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Re: Polar Alignment Scope Bushings


May 12, 2002

 


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

#10145 May 12, 2002

I have a used G-11 and it's dawning on me that an o-ring or bushing

may be missing on my Polar Alignment scope. Can someone direct me to a

picture of a disassembled PAS or describe the part?



Thanks,

RB



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

#10146 May 12, 2002

Is it inhibiting how tight you can get your RA clutch? Mine has a

small copper (?) wire spring washer between the lock ring and the lip

around the scope. If the spring washer was a little larger, or I

replace it with a rubber o-ring the finder won't move in so far that

it interferes with the clutch.



Sorry - no pix. Does this help?



Randy

--- In Losmandy_users@y..., "rdburns2002" rd-burns@t...> wrote:

> I have a used G-11 and it's dawning on me that an o-ring or bushing

> may be missing on my Polar Alignment scope. Can someone direct me

to a

> picture of a disassembled PAS or describe the part?

>

> Thanks,

> RB



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

#10147 May 12, 2002

--- In Losmandy_users@y..., "rdburns2002" rd-burns@t...> wrote: > I have a used G-11 and it's dawning on me that an o-ring or bushing

> may be missing on my Polar Alignment scope. Can someone direct me

to a > picture of a disassembled PAS or describe the part?

>

> Thanks,

> RB



Greetings Robert...



Take your led cover screw off so you can take the hold down ring

off. There should be a spring washer between the hold down ring and

the flange on the polar scope.



You may also need a bushing that fits in front of the clutch knob.

If you had a DSC you get it as part of the kit. If the spring washer

doesn't take care of the problem, then bug Scott for the part. You

may be also able to get the bushing from Torrington...



Clear Skies,

Janice Kreidel



P.S. I know exactly what your problem is as my new PAS and G-11 had

neither spring washer or bushing.



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

#10149 May 13, 2002

Janice and Randy,

Thanks for the replies. There's neither spring washer nor o-ring.

Look's like I need to contact Scott or find a o-ring at the local

hardware store. How thick should the o-ring be?



Robert









--- In Losmandy_users@y..., "janicekreidel" janicekreidel@e...>

wrote: > --- In Losmandy_users@y..., "rdburns2002" rd-burns@t...> wrote:

> > I have a used G-11 and it's dawning on me that an o-ring or

bushing > > may be missing on my Polar Alignment scope. Can someone direct me

> to a

> > picture of a disassembled PAS or describe the part?

> >

> > Thanks,

> > RB

>

> Greetings Robert...

>

> Take your led cover screw off so you can take the hold down ring

> off. There should be a spring washer between the hold down ring and

> the flange on the polar scope.

>

> You may also need a bushing that fits in front of the clutch knob.

> If you had a DSC you get it as part of the kit. If the spring

washer > doesn't take care of the problem, then bug Scott for the part. You

> may be also able to get the bushing from Torrington...

>

> Clear Skies,

> Janice Kreidel

>

> P.S. I know exactly what your problem is as my new PAS and G-11 had

> neither spring washer or bushing.



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

#10153 May 13, 2002

--- In Losmandy_users@y..., "rdburns2002" rd-burns@t...> wrote: > Janice and Randy,

> Thanks for the replies. There's neither spring washer nor o-ring.

> Look's like I need to contact Scott or find a o-ring at the local

> hardware store. How thick should the o-ring be?

>

> Robert



Please be aware that there was (still is?) an manufacturing problem

with the p.a. scopes. The silver lockring where the scope tube joins

the rear assembly was manufactured with too large an outer diameter.

As a result, -if- you install the DSCs, it can hit the RA shaft

housing, which will cause the RA shaft to bind if you tighten the

clutch. (It only happens with the DSCs, AFAIK, because this puts the

PA scope further into the tube.)



I discussed this problem with Scott a few years ago, and there are

several solutions:



1) Replace the lockring with something that has a smaller O.D.

2) File down the lockring so that it has a smaller O.D.

3) Insert enough washers or other bushings to provide adequate

clearance (not sure if this will work with the DSCs)

4) Replace the p.a. scope?



The washers and bushings that go between the clutch knob and the p.a.

scope, IIRC, are only there so you can continue to rotate the scope

even with the clutch tightened down. If you RA shaft is binding, it

is not because these are missing, it is likely because you are

experiencing the problem described above.



