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Assistance with guiding LX200GPS using Meade Wedge


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#1 Codeman

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Posted 04 April 2017 - 06:53 PM

I am hoping someone can provide some information on how to do a precision alignment or drift alignment of my 10”-LX200GPS mounted on a Meade Wedge. 

I have a video on how to polar align which I can do.  I have reviewed many more online but not any about drift pertaining to a wedge.

 

Polar Align

 

I level the tripod using the bullseye bubble level integral with the Wedge and have checked it with other smaller levels I have.  I have even put on the scope’s base, between the forks, a T-level that can be used when the scope is on the wedge or in alt-az mounting.  Helps make sure all is level. 

 

 

You point the forks north and have the scope pointing north parallel with the forks.  Then center the polar star in the eyepiece using the manual knob controls and not the handset.  I do this prior to turning on the scope.  No problem.  I even use the Meade 9mm 1.25" Plossl Illuminated Reticle Eyepiece to center Polaris in the crosshairs. 

 

 

I turn the scope on and it does its first movement prior to starting setup.  When complete I unlock it and move the scope back to level with the T-level between the forks.  This puts the scope pointing north which it always did and the forks equal distance from the ground (assuming the ground was level) or projected level line from the base of the wedge that is level to the world.

 

Once the scope moves or turns 90-degrees you again use the manual controls to center Polaris in the eyepiece again.  However, I have noticed that many times I must get a wider field of view eyepiece to get Polaris close to the eyepiece center and then reinsert the illuminated eyepiece to complete polar alignment.  It seems to me that if the scope was already adjusted to polar alignment before the 90-degree turn, why would it be so far off?  Is there something askew with the wedge?

 

I do mostly astrophotography and do not know the night sky as well as others in my astronomy club.  I am the only one doing astrophotography in the small club using a wedge.  I have been using the scope and doing astrophotography since 2000.

 

My night sky software is Meade’s AutoStar Suite and I also have Stellarium.  I like the Meade’s better because I can usually call up pictures of the object I might want to photographic. 

I use PHD and have a ShortTube 80 guide scope with the StarShoot AutoGuider.  I have had this equipment for about two years now.

 

I believe I need to learn to do drift alignment, unless there is something wrong with the wedge, because I am getting too much error doing long exposures over 30-seconds.  If I am zoomed in using say, the Meade DSI, even 8-seconds has movement. 

 

 

As for scope’s balance, I use the Precision disc weight at the rear back of the scope and have a weight bar on the bottom to slide the barrel shaped weights on.  However, you only can get balance at a certain angle dependent on how you move the weights.  I do not move the weights afterwards.  I do the balance with what I am going to be using that night.  Not like a German equatorial mount where you can balance it for any angle.  Again you have to do the balance with what you are going to use that night on those also.  I am hoping that the gears are not the issue but PHD is showing too much movement/corrections.

 

The LX200GPS can train its gears but from what I read that only applies to the Alt-Az mounting position.  I have done that at times.  There is a PEC method in the manual but I do not understand it and probably would understand if there was a video out on it.

 

Sorry for the length of this post but I am at my wits end on trying to get better tracking.  Oh, I have used PHD’s guiding assistance and it has helped some at times but still getting movement.

 

Any help would be welcome.

 

Thank you,



#2 bamejer

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Posted 06 April 2017 - 06:59 AM

Use the azimuth and latitude controls on the X-Wedge to center Polaris in the field of view after the 90 degree turn.  This is what gives you polar alignment.


#3 Codeman

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Posted 12 April 2017 - 06:38 AM

I do that but PHD is still showing too much movement.  I guess I need to lean how to do the drift alignment method as well.  Do not understand it and there are not any good videos on doing a drift with a wedge.  Most are using the German equatorial mount.  Also, with trees and rooftops it is hard to get a star low near the horizon to do a drift.  Stuff I read recommends a star about 5-degrees above the horizon.  Sorry it took me so long to get to reading the response.  Thanks.



#4 Mark Sibole

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Posted 27 June 2017 - 04:11 PM

You have it all right but remember you have to train drives and when done do a pec train followed by at least 3 updates.I run the LX200 10 inch GPS and with multiple scopes piggybacked on top (not all at the same time) and with PHD guide,A good balance,a good pec and update and drives trained I can shoot 30 minute subs error free.

 

Regards

 

Mark


Mark Sibole
MTSO Observatory
Fife Lake, Mi.

http://astronomy.qteaser.com

#5 E Sully

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Posted 06 July 2017 - 03:50 PM

    I have an LX200 Classic so there are minor differences, but I have downloaded the GPS manual to see what Meade recommends. 

Have you done the initial set up recommended to get a good alignment?

    It is recommended to Calibrate sensors at least once to verify accuracy.  Make sure that your location is correct.  Also your timezone, GMT offset, and Daylight Savings Time options are correct.

    Training the motors in Alt-Az is a part of getting the scope ready for astrophotgraphy.  It corrects for backlash in the gears.  Anti-backlash setting can then be set so the motors change speed briefly to reduce delay from the backlash due to play in gear train.

Which option under GPS alignment have you used?  On, or At Start Up?  Maybe try switching between the two to see which works best.

In your initial Polar Alignment, after you have initialized the scope, set it to home position using the clutches.  Declination to 90 and RA to 00 hour.

After you hit enter and it rotates and asks you to center Polaris, you use the adjustments on the wedge to center Polaris.  Do not use the scopes clutches or paddle controls.

Learning how to drift align to refine your Polar Alignment is also needed.

PEC Training is different than Training the motors.  Visual observing does not need PEC training, but if you want to photograph, you will have to learn drift alignment and PEC training.

Make sure your power supply is good.  Also make sure if your scope is equipped with one, the button battery to retain memory is good.






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