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RE: [Losmandy_users] Polar Alignment, Was: Re: New gadget?


Aug 2, 2008

 


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

#38639 Aug 2, 2008

Greg, 2 arc min PA is achievable with drift alignment...it just takes

a bit of time and patience. I would venture to guess that most

permanent setups are at least this well aligned. Remember also that

Gemini models for errors other than just PA error and can do a

reasonably good job of determining the true error with as few as 3 to

5 alignments. The more the alignment stars are added the better the

model gets (similar to TPoint). Once the model is stable Gemini's PAC

routine makes the mount adjustment a snap by offsetting a star at the

equator/meridian. There are some articles on polar alignment on my

website, if you are interested:

celestialwonders.com/articles/polaralignment



Frank Barrett

celestialwonders.com

--- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@...> wrote:

>

> even with drift alignment it seems to me it would be difficult to get

> more than to within 2 arc minutes of true N. Or am I just plain

wrong????

>

> thanks

> Greg N

>

>

> --- In Losmandy_users@yahoogroups.com, "Frank Barrett" frankb@> wrote:

> >

> > Jim,

> >

> > I agree with you, and I am consistently getting around 2 arc minute PA

> > with the Gemini PAC. But also keep in mind that declination drift is

> > more prominent around equatorial declinations, RA drift there is

> > negligible. So if you can correct declination you may be able to

> > image longer than the 5 to 10 minute design point mentioned on the

> > website.

> >

> > Frank Barrett

> > celestialwonders.com

> >

> > --- In Losmandy_users@yahoogroups.com, Jim Jones albiero@> wrote:

> > >

> > > If this pans out, I'm not sure why you would need to guide.

> > >

> > > Your PA will have to be right on. I believe that he so states

in his

> > > web site. But I would be willing to spend the time to get a spot

> on PA

> > > if this thing works as advertised.

> > >

> > > Some very innovative thinking here.

> > >

> > > Jim

> > >

> > > Frank Barrett wrote:

> > > > An interesting gadget to be sure. The stated correction is well

> below

> > > > my typical seeing! One thing to think about: it looks like

> > > > autoguiding is not possible since it uses the autoguide port.

What

> > > > about declination drift due to polar misalignment? I sent

Atilla an

> > > > email about this, but my knee jerk thinking is that you may be

> able to

> > > > independently guide out dec drift via the serial port and let

> the TDM

> > > > take care of the RA. Of course, price will play into the decision

> > > > process (as always).

> > > >

> > > > Frank Barrett

> > > > celestialwonders.com

> > > >

> > > > --- In Losmandy_users@yahoogroups.com, "wa1vta01452" tloebl@>

> wrote:

> > > >

> > > >> Came across this on the EQ6 group...

> > > >>

> > > >>

> > > >>

> > > >

> >

>

www.mda-telescoop.com/index.php?option=com_content&task=view&id=40&Itemid=61���=en

> > > >

> > > >

> > > >

> > > >

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

> > > >

> > > > Yahoo! Groups Links

> > > >

> > > >

> > > >

> > > >

> > > >

> > >

> >

>



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

#38640 Aug 2, 2008

Having just come back from Summer Star Party I got a chance to play with my

mount and PemPro. I found my mount to have roughly 12 arc seconds PE btw,

which I programmed out to around 3 arc seconds residual.







I played with Pempro's polar alignment feature and got my PA error down to

25 arc seconds in az and 0 in elevation. I did notice that Pempro tells you

to move azimuth the wrong way when using an SCT. I'm going to contact them

about that. The nice thing is that it only takes around 60 seconds to see

how far off you are on each measurement.







Tom P.







From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

On Behalf Of Frank Barrett

Sent: Saturday, August 02, 2008 10:38 AM

To: Losmandy_users@yahoogroups.com

Subject: [Losmandy_users] Polar Alignment, Was: Re: New gadget?







Greg, 2 arc min PA is achievable with drift alignment...it just takes

a bit of time and patience. I would venture to guess that most

permanent setups are at least this well aligned. Remember also that

Gemini models for errors other than just PA error and can do a

reasonably good job of determining the true error with as few as 3 to

5 alignments. The more the alignment stars are added the better the

model gets (similar to TPoint). Once the model is stable Gemini's PAC

routine makes the mount adjustment a snap by offsetting a star at the

equator/meridian. There are some articles on polar alignment on my

website, if you are interested:

celestialwonders.com/articles/polaralignment



Frank Barrett

celestialwonders.com



--- In Losmandy_users@yahoogroups.com

mailto:Losmandy_users%40yahoogroups.com> , "gnowellsct" tim71pos@...>

wrote: >

> even with drift alignment it seems to me it would be difficult to get

> more than to within 2 arc minutes of true N. Or am I just plain

wrong???? >

> thanks

> Greg N

>

>

> --- In Losmandy_users@yahoogroups.com

mailto:Losmandy_users%40yahoogroups.com> , "Frank Barrett" frankb@> wrote: > >

> > Jim,

> >

> > I agree with you, and I am consistently getting around 2 arc minute PA

> > with the Gemini PAC. But also keep in mind that declination drift is

> > more prominent around equatorial declinations, RA drift there is

> > negligible. So if you can correct declination you may be able to

> > image longer than the 5 to 10 minute design point mentioned on the

> > website.

> >

> > Frank Barrett

> > celestialwonders.com

> >

> > --- In Losmandy_users@yahoogroups.com

mailto:Losmandy_users%40yahoogroups.com> , Jim Jones albiero@> wrote: > > >

> > > If this pans out, I'm not sure why you would need to guide.

> > >

> > > Your PA will have to be right on. I believe that he so states

in his > > > web site. But I would be willing to spend the time to get a spot

> on PA

> > > if this thing works as advertised.

> > >

> > > Some very innovative thinking here.

> > >

> > > Jim

> > >

> > > Frank Barrett wrote:

> > > > An interesting gadget to be sure. The stated correction is well

> below

> > > > my typical seeing! One thing to think about: it looks like

> > > > autoguiding is not possible since it uses the autoguide port.

What > > > > about declination drift due to polar misalignment? I sent

Atilla an > > > > email about this, but my knee jerk thinking is that you may be

> able to

> > > > independently guide out dec drift via the serial port and let

> the TDM

> > > > take care of the RA. Of course, price will play into the decision

> > > > process (as always).

> > > >

> > > > Frank Barrett

> > > > celestialwonders.com

> > > >

> > > > --- In Losmandy_users@yahoogroups.com

mailto:Losmandy_users%40yahoogroups.com> , "wa1vta01452" tloebl@> > wrote:

> > > >

> > > >> Came across this on the EQ6 group...

> > > >>

> > > >>

> > > >>

> > > >

> >

>

www.mda-telescoop.com/index.php?option=com_content

www.mda-telescoop.com/index.php?option=com_content&task=view&id=40&I

temid=61���=en> &task=view&id=40&Itemid=61���=en > > > >

> > > >

> > > >

> > > >

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

> > > >

> > > > Yahoo! Groups Links

> > > >

> > > >

> > > >

> > > >

> > > >

> > >

> >

>











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