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Re: polar alignment scope accuracy questions.


May 23, 2006

 


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

#29874 May 23, 2006

Probably very dumb questions but will ask any way.



.



What is the easiest way to check the accuracy of my polar scope?



Can the reticule or the scope itself be realigned if its off?



Do most of you actually use the 2nd star, I guess Kochab (I have

never been able to see it) for polar alignment?



It amazes me how much the Polaris position moves in the reticule

when I rotate the polar scope?



.



I have never tried a drift alignment. I guess I could do one and

see if Polaris is in proper location of my polar scope?



.



Your patient help/advice will be appreciated.



.



Roger Zellmer, San Diego, CA



N 32, W 117



TV85, Celestron 8" SCT CF XLT



Losmandy G11 mount w/ side by side



Canon Rebel, Coronado PST



40mm solar scope



www.rogerzellmer.com/















[Non-text portions of this message have been removed]



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

#29875 May 23, 2006

You can adjust the polar alignment accuracy by using the screws on the

polar alignment viewfinder.

point it at a street light about a mile away

losen the RA axis and swivel it 180 degrees back and fourth.

at 0,90 and 180 degrees, be sure the crosshair is still dead center on

the street light while rotating RA, and it's aligned.



I use the second star. Alignment is very close after doing these two

steps.



I have not tried to drift align yet...



Hope this helps

Casey





--- In Losmandy_users@yahoogroups.com, "Roger Zellmer"

rogerzellmer@...> wrote: >

> Probably very dumb questions but will ask any way.

>

> .

>

> What is the easiest way to check the accuracy of my polar scope?

>

> Can the reticule or the scope itself be realigned if its off?

>

> Do most of you actually use the 2nd star, I guess Kochab (I have

> never been able to see it) for polar alignment?

>

> It amazes me how much the Polaris position moves in the reticule

> when I rotate the polar scope?

>

> .

>

> I have never tried a drift alignment. I guess I could do one and

> see if Polaris is in proper location of my polar scope?

>

> .

>

> Your patient help/advice will be appreciated.

>

> .

>

> Roger Zellmer, San Diego, CA

>

> N 32, W 117

>

> TV85, Celestron 8" SCT CF XLT

>

> Losmandy G11 mount w/ side by side

>

> Canon Rebel, Coronado PST

>

> 40mm solar scope

>

> www.rogerzellmer.com/

>

>

>

>

>

>

>

> [Non-text portions of this message have been removed]

>



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

#29879 May 23, 2006

Roger Zellmer wrote:

>What is the easiest way to check the accuracy of my polar scope?

>

>



Roger,



Drift align the mount to the desired accuracy then the polar scope will

indicate the error.

>Can the reticule or the scope itself be realigned if its off?

>

>



Yes

>Do most of you actually use the 2nd star, I guess Kochab (I have

>never been able to see it) for polar alignment?

>

>



It's tough from in town but in a darker site it's useable

>.

>

>I have never tried a drift alignment. I guess I could do one and

>see if Polaris is in proper location of my polar scope?

>

>



Ta Da! Exactly. A lot of people seem to be afraid of drift aligning and

will look for any reason not to do it. It's really quite simple and will

work even when the pole star(s) are not visible.





Regards



Bill





--



William R. Mattil.:.www.celestial-images.com



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

#29881 May 23, 2006

I may be wrong, but I think that you do not have to align your polar scope by

doing a precision alignment, then seeing if the reticle is pointing to the

right location. All you need to do is get the polar scope aligned with the

mount's RA axis. It is easiest to do this during the daytime. Simply point

the center of the reticle at an object and then spin the RA axis 180 degrees.

The object is likely to be out of the center now. Use the three tiny set

screws to adjust the reticle until whatever is centered stays that way as you

rotate the RA axis. (Be careful when you adjust those three little screws

because they apply pressure to the edges of the delicate reticle glass and can

easily crack it.)



BTW, drift alignment is easy and when I first did it, I thought it was fun and

interesting. But it is a time sink, especially if you do it every time you set

up.



Cheers,

Paul Sterngold



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

#29882 May 23, 2006

Paul,

Thanks for the response. Did yours require this adjustment?

Has anybody successfully adjusted this reticule?

.

Roger Zellmer, San Diego, CA

N 32, W 117

TV85, AS-GT mount

Canon Rebel, Coronado PST

40mm solar scope

www.rogerzellmer.com/

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

From: Losmandy_users@yahoogroups.com

[mailto:Losmandy_users@yahoogroups.com] On Behalf Of Paul

Sterngold

Sent: Tuesday, May 23, 2006 3:15 PM

To: Losmandy_users@yahoogroups.com

Subject: Re: [Losmandy_users] polar alignment scope accuracy

questions.



I may be wrong, but I think that you do not have to align your

polar scope by

doing a precision alignment, then seeing if the reticle is

pointing to the

right location.. All you need to do is get the polar scope

aligned with the

mount's RA axis.. It is easiest to do this during the daytime..

Simply point

the center of the reticle at an object and then spin the RA axis

180 degrees.

