Polar Alignment of LX200R and Ultra Wedge

For The Southern Hemisphere by Chris James


Shortcut - Process



Return To How To Menu

When and Why To Use This Process

This shortcut process described here, assumes that the reader is familiar with the full process described in the polar alignment document located on this web site @ http://www.cwjames.info/astro/howto/polaralignment.htm


In order to make more efficient use of the time taken to setup prior to an imaging session I have separated the Drift Alignment process and Autostars Synch to the night sky for the goto functionality.


This allows you make the best use of the time before the sun sets by allowing you to fit all the required accessories for the evenings imaging session during daylight whilst waiting for the stars to come out to begin the drift alignment. Accessories such as and guide scopes, cameras, dew shields and cameras etc can now be fitted and you will not be required to move the scope to the Polar Home Position to complete Auto Stars alignment. By separating Auto Stars synch process you can then Synch Autostar to the night sky without having to move your fully equipped scope around the SCP as would normally be the case.


Now when the stars begin to show, you can now do your drift alignment with the scope fully equipped with the required accessories and once the drift alignment has been completed a new process is used to synch Auto Star for the goto function to operate correctly.


Overview Of The Steps Required

1.    Mount The Scope On Wedge. (as per the original polar alignment document)

2.    Attach All The Required Accessories To Scope.

3.    Setup Autostar to begin tracking.

4.    Do The Drift Alignment. (as per the original polar alignment document)

5.    Align Autostar To the Night Sky.



1 - Mount Scope On Wedge

To mount the scope, follow all the steps as detailed in the full polar alignment document on this web site.


Stop following the instructions from the full documentation when you get to the heading, Set Polar Home Position


Dont take any short cuts to this point.


Note, if the basic wedge alignment is NOT true at this stage, you will not be able to achieve a good Drift Alignment or be able to Synch Autostar to the night sky so you can use the GOTO will any degree of accuracy. So double check with your compass (factoring in your local magnetic deviation) that the wedge is pointing is the right direction. Use your spirit level to confirm that the base of the Wedge is level in all directions and the Tilt Plate has been set to the complementary angle for your latitude as described in the full document using your protractor.


2 - Attach All The Required Accessories To Scope

Continue attaching all the required accessories to the scope for the evenings session, for example, Guide scope, dew shield and heaters, wiring looms for camera and other electronics as required. Align the guide scope, finder device to the main scopes axis and complete any balancing of the final setup as required.


Once everything is attached and ready ensure the RA clutch is locked in the middle of the RA travel as described in the full document.


3 - Setup Autostar To Begin Tracking

Now turn the power on to Auto Star and wait for Smart drive init to complete. I will assume you have setup the scope and placed Autostar in the Polar mode for use with the wedge at this stage. If not go back and ensure its in Polar mode before proceeding.


Basically we need to tell Autostar NOT to do the alignment routine by pressing the Mode key when prompted to Align or go to the Menu, we will press mode to go to the menu. Auto star will then take a GPS fix to get your location and the time and date so it can workout the Local Sidereal Time. It is recommended that you set GPS Alignment to AT START as this will help avoid one of the firmware bugs in Autostar. Once the GPS alignment has completed, continue to press the mode key to escape the Alignment menus until you are at the top level menu.


Autostar has now done a GPS fix so it knows your location and the Local Sidereal Time and it is now tracking the sky with the RA motor only running. We have NOT synch it to the sky, so any GOTO commands will not work at this stage, however we will come back later to fix this problem.


A summary of Auto Stars Responses and your input is as below.


Autostar Responses

Your Input

Press 0 To Align or Mode for Menu

Press Mode (To go to the Menu)

Taking a GPS Fix


Align: Easy

Press Mode (To escape this level of Menu)

Setup: Align

Press Mode (To escape this level of Menu)

Select Item

Do nothing - Auto Star will now be tracking





4 - Do The Drift Alignment

If the sky is dark enough to see stars you can now begin to do your drift alignment. I will not explain this procedure in detail here as it is explained in full in the full Polar Alignment document on this web site.


