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ATM eq mount
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#1 Space99

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Posted 19 December 2018 - 12:04 AM

Gratings everyone bow.gif  hope you all have a lovely xmas and clear sky.... unless you want a white xmas   smile.gif

 

So, my question to the anyone who have an opinion about German Equatorial Mount design is:                        1-   polar-alignment  mechanism

                                                                                                                                                               2-   clutch design

                                                                                                                                                               3-   Worm-wheel location

 

1: Looking at Mr Byers wonderful EQ mounts ... most has a very simple, but effective polar alignment push-pull bolts for Alt and a push-screw for the Az for the pier.... I guess.

    Compare this to a AP or other EQ mount designed to be flexible re different locations, it is very 'robust' isn't it??

    Simplicity mean very stable?... so for my new (yet to be finished) EQ mount in a permanent Obs, not need to be 'fine' adjusted' all the time. Just get it right 'once' and lock the bolts.

    So instead make the mount overly complex, with more chance for flexing... just follow Mr Byers.... shaft angle set to desired Alt  and the bolts will adj +/- 5deg?       smile.gif   Opinion(s) ??

     http://www.edbyersco.../mountings.html

 

2: I have two of Mr Byers' Worm-gear for the project. RA 11" and the DEC 7" .... usual clutch. It is functional, but not practical for a quick balance adjustment (IMHO). Would a 'Capstan's-wheel' arrangement better?

    A little bit of machining on the hub will do it...

3: Most modern Worm-gears are located north of bearings, with overhang design to pass Meridian tracking. I guess to reduce torsion-flex on shaft. 

    My RA will be 3" OD .... DEC 2"   Mr Byers use the RA Worm-gear in mid-bearing.  I want overhung Dec to track pass Meridian. Should the Worm-wheel located north of bearings? Your opinion? 

 

Thank you all for any help,

Mick


Edited by Space99, 19 December 2018 - 01:08 AM.

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#2 Cali

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Posted 19 December 2018 - 03:20 AM

I have no opinion regarding the German Equatorial Mount design.

 

- Cal


Edited by Cali, 19 December 2018 - 03:24 AM.


#3 mark77

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Posted 19 December 2018 - 07:47 AM

Mick

 

I have a large GEM mount with 11" byers gears.  I also have several exta byers gears for future projects.

 

I think you are asking very good questions but I really dont follow what you are saying/asking.  Can you elaborate?

 

Mark



#4 Space99

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Posted 19 December 2018 - 07:22 PM

Mick

 

I have a large GEM mount with 11" byers gears.  I also have several exta byers gears for future projects.

 

I think you are asking very good questions but I really dont follow what you are saying/asking.  Can you elaborate?

 

Mark

Thanks Mark,

 

sorry about my not so good English.... and the spell check not always pick up my accent   frown.gif

Include two pic with call-outs to identify my questions. The majority of EQ mounts has a continuous alt and az adjustment, Byers has not. My question is, would this simple, but effective method improve stability over a system where

lots of point of flex because of the adjustment mechanism.

I emphasize this will be a permanent setup.

 

Hope this will clear up my earlier explanation   smile.gif

 

Mick   

Attached Thumbnails

  • Byers-1.jpg
  • Byers-2.jpg


#5 Space99

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Posted 19 December 2018 - 07:32 PM

Mark, just had a look your link to the dome obs project. Gorgeous!

Noticed the EQ mount you made has no 'continuous' adjustment for polar alignment. 

 

Are you happy with the choice of the location of the Worm gears south of the bearings?

And what bearings have you used?

 

Cheers,

Mick



#6 mark77

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Posted 19 December 2018 - 07:36 PM

Mick

 

I believe Byers mounts are set up to have a range of adjustment, the elevation adjustment I think is enough to cover most of the continental 48 states in the US.  The rest is done by the mount setting.

 

Of course getting rid of any of these will make some improvement.  Unless you are going to be loading the mount beyond its stated capacity I wouldnt worry about it to much. 

 

Having the fine tune adjustment is a really good thing to have. For fixed installations, polar alignment is not something you do once and forget about it.  Over time you make it better and better.  As you do longer and longer exposures you realize that you need to improve it a little.

 

The mount itself was modified long before I got it (it was built in the 70's I think) but thats what I have the 4 bolts for.  I can do my fine tuning of elevation with the nuts.  The mount has +/- 3 degrees of freedom in a slot on the base, that gives me enough for fine tuning the az.

 

Bottom line is Byers stuff is very well designed, and "IF IT ANIT BROKE, DONT FIX IT."

 

Mark


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#7 mark77

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Posted 19 December 2018 - 07:41 PM

Mark, just had a look your link to the dome obs project. Gorgeous!

Noticed the EQ mount you made has no 'continuous' adjustment for polar alignment. 

 

Are you happy with the choice of the location of the Worm gears south of the bearings?

And what bearings have you used?

 

Cheers,

Mick

 

The dome took me 3 years to build, averaging 20 to 30 hours a week.  The garage was built by a contractor in the first 2 months.

 

The mount is the way I got it which except for the bottom elevation part is as it was built.  Both shafts are 2 1/2 inch diameter, the DEC shaft is solid steel and weighs 60 pounds.  I think it can handle everything I am going to put on it.  I expect to have 500 pounds of scope on their.  a 14 inch that is on there now, a 16 inch newt and 2 William Optics refractors, one one each side.  All with cameras.

 

If I were building one from scratch, I would consider the middle of the road mount as you have but I dont really think that makes a difference.  The shaft bearings are whats important, are they smooth, true, no flexure, etc.

 

Mark

 

 

Mark


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