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Atlas EQ-G and new Synscan polar re-align

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#1 tonyb

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Posted 09 September 2013 - 04:57 PM

I followed the Atlas EQ-G and SynScan Polar re-align routine last night, but after step 7 below, the mount slewed to a star no where near the reference star - more than 10-20 degrees away. For example, my reference star was Vega - almost overhead. In step 7 the mount slewed to the north-east only a few degrees about the horizon and my house was in the way.

INSTRUCTIONS:
1. Level the tripod of the EQ GOTO mount and point to the north.
2. Rough align the RA axis of the mount to the celestial polar axis by pointing to the north and setting the latitude on the EQ mount.
3. Do a 2-Star alignment or 3-Star alignment with the SynScan hand control. 3-Star alignment is recommended for better accuracy and error compensation. If use 2-Star alignment to align the GOTO mount, please make sure that the “cone error” is eliminated.
4. After completing the Star alignment, browse to “Polar Re-align.>” submenu under Setup\Alignment menu of the hand control and then press ENTER.
5. The hand control will prompt, “Select any star:” and provide a list of stars, which can be used as the reference star for the Polar Re-alignment. Select a star from the list and press ENTER. The EQ Telescope GOTO mount will slew and point to the selected object.
6. When the hand control prompt, “ALIGN OBJECT ”, use the directional keys to center the selected reference star to the center of the finder scope and then to the center of the eyepiece. When done, press ENTER to confirm. The hand control will prompt the displacements of polar misalignment of the EQ mount, Mel and Maz, in both elevation and azimuth directions respectively.
7. Press ENTER and then the mount will slew to the same reference star again, but the reference star will not locate at the center of the eyepiece at this moment. Try to use the Altitude Adjustment T-bolts and the Azimuth Adjustment Knobs to adjust the mount as doing the adjustment for polar alignment, but just draw back and center the reference star to the center of the eyepiece. In this procedure, you cannot use the directional keys to center the object and the directional keys are disabled to driving the motors.
8. When finish the adjustment of the mount for the Polar Re-alignment. Press ENTER to confirm and check the new calculated polar misalignment, Mel and Maz. Press ENTER to exit Polar Re-alignment function. During these Polar Re-alignment procedures, you may press ESC to go back to previous step, if necessary.
9. Check the polar re-alignment result. You may repeat the Polar Re-alignment procedures from step 3 to step 8 to get better polar alignment, if it is necessary.

#2 NigelM

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Posted 10 September 2013 - 06:54 AM

Update to firmware 3.35 - this has changed the procedure so that you adjust azimuth and altitude separately. Seems to work much better.

NigelM

#3 WillCarney

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Posted 10 September 2013 - 10:28 AM

I tried the new 3.35 and did the azimuth-altitude separately as mentioned. It was still half the sky off like his. I don't use it at all know. I usually get less than 1/2 degree in either axis using just the scope. William

#4 John Carruthers

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Posted 11 September 2013 - 03:01 AM

Will, do you have any cone error in your setup? do you use a crosshair EP when aligning? I find a 3 star align> polar align> 3 star align gets it within a few arc minutes. Further iterations get it closer still.

#5 tonyb

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Posted 11 September 2013 - 12:25 PM

Thanks. I updated to the 3.35 and it worked well for me.

#6 WillCarney

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Posted 11 September 2013 - 01:48 PM

I have not done a cone error but do use a cross hair. I gave up on polar align by hand controller. I usually get with in 1/2 degree by eyesight. Good enough for most observing. I'll drift align if I need better alignment.

By the way. I've tried the 3-star, polar, 3-star. Tried just about everything. Always by the second to third polar align star it's so far off as not in the field of view of a 6x30 finder. The last time was 30 and 40 degrees for both axis. I won't try again.
William

#7 neptun2

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Posted 14 September 2013 - 03:19 AM

That is very strange. for me it works very well with 3.35. When doing the initial 3-star align how far off is your first alignment star?






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