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Initial Alignment: Help Getting on the Celestial Pole

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#1 knightskye

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Posted 05 September 2016 - 09:23 AM

Meade's initial (before taking the GPS fix) 1-star polar alignment procedure has you place the scope in the "home" position and on the Celestial Pole -- which, of course, is some distance from Polaris.  In fact, while looking at Polaris through my LX200 -- through my lowest-magnification eyepiece (40mm) -- the celestial pole is not even within the field of view.  This degrades my search for the pole into a time-consuming game of hide-and-seek -- and usually leaves me with awful pointing accuracy when I ultimately fail to initialize the scope on the pole.  

 

Night after, night I watch owners of German EQ mounts peer through their polar alignment scopes -- specifically designed to get them on the celestial pole -- and tell myself . . . CERTAINLY their must be something out there to make this task easier on the LX200.  And of course, I search the Meade website and find . . . nothing.  It would seem to me that a sufficiently low-magnification eyepiece, with correct reticle markings would be all that would be required here, (as opposed to a dedicated polar alignment scope) because the LX200 tube is already ON the fork-mount's optical axis. (correct?)

 

Is anyone aware of such an eyepiece -- or some other product -- that could take the guess-work out of quickly/reliably getting on the celestial pole?   



#2 MistrBadgr

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Posted 05 September 2016 - 02:13 PM

I have not used an AutoStar II system, but am familiar with AutoStar I and AutoStar III. 

 

With AutoStar i, placing the scope level and pointing it North is just an approximate positioning that needs to be good enough to get the guide stars into the field of view. When the observer makes the position corrections manually, the errors are taken into account in the code. 

 

With AutoStar III on the LS 8 that I had, the scope figured out what level and North were, along with any tip or tilt in the level of the mount.  With its GPS fix, it would come up with location and time.  It would then go out, find the stars, image them with the little camera, make a correction, then image them again to make sure they were completely on target.

 

I suspect that your scope is somewhere between and that the initial orientation in relation to Polaris needs to be relatively close, but the scope will make up for the error when a star is centered and the GPS does its thing. 

 

Polaris itself is not exactly on the pole itself, but is close enough to use for anything except for very precise imaging.  If you really want to get it on the money, consider using a well aligned finder.  There are also eyepieces with cross-hairs in them, both illuminated and non-illuminated.  Meade sells a 9 mm Plossle and a 12 mm MA.  Both are illuminated, if you want to turn on the LED.  The 12 mm MA lists for $60 on the Meade site and the 9 mm Plossl for $89.

 

Hope this helps,

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#3 Fivel

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Posted 05 September 2016 - 02:56 PM

Hello nightskye. I have a wedge mounted LX200 with an Autostar II.

For initial alignment the home position depends on wether you are also wedge mounted or simply Alt/Az.

For Alt/Az the home is as Bill mentioned, level and pointed close to North. Once the GPS gets a fix it will then give you the alignment menu.You have the option of Easy, One Star or Two Star.

For wedge mounted, it will get the GPS fix then you will do a One Star alignment (one in addition to Polaris.

As also mentioned, for long exposure imaging you will need to perform an accurate polar alignment by whatever method(s) you are comfortable with, such as two star DRIFT alignment, (not the initial GOTO two star align), Iterative (between Polaris and another star) or by software assistance with polar alignment applications under computer control. 

 

Best of luck and dark skies

 

Fivel



#4 Mark Sibole

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Posted 05 September 2016 - 07:03 PM

What are you trying to accomplish?Imaging alignment or casual viewing?I can supply a lengthy write up and a how to but i need to know what flavor you are going for.

When I find out then ill take the time to make you a nice write up.

 

Regards

 

Mark


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MTSO Observatory
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#5 Mark Sibole

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Posted 05 September 2016 - 07:04 PM

PS  alt az or equatorial mount


Mark Sibole
MTSO Observatory
Fife Lake, Mi.

http://astronomy.qteaser.com

#6 Mark Sibole

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Posted 05 September 2016 - 07:06 PM

Meade's initial (before taking the GPS fix) 1-star polar alignment procedure has you place the scope in the "home" position and on the Celestial Pole -- which, of course, is some distance from Polaris.  In fact, while looking at Polaris through my LX200 -- through my lowest-magnification eyepiece (40mm) -- the celestial pole is not even within the field of view.  This degrades my search for the pole into a time-consuming game of hide-and-seek -- and usually leaves me with awful pointing accuracy when I ultimately fail to initialize the scope on the pole.  

 

Night after, night I watch owners of German EQ mounts peer through their polar alignment scopes -- specifically designed to get them on the celestial pole -- and tell myself . . . CERTAINLY their must be something out there to make this task easier on the LX200.  And of course, I search the Meade website and find . . . nothing.  It would seem to me that a sufficiently low-magnification eyepiece, with correct reticle markings would be all that would be required here, (as opposed to a dedicated polar alignment scope) because the LX200 tube is already ON the fork-mount's optical axis. (correct?)

 

Is anyone aware of such an eyepiece -- or some other product -- that could take the guess-work out of quickly/reliably getting on the celestial pole?   

your 8x10 finder scope is all you need and ill add more when i get more info from my previous post


Mark Sibole
MTSO Observatory
Fife Lake, Mi.

http://astronomy.qteaser.com

#7 SBacon

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Posted 06 September 2016 - 12:43 PM

Hey Knightskye,

 

Here's my two cents . . .

 

I set Stellarium at the time I'm going to align and then to a 5 degree FOV.  Turn on the equatorial grid, and go to the Pole Star. There you will see how far Polaris is from the North Celestial Pole. (You can turn on the Telrad sight at this point so that everything can be centered on your screen.) Now switch to equatorial mount. If you are using the 8x50 finder scope this is the view you want to adjust your wedge to. Sure, its just a guess, but there have been more times than not that I have been close enough for pretty accurate pointing and tracking.  The other option is as you mentioned, a polar scope. I am thinking of replacing my finder scope with an illuminated polar scope because once I am aligned, I never use it.

 

Steve



#8 Bob Hess

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Posted 17 March 2017 - 10:16 AM

Steve,

I like your approach. Are you saying that the 5 degree FOV is what you get with an 9X50 finder? Does Stellarium show the NCP? Realizing the finder is giving you an upside down, backward view then you would move the wedge accordingly and it should get you pretty close.

 

Bob


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#9 SBacon

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Posted 20 March 2017 - 12:40 PM

Hi Bob,

 

Yes. A 5 deg FOV is what you get with the 8x50 on my LX90. Stellarium does show the NCP when you turn on the equatorial grid. and you are absolutely right about the backward view.

 

Now, since I posted this, I bought and installed an illuminated polar scope from Orion and an illuminated reticle eyepiece from Meade. By using a polar alignment app on the 'ol trusty smartphone, I am able to get an alignment that puts the target in the FOV every time! As a result, I am able to get more pics without star trails.  I am hoping once I learn to use the auto guider this Spring to get even better results.

 

Here's a couple of pics of my set up with the polar scope.

 

Hope this helps.

 

Steve

Attached Thumbnails

  • Orion PS 6 lbl.jpg
  • Orion PS 3.jpg
  • Orion PS 4.jpg
  • Orion Illuminated Polar Scope.JPG


#10 Mark Sibole

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Posted 26 March 2017 - 06:23 PM

Any standard 8x50 finder will work.I always used the 8x50 finder for alignment =and i was even close enough to image with no drift autoguiding


Mark Sibole
MTSO Observatory
Fife Lake, Mi.

http://astronomy.qteaser.com





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