Cheers,

Paul Sterngold



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

#10156 May 13, 2002

not very thick, perhaps 1/16".. I would just check for a loosely fitting O-ring

at a hardware store.. or even make it yourself with a piece of #20 wire. You

dont want to lock the polar scope in, you still need to rotate it to align all

the stars.



"rdburns2002" rd-burns@...> wrote:

>Janice and Randy,

>Thanks for the replies. There's neither spring washer nor o-ring.

>Look's like I need to contact Scott or find a o-ring at the local

>hardware store. How thick should the o-ring be?

>

>Robert

>



Herm

Astropics home.att.net/~hermperez







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

#10162 May 13, 2002

Thanks all for the help. I found a 1/16 o-ring and tried it out this

evening. I don't know if the o-ring made all the difference or if I

just lucked out. After polar aligning with the scope, I set up to

drift align with a CCD method -- and it looked like I was right on

without any further adjustment. It's a work day tomorrow, but I took a

bunch of 60 sec integrations on M51 and got round stars. I'm one

happy camper right now!



RB





--- In Losmandy_users@y..., Herm hermperez@w...> wrote:

> not very thick, perhaps 1/16".. I would just check for a loosely

fitting O-ring

> at a hardware store.. or even make it yourself with a piece of #20

wire. You

> dont want to lock the polar scope in, you still need to rotate it to

align all

> the stars.

>

> "rdburns2002" rd-burns@t...> wrote:

>

> >Janice and Randy,

> >Thanks for the replies. There's neither spring washer nor o-ring.

> >Look's like I need to contact Scott or find a o-ring at the local

> >hardware store. How thick should the o-ring be?

> >

> >Robert

> >

>

> Herm

> Astropics home.att.net/~hermperez



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

#10163 May 13, 2002

Paul,

The silver (white metal?) lock ring was missing, too. I'm considering

a fifth solution; a miniscule drop of locktight on the threads, then

focusing it before the locktight dries. What do ya' think.



By the way, an o-ring seems to have solved the bushing problem. See my

other post.



thanks for your input,

RB

--- In Losmandy_users@y..., "psterngold" psterngold@y...> wrote:

> --- In Losmandy_users@y..., "rdburns2002" rd-burns@t...> wrote:

> > Janice and Randy,

> > Thanks for the replies. There's neither spring washer nor o-ring.

> > Look's like I need to contact Scott or find a o-ring at the local

> > hardware store. How thick should the o-ring be?

> >

> > Robert

>

> Please be aware that there was (still is?) an manufacturing problem

> with the p.a. scopes. The silver lockring where the scope tube joins

> the rear assembly was manufactured with too large an outer diameter.

> As a result, -if- you install the DSCs, it can hit the RA shaft

> housing, which will cause the RA shaft to bind if you tighten the

> clutch. (It only happens with the DSCs, AFAIK, because this puts the

> PA scope further into the tube.)

>

> I discussed this problem with Scott a few years ago, and there are

> several solutions:

>

> 1) Replace the lockring with something that has a smaller O.D.

> 2) File down the lockring so that it has a smaller O.D.

> 3) Insert enough washers or other bushings to provide adequate

> clearance (not sure if this will work with the DSCs)

> 4) Replace the p.a. scope?

>

> The washers and bushings that go between the clutch knob and the

p.a.

> scope, IIRC, are only there so you can continue to rotate the scope

> even with the clutch tightened down. If you RA shaft is binding, it

> is not because these are missing, it is likely because you are

> experiencing the problem described above.

>

> Cheers,

> Paul Sterngold



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

#10164 May 13, 2002

--- In Losmandy_users@y..., "rdburns2002" rd-burns@t...> wrote: > Paul,

> The silver (white metal?) lock ring was missing, too. I'm

considering > a fifth solution; a miniscule drop of locktight on the threads,

then > focusing it before the locktight dries. What do ya' think.

>

> By the way, an o-ring seems to have solved the bushing problem. See

my > other post.

>

> thanks for your input,

> RB



Sounds like a good solution to me, RB. I can't imagine that the scope

is going to turn much anyways on those threads, it's not like there's

a lot of vibration in there. g>



Cheers,

Paul Sterngold



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

#10165 May 14, 2002

This is from a non-optometrist so disregard if it does not apply.



It seems to me that eye focus can change from day to day and, of course,

there is a change if someone is at the scope who wears glasses. Locking

the focus may preclude others from viewing through the polar scope even if

it is ok for you.



Mike



At 05:25 AM 5/14/2002 +0000, you wrote: >Paul,

>The silver (white metal?) lock ring was missing, too. I'm considering

>a fifth solution; a miniscule drop of locktight on the threads, then

>focusing it before the locktight dries. What do ya' think.

