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The Jackal

Celestron Advanced VX Precision Alignment.

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So I wanted to list my Alignment procedure as I am looking for advice to get more accurate alignment. Please would someone be so kind to explain to me where I am going wrong or where can I improve.

First of all I live in the Southern Hemisphere so I don't have Polaris to point at. My mount also points South when setting up instead of North.

I am constantly getting trails on my starts and cant find any proper setup instructions for the Advanced VX as the manuals setup guide is to basic and more for planetary use.

Setup is as follow.

1. Level tripod and make sure peg on top points South'ish.

2. True South is -18deg for me so I make sure I accommodate for that and setup the peg pointing True South instead of Magnetic South.

3. After mounting everything that is needed like the Scope, weights and guiding camera I proceed to center everything in the home position.

4. Next I make sure my latitude is set on 27deg for my location then I switch the mount on.

5. Now I start a two star alignment and add around 3 calibration starts.

6. Next up I go to Peacock and start the Polar Alignment procedure. I polar align and adjust the scope with the hand controller as it is always out after two star alignment (including 3 calibration stars). I then proceed to adjust the latitude and altitude on the nobs in order to center the star in the scope.

7. After all this is done I go to the home position and re do everything again from step 5. I proceed to do this 3 times.

I dont know if I am not picking calibrations stars or where I go wrong but my scope is never perfectly alligned and my stars trail after 1min exposure. I have tried Polar aligning the scope about 3 or 4 times in a row instead of parking it and starting everything over and this sometimes gives better results. As soon as the remote tells me "Polar Align is complete" I do it 3/4 times more.

I have also tried Alignmaster and find it rather useless.

Assistance would be highly appreciated.

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I'm in the Northern Hemisphere so I cannot comment about pointing South. I basically do the same as you BUT I don't do your 7. Once I have done the first Polar Align I then unsync and recallibrate using the original alignment stars as described in the manual. I then slew to a star on the opposite side of the Meridian and add this as a calib star as described in the manual. I generally get an error of well under 5' on the first ASPA (usually about 1'). Also I strongy recommend using an illuminated reticule eyepiece or camera with cross hairs (like Als Reticule) as you cannot locate stars centrally in an ordinary EP with enough accuracy.

If you turn it off and go back to the home position you are introducing an error because you cannot hope to get it set to exactly the home position you used the first time as the marks are not precise enough. I would try it by using the unsync method and see how that goes. Also I strongly advise making sure that you have the latest firmware installed which you can get from the Celestron website.

Peter

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Hi Peter. Thank you for the reply and advise. 

Which manual talks about the unsync and re-calibrate as mine didn't show that? Can you also please explain how to un-sync the scope and should this be done on the star that was just polar aligned? 

Also are you saying that Peacock is not a good star to work with as it is not on the Maridian ( its close'ish) ? The other thing is what do I do If I cant slew to the opposite side of the Meridian as I have building that block that side.

I use Backyard EOS with my Canon Camera as a lens. Surely that should give me close enough to center?

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On page 29 of the manual onwards there are instructions to carry out the ASPA and the unsync is on page 30. It says:

Updating your Star Alignment
After polar alignment, it is a good idea to check the pointing accuracy of the telescope to see how much it may have been affected by moving the mount. Since the polar alignment process requires you to “sync” the telescope on a bright star before you begin, it will be necessary to undo the sync before re-aligning. To undo the sync:
• Press the Align button and use the Up/Down buttons on the hand controller to select Undo Sync from the list, and press Enter. The message Complete will display on the
LCD.

You can download the manual here http://www.celestron.com/support/manuals-software

I am not saying anything about Peacock because I am not aware of it. You should slew to the other side of the Meridian for a calib star - you should be able to see a high one surely even with the building. Using BYE should be fine - I always carry out the PA using an eyepiece before adding the camera.

I urge you to read the manual and follow the instructions for ASPA as stated.

Peter

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So after my polar alignment is complete, I can stay on the star unsync and do the hole process again?

The manuals talks about "For additional all-sky pointing accuracy, it is a good idea to align on at least one additional calibration star located on the opposite side of the Meridian." Do they mean I have to unsync again and polar align on a star on the opposite side of the Meridian or is this just to add another calibration star?

Thank you for the manual link. I must have skipped this complete. So glad you pointed this out as I hated the alignment process as it took me more than 1:30min to complete.

