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Re: PE help part ii


Jan 28, 2006

 


----------------------------

#28656 Jan 28, 2006

ok i went back to the drawing board

and got 2-3 turns of pec data

before and after manual training:



whwastro.homestead.com/files/temp/PEC_2006_01_26--6_sec_data.xls



by my calculations (correcting for drift) i get:

PE

st dev.13.22381502

max.31.26898493

min.-35.07159097

range.66.34057591



after a training run i get:

PE

std dev.6.600244264

max.16.78456794

min.-20.37727237

range.37.16184031





as suggested i collected data at 6 sec intervals

unfortunately clouds passed thru and messed with my first PE run

so i went longer.

then i did a single session of manual PE training

and measured PE again.



not sure why it drifts off so much with the PEC active.



i didn't drift align

rather set up the scope with the polar scope and aligned on 10 stars

then did a polar axis correction.

looks like there's some drift in my data

so i've attempted to correct it by doing a least squares fit

and subtracting the drift.



i'm a bit new to this sort of evaluation

is the a reasonable PE?

anything i can do to improve it?



the mount was bought in 3/02 and rarely used

i purchased it used last summer

and am just getting going with it



any help would be appreciated



-bill warden



----------------------------

#28661 Jan 29, 2006

--- In Losmandy_users@yahoogroups.com, "Rainer" rsbfoto@r...> wrote: >

> Hi Bill,

>

> That is a better info now.

>

> Well +-30" arcseconds is too much from my point of view.

>

> Have you checked the alignment of the reduction gear output shaft in

> relatio to the worm ? You can do this by taking a look at the Oldham

> coupler and see if the pins do protrude to much out of the plastic

> insert.

>

> Another thing I do not like is the nervousity of your PE. It jumps

> too much up and down. Looks like if the ballbearings are too rough.

>

> The big drift in the corrected PE with PEC is normal. That is a know

> problem in the Gemini. I guess you have Level3 v 1.13 or less in your

> mount.

>

> I would recommend to first check the mechanical side of your mount

> before doing more PEC trials.

>



thanks for your reply

bummer though

1. i just got the gemini system back from a software upgrade *to*

level 3 v1.13*



2. an excel spread sheet i can handle,

but i have no idea what the "Oldham coupler" is

or how to safely access the bearings.

i can't find any appropriate figures in the manual.

are there any figures or guides for this?



----------------------------

#28662 Jan 30, 2006

Hi Bill,



Take a look at this image



www.rainerehlert.com/astro/worm/GEAR-MESH-ADJUST.jpg



Maybe it helps. If you have problems with dismantling a mount can you

get help from some friend so you feel comfortable doing it ? Maybe a

machine shop could help you.



There is nothing that can be broken, do not worry. The only thing

that you will have to do quite consciously is the adjustment of the

worm/gear mesh but moving step by step inwards will bring you to a

result.



The ballbearings do sit in the little blocks. The bearing of the left

block can be taken out easily but the right one is a little bit more

difficult. Having the block in the hand you can test the smothness of

the ball bearings by turining the inner ring with a finger and then

you will feel how it runs.



best regards Rainer



>

> --- In Losmandy_users@yahoogroups.com, "Rainer" rsbfoto@r...>

wrote: > >

> > Hi Bill,

> >

> > That is a better info now.

> >

> > Well +-30" arcseconds is too much from my point of view.

> >

> > Have you checked the alignment of the reduction gear output shaft

in > > relatio to the worm ? You can do this by taking a look at the

Oldham > > coupler and see if the pins do protrude to much out of the

plastic > > insert.

> >

> > Another thing I do not like is the nervousity of your PE. It

jumps > > too much up and down. Looks like if the ballbearings are too

rough. > >

> > The big drift in the corrected PE with PEC is normal. That is a

know > > problem in the Gemini. I guess you have Level3 v 1.13 or less in

your > > mount.

> >

> > I would recommend to first check the mechanical side of your

mount > > before doing more PEC trials.

> >

>

> thanks for your reply

> bummer though

> 1. i just got the gemini system back from a software upgrade *to*

> level 3 v1.13*

>

> 2. an excel spread sheet i can handle,

> but i have no idea what the "Oldham coupler" is

> or how to safely access the bearings.

> i can't find any appropriate figures in the manual.

> are there any figures or guides for this?

>



----------------------------

#28663 Jan 30, 2006

Hola Rainer:



Soy Juanjo , te respond. a tu tultimo mensaje antes de Navidad no se si lo leiste. He visto este mensaje y me interesa que me expliques la distancia optima que tiene que tener los bloques para aproximar el tornillo. Tienes que tener en cuenta que yo cambi. las junatas Holdham por otras pero el efectoes el mismo.



saludos desde espa.a

juanjo





Rainer rsbfoto@...> escribi.:

Hi Bill,



That is a better info now.



Well +-30" arcseconds is too much from my point of view.



Have you checked the alignment of the reduction gear output shaft in

relatio to the worm ? You can do this by taking a look at the Oldham

coupler and see if the pins do protrude to much out of the plastic

insert.



Another thing I do not like is the nervousity of your PE. It jumps

too much up and down. Looks like if the ballbearings are too rough.



The big drift in the corrected PE with PEC is normal. That is a know

problem in the Gemini. I guess you have Level3 v 1.13 or less in your

mount.



I would recommend to first check the mechanical side of your mount

before doing more PEC trials.



An acceptable PE for a GM-8 should be around+-10" to max +-15"

arcseconds.



regards Rainer







>

> ok i went back to the drawing board

> and got 2-3 turns of pec data

> before and after manual training:

>

>

>

> by my calculations (correcting for drift) i get:

> PE

> st dev 13.22381502

> max 31.26898493

> min -35.07159097

> range 66.34057591

>

> after a training run i get:

> PE

> std dev 6.600244264

> max 16.78456794

> min -20.37727237

> range 37.16184031

>

>

> as suggested i collected data at 6 sec intervals

> unfortunately clouds passed thru and messed with my first PE run

> so i went longer.

> then i did a single session of manual PE training

> and measured PE again.

>

> not sure why it drifts off so much with the PEC active.

>

> i didn't drift align

> rather set up the scope with the polar scope and aligned on 10 stars

> then did a polar axis correction.

> looks like there's some drift in my data

> so i've attempted to correct it by doing a least squares fit

> and subtracting the drift.

>

> i'm a bit new to this sort of evaluation

> is the a reasonable PE?

> anything i can do to improve it?

>

> the mount was bought in 3/02 and rarely used

> i purchased it used last summer

> and am just getting going with it

>

> any help would be appreciated

>

> -bill warden

>













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----------------------------

#28665 Jan 30, 2006

Hola Juanjo,



I just sent you a private e-mail.



regards Rainer



>

> Hola Rainer:

>

> Soy Juanjo , te respond. a tu tultimo mensaje antes de Navidad no

se si lo leiste. He visto este mensaje y me interesa que me expliques

la distancia optima que tiene que tener los bloques para aproximar el

tornillo. Tienes que tener en cuenta que yo cambi. las junatas Holdham

por otras pero el efectoes el mismo. >

> saludos desde espa.a

> juanjo



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