>

>By the way, an o-ring seems to have solved the bushing problem. See my

>other post.

>

>thanks for your input,

>RB

>

>--- In Losmandy_users@y..., "psterngold" psterngold@y...> wrote:

> > --- In Losmandy_users@y..., "rdburns2002" rd-burns@t...> wrote:

> > > Janice and Randy,

> > > Thanks for the replies. There's neither spring washer nor o-ring.

> > > Look's like I need to contact Scott or find a o-ring at the local

> > > hardware store. How thick should the o-ring be?

> > >

> > > Robert

> >

> > Please be aware that there was (still is?) an manufacturing problem

> > with the p.a. scopes. The silver lockring where the scope tube joins

> > the rear assembly was manufactured with too large an outer diameter.

> > As a result, -if- you install the DSCs, it can hit the RA shaft

> > housing, which will cause the RA shaft to bind if you tighten the

> > clutch. (It only happens with the DSCs, AFAIK, because this puts the

> > PA scope further into the tube.)

> >

> > I discussed this problem with Scott a few years ago, and there are

> > several solutions:

> >

> > 1) Replace the lockring with something that has a smaller O.D.

> > 2) File down the lockring so that it has a smaller O.D.

> > 3) Insert enough washers or other bushings to provide adequate

> > clearance (not sure if this will work with the DSCs)

> > 4) Replace the p.a. scope?

> >

> > The washers and bushings that go between the clutch knob and the

>p.a.

> > scope, IIRC, are only there so you can continue to rotate the scope

> > even with the clutch tightened down. If you RA shaft is binding, it

> > is not because these are missing, it is likely because you are

> > experiencing the problem described above.

> >

> > Cheers,

> > Paul Sterngold

>

>

>

>To unsubscribe from this group, send an email to:

>Losmandy_users-unsubscribe@egroups.com

>

>

>

>Your use of Yahoo! Groups is subject to docs.yahoo.com/info/terms/







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

#10168 May 14, 2002

Thread lock isn't permanent (at least it's not if you pick the right

one), so if you sell the scope, someone else can adjust it to her

eyesight. Otherwise, it's not an item that you change that much. In

fact, it doesn't require precision focus, and the eye can accomodate

anyways.



Cheers,

Paul Sterngold

--- In Losmandy_users@y..., Michael Rudolph mrudolph@t...> wrote:

> This is from a non-optometrist so disregard if it does not apply.

>

> It seems to me that eye focus can change from day to day and, of

course,

> there is a change if someone is at the scope who wears glasses.

Locking

> the focus may preclude others from viewing through the polar scope

even if

> it is ok for you.

>

> Mike

>

> At 05:25 AM 5/14/2002 +0000, you wrote:

> >Paul,

> >The silver (white metal?) lock ring was missing, too. I'm

considering

> >a fifth solution; a miniscule drop of locktight on the threads,

then

> >focusing it before the locktight dries. What do ya' think.

> >

> >By the way, an o-ring seems to have solved the bushing problem.

See my

> >other post.

> >

> >thanks for your input,

> >RB

> >

> >--- In Losmandy_users@y..., "psterngold" psterngold@y...> wrote:

> > > --- In Losmandy_users@y..., "rdburns2002" rd-burns@t...> wrote:

> > > > Janice and Randy,

> > > > Thanks for the replies. There's neither spring washer nor o-

ring.

> > > > Look's like I need to contact Scott or find a o-ring at the

local

> > > > hardware store. How thick should the o-ring be?

> > > >

> > > > Robert

> > >

> > > Please be aware that there was (still is?) an manufacturing

problem

> > > with the p.a. scopes. The silver lockring where the scope tube

joins

> > > the rear assembly was manufactured with too large an outer

diameter.

> > > As a result, -if- you install the DSCs, it can hit the RA shaft

> > > housing, which will cause the RA shaft to bind if you tighten

the

> > > clutch. (It only happens with the DSCs, AFAIK, because this

puts the

> > > PA scope further into the tube.)

> > >

> > > I discussed this problem with Scott a few years ago, and there

are

> > > several solutions:

> > >

> > > 1) Replace the lockring with something that has a smaller O.D.

> > > 2) File down the lockring so that it has a smaller O.D.

> > > 3) Insert enough washers or other bushings to provide adequate

> > > clearance (not sure if this will work with the DSCs)

> > > 4) Replace the p.a. scope?