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Once you complete your first PA you unsync and then check the alignment using the original alignment stars then you slew to a star on the opposite side of the Meridian and without first centering it you go align, calib star and then centre it and it will be added as an unassigned star. Only do another ASPA if you are not happy with the PA error which you can check AFTER you do the above steps.

Peter

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I did a little check list for myself which you might find useful

Polar Alignment

  1. Slew to bright star high and near meridian.(not overhead)
  2. Press Align – Polar Align – Align Mount.
  3. Scope will slew away and back.
  4. Centre star in finder – Enter – centre star in EP. Scope will sync.
  5. Enter – Use Lat and AZ bolts to centre star – Enter

Updating Star Alignment

  1. Press Align – Undo sync – Enter
  2. Slew to one of the original alignment stars.
  3. Press Align – alignment stars – select star.
  4. Centre star – Enter- Align.
  5. Repeat for other Alignment star.
  6. Slew to bright star on opposite side of Meridian.
  7. Press Align – Calib stars – Enter.
  8. Centre star – Enter – Align.
  9. Press Back – Align – Polar Align – Display Align.

Good luck

Peter

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Okay so that explains allot. I just have a couple of questions. Sorry if they sound dumb, I just want to make sure I am doing it right.

Updating Star Alignment

  1. Press Align – Undo sync – Enter (is this done on the same star I did the initial polar alignment on or another star?)
  2. Slew to one of the original alignment stars. (this is one of the 2 star alignment stars or calibration stars that I added?)
  3. Press Align – alignment stars – select star. (Lets say I used Canopus as one of my alignment stars. Do I go back to it?)
  4. Centre star – Enter- Align.
  5. Repeat for other Alignment star. (When you say for other Alignment stars, do I do it on all of them or just one or two?)
  6. Slew to bright star on opposite side of Meridian. (This is a new star that I didn't use for the alignment process or can I use one the I used when aligning?)
  7. Press Align – Calib stars – Enter.
  8. Centre star – Enter – Align.
  9. Press Back – Align – Polar Align – Display Align. (this is just to get a reading to see how for I am out?) Havnt used this function before.
Edited by The Jackal

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Okay so that explains allot. I just have a couple of questions. Sorry if they sound dumb, I just want to make sure I am doing it right.

Updating Star Alignment

  1. Press Align – Undo sync – Enter (is this done on the same star I did the initial polar alignment on or another star?)
  2. Slew to one of the original alignment stars. (this is one of the 2 star alignment stars or calibration stars that I added?)
  3. Press Align – alignment stars – select star. (Lets say I used Canopus as one of my alignment stars. Do I go back to it?)
  4. Centre star – Enter- Align.
  5. Repeat for other Alignment star. (When you say for other Alignment stars, do I do it on all of them or just one or two?)
  6. Slew to bright star on opposite side of Meridian. (This is a new star that I didn't use for the alignment process or can I use one the I used when aligning?)
  7. Press Align – Calib stars – Enter.
  8. Centre star – Enter – Align.
  9. Press Back – Align – Polar Align – Display Align. (this is just to get a reading to see how for I am out?) Havnt used this function before.

1. The star you used for PA.

2. The original alignment stars.

3. Slew to it then press alignment stars etc

5. The others star(s) you used on the original alignment.

6. Just one from the other side of the Meridian.

9. Correct - this will show your PA error.

Peter

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No problem, glad to help. Good luck.

Peter

So this is just an update with a question.

I did an alignment last night and when I went to the opposite side of the meridian it somehow lost my calibration starts. Anyway, I think the alignment was good. Peter please let me know if this PHD graph is satisfactory. Can you also let me know if they say the opposite side of the meridian do they mean if I am on a star on the south close to the meridian, do I have to go to a star in the north close to the meridian or one just on the other side of the southern one but on the opposite side of the meridian?

post-39914-0-35010200-1448434436_thumb.j

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A star on the opposite side of the Meridian is just that - if you do your initial alignment in the West then you slew to one in the East.

"I did an alignment last night and when I went to the opposite side of the meridian it somehow lost my calibration starts" - sorry but I don't understand this.

What PA error was shown when you did Polar Align - Display Align? This is the crucial thing.

As I have said, as long as you stick to the method shown in the manual it should all work out ok.

As for your PHD - your Hys looks very low. The answer really is that if it provides good round stars then it's ok. If not then it isn't.

Peter

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