Full Polar Alignment document can be found at http://www.cwjames.info/astro/howto/polaralignment.htm



Description: Description: DriftAlignmentAzimuthSmall

Azimuth Adjustment


Show Animated GIF




Description: Description: DriftAlignment-AlitudeAdjus

Latitude Adjustment


Show Animated GIF


Polar Alignment document using your imaging camera can be found at http://www.cwjames.info/astro/howto/polar_alignment_ccd.htm



5 - Align Autostar To The Night Sky

Now that the drift alignment has been completed all that remains is to synch Autostar to the night sky. If you remember we bypassed this section before so currently our GOTO commands will not work. We need to slightly modify the standard polar alignment process in order to keep the imaging train clear of anything now that we have the all the required accessories attached to the scope. We will align Autostar to the night sky without risking the imaging train but at the same time let Autostar know where the hard RA stops are.


We are now going to do a modified Polar One Star alignment.


From Autostars top level menu select ALIGN and then select ONE STAR. Autostar will now prompt you to put the scope in the Polar Home position. When setting the scope to the Polar Home position ONLY do the HA location for polar home and leave the OTA in a safe position so your imaging train clears the base. Setting the DEC to somewhere close to 0 for example should keep the imaging train clear of the base. The full instructions for setting HA location for the Polar Home position are in the full polar documentation under the heading ADJUSTING THE RA ZERO POSITION.


Once you have the HA location set correctly, press ENTER and Autostar will now slew to Sigma Octanis. When the slew is complete simply press the ENTER key without checking the star in the eyepiece/CCD as we have already done a drift alignment. Autostar will now select an alignment star and slew to it. When the slew is complete, release the Dec clutch and move the OTA to centre the selected star. One you have got the star approximately centered as best as possible in the eyepiece/CCD then you can lock the Dec clutch and complete the centering with Autostars arrow keys and then press ENTER to complete the Polar One Star Alignment.


Autostar should now be able to use its GOTO function to other objects in its data base.


What I strongly recommend doing now before going to your first dim deep sky object is to select a bright object close to your dim target. Now do a goto to the bright object and when the slew has completed, use auto arrows keys if required to centre the bright object on your CCD. Dont unlock the clutches this time, just use auto stars arrow keys to centre the bright target. Now hold the ENTER key down for 3 seconds plus and release it. Autostar will be once again prompting you to press ENTER to synch the target. Press the ENTER key when you have the target centered on the CCD.


Now do a GOTO to your dim target and the chances are it will be on your CCD after doing an appropriate exposure for your dim object. Once you have the dim object centered on your CCD, do another synch on it as just described above.


I strongly recommend you repeat this process for every new dim target you select, especially if its in a area of the sky some distance from your last synch target. In other words, for every new dim target, select a bright target close by and synch on it first using your CCD, then use the goto to go to the dim target. Once the dim target is centered on the CCD then also synch on it. The accuracy of your goto will get better and better as you select more targets during the course of the evening with your targets appearing on the CCD after the slew to it has completed on the first go. Alternatively you could turn on Autostar built-in High Precision Mode which effectively does this for you. I like to choose when and what bright object to use to synch on and as a result I leave this mode turned off, you however may choose to turn it on.


Important - If you find that the goto accuracy is only good for objects close to where you have done your last synch, then I strongly suggest you re check the wedges basic alignment with your compass, spirit level and protractor as described in the full Polar Alignment document and confirm the Drift Alignment is ok. Either one of these alignments being incorrect will directly impact on Autostars ability to do accurate goto commands for all objects across the night sky. NO amount of target synching can make the goto work for all objects under these conditions.




Written by:

Chris James

55 Blackthorn Road

Greenwood WA 6024


















Return To How To Menu