> > >

> > > The washers and bushings that go between the clutch knob and the

> >p.a.

> > > scope, IIRC, are only there so you can continue to rotate the

scope

> > > even with the clutch tightened down. If you RA shaft is

binding, it

> > > is not because these are missing, it is likely because you are

> > > experiencing the problem described above.

> > >

> > > Cheers,

> > > Paul Sterngold

> >

> >

> >

> >To unsubscribe from this group, send an email to:

> >Losmandy_users-unsubscribe@e...

> >

> >

> >

> >Your use of Yahoo! Groups is subject to

docs.yahoo.com/info/terms/



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

#10888 Jul 9, 2002

Subject: Re: Polar alignment redux

>

> --- In Losmandy_users@y..., "gnowellsct" gnowell@n...> wrote:

> > I had a chance to work on my elaborate protocol for aligning the

> > mount and have come to a conclusion.

> >

> > It doesn't work the way it ought to. Moreover, the reason I've ben

> > having good results lately is because Ed Joganic sent me some

> > plastic

> > bushings that do a marvelous job of holding the polar scope steady

> > and getting it closer to its theoretical performance level.

> >

> > I'm not sure why. But if the math guys had figured out a way, there

> > wouldn't be these elaborate T-point systems designed to reduce all

> > the sources of error.

> >

> > I have a hunch that much of the problem lies in the nature of right

> > ascension. I suspect that the reason drift alignment works is

> > because drift alignment as a technique starts with the assumption

> > that you are workingon the celestial equator. That I think is key.

>

> Does this have to do with the refractive index being variable

> throughout the sky?

>

> The plastic washers sound like a winner, any chance of getting ahold

> of some?

>

>

> Tim

> > It is possible that two star gem alignment might work better if

> > objects on the equator are chosen, but I'm beginning to think there

> > is no easy solution here. Well actually the easy solution is Ed

> > Joganic's bushings. I've had pretty damn solid results with those.

> >

> > regards,

> > Greg Nowell

>

> Tim, I machined a set of nylon bushings to center my polar alignment

scope in the polar axis. The bushings are slid into the polar axis, spaced

and cemented there. I think Greg is using them somewhat differently however.

The tolerance is about.001". My polar axis bore is .938 I.D. and the scope

is .905 O.D. This leaves a wall thickness of only .0165 - tricky to machine

accurately as the nylon deforms as it is cut and then recoils a small amount

which is temperature dependant. They would only work in your mount if Scott

cut the polar axis bore to the same diameter and there is absolutely no run

out in the hole. He probably knows the answer to that. You could get a good

idea if it would work in your mount by measuring the bore (dial caliper

would be ideal) and run out (a dial guage). My run out is unmeasureably

small. Scott is a incredible machinest. I'll try to post a few pictures of

how it all goes together within the new few days. Ed Joganic >

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

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

>

>

>

> Your use of Yahoo! Groups is subject to docs.yahoo.com/info/terms/

>

>







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

#10893 Jul 10, 2002

--- In Losmandy_users@y..., "Ed Joganic" astron1@m...> wrote:

> Tim, I machined a set of nylon bushings to center my polar

> alignment scope in the polar axis. The bushings are slid into the

> polar axis, spaced and cemented there. I think Greg is using them

> somewhat differently however. The tolerance is about.001". My polar

> axis bore is .938 I.D. and the scope is .905 O.D. This leaves a wall

> thickness of only .0165 - tricky to machine accurately as the nylon



Some trick machining indeed...

> deforms as it is cut and then recoils a small amount which is

> temperature dependant. They would only work in your mount if Scott

> cut the polar axis bore to the same diameter and there is absolutely

> no run out in the hole. He probably knows the answer to that. You

> could get a good idea if it would work in your mount by measuring

> the bore (dial caliper would be ideal) and run out (a dial guage).

> My run out is unmeasureably small. Scott is a incredible machinest.

> I'll try to post a few pictures of how it all goes together within

> the new few days. Ed Joganic



Thanks for the explanation Ed. I'd be interested in your pictures. I

did something similar, I think. I wrapped the PA scope in plumbers

teflon tape to build up the area where it contacts the bore in the

mount. It seems like this work well, the scope doesn't have any side

to side motion and it still rotates easily. But a machined bushing

would be better. Thanks for the information.





Tim

> >

> >

--------------- > >

--------------- > >

> >

> >

> > Your use of Yahoo! Groups is subject to

docs.yahoo.com/info/terms/ > >

> >



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