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AVX Alignment During the Day

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#1 StrangeDejavu

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Posted 01 February 2014 - 03:44 PM

What would be the best way to get good alignment before the sun sets? Mercury will be directly beneath the Moon tonight in the West, and I want to be ready to go as soon as the Sun is at a safe distance near the horizon.

#2 end

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Posted 01 February 2014 - 03:55 PM

I use the following routine which I learned from one of the other posters on this board. I subsequently slightly modified the protocol, but this works quite well.

1. Power on the mount as normal: either align the index marks (CGEM or CG-5), or let the homing switches do their thing (CGE-PRO). Enter time and site information as required.

2. Select “Quick Alignment”.

3. Turn off tracking.

4. Register the OTA’s RA to the Mount’s RA: In the Utilities menu, find “Goto Axis Position”. Enter azimuth 180° 00’ 00”, altitude 90° + local latitude to put the mount with the scope on the west side with the OTA pointed north. Release the RA clutch and use a bubble level to make the counterweight shaft perfectly horizontal. Re-tighten the RA clutch.

5. Register the OTA’s declination to the Mount’s declination: Again, find “Goto Axis Position”. Enter 90° 00’ 00” for azimuth and 180° 00’ 00” for altitude and press enter. The mount should slew such that the OTA is pointing to the western horizon and is level. While in this position, loosen the declination clutch and use a bubble level to make the OTA perfectly horizontal. Re-tighten the declination clutch.

Steps 4 & 5 are basically accounting for the fact that your tripod or pier is probably not perfectly level.

6. Correct Mount & OTA’s polar alignment in Altitude: Go back to “Goto Axis Position” again. This time, go to 180° 00’ 00” for the azimuth and enter 90° + local latitude for latitude. Hit enter. This time, the mount will slew so that the OTA is on the west side of the mount and level pointed north. Use a bubble level again to ensure that the OTA is perfectly horizontal. This time, though, do not release any clutches and do not hit any buttons. Use the mount's altitude adjustment to level the OTA. Do not release any clutches and do not hit any buttons on the hand controller.

7. Turn on tracking.

8. Correct Mount & OTA’s polar alignment in Azimuth: Use goto to pick any object that you can see during the day, like the Moon or the Sun or Venus. When the mount is done slewing, use the mount's azimuth adjustment to center the object. Do not release any clutches and do not hit any buttons on the hand controller.

The mount is now polar aligned in both altitude and azimuth. In my experience this process will result in a polar alignment error of less than 1 degree in both axes. When it gets dark enough, you can now power cycle the mount, do your normal 2+4 alignment routine and start using the mount. If necessary / desired a subsequent ASPA (Celestron’s All Star Polar Alignment) should improve your polar error to less than 10 arc minute in both axes.

#3 StrangeDejavu

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Posted 02 February 2014 - 01:17 AM

Great advice end, thanks for your help. Seems a little time consuming, but sounds much more accurate than aligning on the Sun.






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