10 PM

Bill and Mark,

I e-mailed the Telescope Warehouse and William responded very quickly saying that the focuser he had would probably not work on my ETX 90 but that it was for the older version of the ETX90. So before I setup for tonight I dug through my stuff in the garage and found a couple of O-rings that fit over the focus knob. They made it a little bigger around but also allows me to adjust it finer because of the the friction I can generate with my fingers and it just feels better. Believe it or not that helped allot. I was able to bear down on Saturn with the 9mm and wow what a great view. I even had my wife looking at it. The only minor problem I am having is tracking. Objects don’t stay in the center of the eyepiece. My tracking speed is set to SIDEREAL. Is there a Function that can be used after the object slewed and manually centered manually to adjust the tracking or am I missing something else? Should I TRAIN my drives?

 

It’s so good to have my telescope back or my new one. I can’t tell you guys how much I enjoy gazing at the sky. The first thing I do in the mornings is check the weather for the evening to see if going to be clear and if it is, I start to plan my nights viewing. I think I am going to start planning with more detail for my nights viewing and start keeping a log. Will see how that goes.

Thank you for your help and guidance.              



#6 Mark Sibole

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Posted 13 June 2014 - 04:07 AM

sidereal time is the one you want  the only other option is for lunar.If your not tracking well its more than likely you dont have a great polar alignment.Make sure your scope is level and you get a good polar alignment.The only other thing is it could be weak batterys.


Mark Sibole
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http://astronomy.qteaser.com

#7 MistrBadgr

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Posted 13 June 2014 - 05:04 AM

Rick,

 

The only couple of things I can think of, besides what Mark told you, is to train the drives on the scope and entering in the position of each object you view.  

 

There should be a routine in setup menu for traing the drives.  Doing that just lets the scope know how much backlash there is in each of the drive trains.

 

The other thing that I normally do when I get an object truly centered is to push the enter button in for a bout three seconds, then release.  The scope beeps.  Then I push the botton again and release.  The scope beeps again.  The first long button press tells the scope that the object you just had it go to is centered. The second button press tells the scope to enter that information into the alignment algorithm.

 

Bill Steen


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#8 RickScofield

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Posted 13 June 2014 - 12:38 PM

Mark, Bill, I am using SIDREAL for tracking speed and its not weak batteries as I was using #546 AC Adapter. I did just train my drives both AZ and ALT so I'll see if that helps tonight. I will also try the SYNC function with the ENTER key after it completes its slew, BEEPS and I adjust.   

 

Thank you !         



#9 RickScofield

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Posted 16 June 2014 - 06:27 PM

Gentelman,

I am wondering why MEADE lists the #1244 Electric Focuser in the ETX User Manual,(Page 19) when in fact it will not work on the current version of the ETX 90MAK? I understand that they no longer offer the#1244 Focuser so why do they continue to list it in the USERS MANUAL under the OPTIONAL ACCESSORIES section starting on page 17?

More importantly, the other issue that concerns me here is, what other items or procedures in the User Manual no longer apply to the current version of the ETX 90 or what has been added that’s not included in this version of the USERS MANUAL?            



#10 MistrBadgr

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Posted 17 June 2014 - 04:00 AM

Hi Rick,

 

I am fairly sure that updating that instruction manual got lost in the shuffle when the new version of the ETX 90 came out.

 

Not having an ETX inhibits my confidence in what I am about to say, but I believe all of the main procedures are the same.  The handset, which has all the real controls in it, has not changed in a way that would affect the buttons you punch to get the scope to do something.  The handsets are the same for the ETX, DS, LT, and LX 90 series, I think.

 

Where there is a difference between the newer and older version of the ETX that would affect the operation as you would see it, it would most likely be with something like a non-optical assessory.

 

Bill Steen


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#11 RickScofield

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Posted 17 June 2014 - 07:06 AM

Bill,

Thank you for your response and I suspect you’re correct. It's all in the handset. I think MEADE could avoid some confusion by correcting the USERS MANUAL. I would also hope that MEADE would update the #1244 Focuser or introduce a new model for the new ETX 90MAK. That way folks wouldn’t have to look at aftermarket options. Thank you again.          



#12 RickScofield

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Posted 02 July 2014 - 01:25 PM

Mark, Bill,

I ended up getting a cane bottom cap made of rubber that fit over the focus knob and almost doubled the diameter of the focus knob. This has really helped me with controlling my focusing.

 

Thank you both for your help.



#13 MistrBadgr

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Posted 02 July 2014 - 02:38 PM

Hi Rick,

 

Glad to hear the focus issue is at least diminished.  Glad to be of help.

 

Bill Steen


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#14 Skyewatcher

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Posted 27 July 2014 - 10:55 AM

Rick, if you,re looking for a focusing device, then have a look at my electric focuser. It might help you with fine

adjustment.

You can find it on Ron Weasner's web site at http://www.weasner.c...x/techtips.html. It's under "add ons" ,

Meade ETX 125 PE Electric Focuser.

 

Regards,

 

Mike Shuter.

 

mike_shuter@sky.com

 



#15 RickScofield

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Posted 28 July 2014 - 06:28 AM

Mike,
Thank you for your response. If you would would you please e-mail me the details of your focuser , Rick.scofield@cox.net
Again Thank you.
Rick S.

#16 Atjous

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Posted 02 August 2014 - 02:04 PM

I made a simple focus aid by "modifying" a clothes pin so that it fits on the focussing knob, creating an ultra-cheap lever that will give you a nice, smooth, precise focus!
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#17 MistrBadgr

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Posted 02 August 2014 - 06:20 PM

Atjous,

 

Great idea, and welcome to the forum!

 

Bill Steen


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#18 RickScofield

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Posted 02 August 2014 - 08:27 PM

Wow what a great idea, I'll have to give that try. Thank you !  



#19 Atjous

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Posted 03 August 2014 - 02:12 AM

Atjous,
 
Great idea, and welcome to the forum!
 
Bill Steen


Thank you, Bill!
Considering the clothes pin: it takes a bit of tweaking and shaping, but the results so far have been astonishing for me: a dramatic reduction in shake and an enormous increase in precision. All that for $ 0.01.

Meade LX90 8" GPS | Meade ETX90 | Coronado PST | Celestron C70


#20 MistrBadgr

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Posted 03 August 2014 - 11:54 AM

I am thinking the same kind of thing would be useful on my LS 8.  It does not have the problems, or at least the exact same ones, as the ETX, but things can wiggle around pretty good at higher magnifications.  The light weight tripod, which is there for a good reason, it the issue.  Having a lever attached to the focus knob that can simply be pushed on one side or the other might just be what improves the situation.

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma




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