The object is likely to be out of the center now.. Use the three

tiny set

screws to adjust the reticle until whatever is centered stays

that way as you

rotate the RA axis.. (Be careful when you adjust those three

little screws

because they apply pressure to the edges of the delicate reticle

glass and can

easily crack it.)



BTW, drift alignment is easy and when I first did it, I thought

it was fun and

interesting.. But it is a time sink, especially if you do it

every time you set

up.



Cheers,

Paul Sterngold



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

#29883 May 23, 2006

--- In Losmandy_users@yahoogroups.com, "Roger Zellmer"



Hi Roger,

> Thanks for the response. Did yours require this adjustment?

> Has anybody successfully adjusted this reticule?



On my PA scopes (PAS) for the AP 900 and G-11 they both needed

alignment. This is not a surprise. For the G-11 I used the method

posted, that is, point the mount at a distant object (like it's the

pole star) and rotate the RA around in a circle while adjusting the

mount till the distant object is centered and then the reticule is

centered. One is supposed to be able to place the PAS in a V block,

rotate, and adjust the reticule that way. You can make these

adjustments in daylight.



The allen head screw is 0.035" or 0,9mm. The reticule i svery

delicate and will cost you about $65 if you break it. When using the

wrench I just torque sliding the wrench through my finger tips. Never

had a problem with breakage.



Accuracy is really impressive, in San Diego I am (was?) able to see

the three stars and if one interpolates the 2006 position of the stars

the result were good. I recall once I used the PAS then checked drift

alignment and the star tracked for 5 minutes perfectly. The PAS

nailed it.



There are some tricks to drift alignment it seems to me.





Tim



> .

> Roger Zellmer, San Diego, CA



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

#29886 May 24, 2006

--- Roger Zellmer rogerzellmer@...> wrote: > Thanks for the response. Did yours require this adjustment?

> Has anybody successfully adjusted this reticule?



Hi Roger,



I have not made this adjustment to my G11's polar scope, at least not yet. I

am working on other mount projects at the moment including upgrading my chip to

L4, then modeling my PE curve with PEMPro. Eventually, I will need to adjust

my PA scope.



I did adjust the PA scope in my Vixen GP-DX mount many years ago. It was easy

to do and improved the alignment accuracy. I recommend the procedure.



Cheers,

Paul Sterngold



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

#29888 May 24, 2006

Probably very dumb questions but will ask any way.

Not at all. This is so little documented, that it ought to be in a 'FAQ'

somewhere. :-)

Others have answered most parts, but I'll just add a 'caveat'. Remember

that the reticule itself, is a very thin piece of glass, and be _delicate_

when adjusting it. Make sure you slacken a screw before tightening another.

There have been some posts here in the past from people who have cracked

the reticule...

As for the movement of Polaris, when you realise that it is about 3/4

degree from the actual 'pole' (more than the diameter of the Moon), and how

big the Moon appears through even a finder scope, you will get an idea of

why the movement is large!.



Best Wishes







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

#29890 May 24, 2006

I tried to adjust mine once and busted the reticle. A $150 lesson

in "leave it alone."



Of more importance than the reticle adjustment IMHO is removing the

wobble by putting some electircal tape on the N or upper end of the

polar scope so it points in one place. If it turns out the PS is

not that accurate you can pretty much memorize where the 2nd star is

after you do a drift align.



I note that using Argo Navis, I measured my polar scope misalignment

one night as only 2 arc minutes in alt and 7 arc minutes in az,

which I consider an excellent result. That's on an "as is" polar

scope from the factory. YMMV.



regards

Greg N





--- In Losmandy_users@yahoogroups.com, "Tube Tim" potentate@...>

wrote: >

> >--- In Losmandy_users@yahoogroups.com, "Roger Zellmer"

>

> Hi Roger,

>

> > Thanks for the response. Did yours require this adjustment?

> > Has anybody successfully adjusted this reticule?

>

> On my PA scopes (PAS) for the AP 900 and G-11 they both needed

> alignment. This is not a surprise. For the G-11 I used the method

> posted, that is, point the mount at a distant object (like it's the

> pole star) and rotate the RA around in a circle while adjusting the

> mount till the distant object is centered and then the reticule is

> centered. One is supposed to be able to place the PAS in a V

block, > rotate, and adjust the reticule that way. You can make these

> adjustments in daylight.

>

> The allen head screw is 0.035" or 0,9mm. The reticule i svery

> delicate and will cost you about $65 if you break it. When using

the > wrench I just torque sliding the wrench through my finger tips.

Never > had a problem with breakage.

>

> Accuracy is really impressive, in San Diego I am (was?) able to see

> the three stars and if one interpolates the 2006 position of the

stars > the result were good. I recall once I used the PAS then checked

drift > alignment and the star tracked for 5 minutes perfectly. The PAS

> nailed it.

>

> There are some tricks to drift alignment it seems to me.

>

>

> Tim

>

>

> > .

> > Roger Zellmer, San Diego, CA

>



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