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Installing a polar scope

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#1 ColdNights

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Posted 08 May 2021 - 09:40 PM

Some assistance please.  My friend wanted to put a polar scope into his old Celestron Advanced GT GoTo mount.  He purchased what Celestron told him would fit the old mount.  The photos show before work, during work and after work.  I am confused as to why the existing parts had to be removed.  However, the new polar scope would not fit any other way.  I am not sure as to why the old items had to be removed.  The instructions were very vague.  I could not find any YouTube videos on this.  Only videos I found were how to do polar alignment and adjust the polar scope.  On my SkyWatcher EQ6-R Pro, I just use my polar scope to polar align and never use the dials.  I use the Polar Scope Align Pro phone app to see where Polaris is to be on the illuminated clock and match it. 

 

Can someone elaborate for me if I installed this item correctly?  Also, what I need to do with the dial setting related to the rings that get the grub screws?

Photos with text are in ColdNights Album that I set up tonight.

Thank you.



#2 robbieg147

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Posted 09 May 2021 - 05:33 AM

I assume you mean the AVX mount? this does not come with a polar scope and needs to be purchased separately.

 

You need to unscrew and remove the plastic cover at the back of the RA axis and just screw in the polar scope, then turn the Dec axis 90 degrees so you can see through the scope to align.

 

Don't worry about dials etc. just use a app on your phone to give you the relative position of Polaris.

 

If you have not Polar aligned before accurately level the top of the tripod and aim the pin North with a compass if you have one, and wait for Polaris to appear, the first star you see will be Polaris in this area of the sky.

 

Don't worry about calibrating the Polar scope for now anyway.

 

Good luck.



#3 RTLR 12

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Posted 09 May 2021 - 08:31 AM

You have the scope installed correctly. The parts that you removed aren't required for the scope that you have. Here’s some instructions for the use of the scope.

Stan

https://s3.amazonaws...raxixfinder.pdf

https://youtu.be/wh5kipL1mPA

Edited by RTLR 12, 09 May 2021 - 08:33 AM.


#4 ColdNights

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Posted 09 May 2021 - 11:01 AM

Thank you both for your replies. 
The scope is not an AVX.  AVX came out a few years later as I understand.  The mount is an Advanced Series GT (CG-5 Equatorial) per the manual.  The Astronomy Club I belong to also has this mount and it too does not have a polar scope.  However, the Club’s mount is in a dome and on a pier.  It is aligned using plate solving so no need for the polar scope.  My friend’s same mount is mobile with a tripod.  Although one can just point it north and do the star alignment and calibration star alignment, it seems that a polar alignment via a polar scope has it slewing on the target during alignments better than just pointing the mount north.  I have been working on his mount and found that viewing through the polar scope hole and getting Polaris in the near center of the hole has the star alignment closer than just pointing the mount north.  Thus, the reason for getting a polar scope.
I have seen that YouTube video before.  The Polar scope’s markings inside are identical but the outside dial features are a little different.  The mount, I am working on, time circle (right accession dial) has a smaller indicator “RA” item on it next to the thumbscrew.  The video looks to have just a line for the item I am talking about.  If I tighten down the thumbscrew for the time circle, I can tell you that the scope seems to be unable to rotate as well as moves the dial.  The same happens on the Clubs’ mount also.  The instruction you linked came with the polar scope, so I have that also.  I am thinking that the dials are going to be a bit useless.  The video seems to show everything rotated well, without binding, but that does not happen on this mount.  Any ideas on this issue?  See Picture-06 “ColdNights Album” for the thumbscrew and “RA” item next to it.

Thank you.



#5 robbieg147

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Posted 09 May 2021 - 12:48 PM

What I do is to use a app on my phone (I use PolarisView) to give me the relative position of Polaris, then just forget about lines and setting circles and dials and position Polaris in the Polarscope so it's in the same relative position as you look through the polarscope.

 

So if the app on your phone is showing Polaris at 5 o clock then looking through the polarscope use the mount bolts to position Polaris on the circle at 5 o clock.

 

This will get you reasonably close, I then switch to the Polemaster for my final accurate align (or could use something like Sharpcap).

 

For imaging the polarscope is not accurate enough, though occasionally it's almost spot on when checking with the Polemaster.



#6 RTLR 12

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Posted 09 May 2021 - 01:18 PM

It depends on the version of the firmware on the hand controller, but I use All Star polar alignment. I do it after the 2 star alignment procedure and I use the last calibration star as my polar alignment star. It only takes less than a minute to polar align the mount this way.

Just for FYI polar alignment has very little to do with the accuracy of go-to’s.

Stan

Edited by RTLR 12, 09 May 2021 - 01:21 PM.


#7 ecuador

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Posted 13 May 2021 - 01:16 PM

You already have Polar Scope Align, which supports this reticle and provides instructions on how to use it - the RA graded setting circles can be used to get quite a precise alignment following those instructions, or from the sound if it you are probably going to be fine just loosely matching the rotation of the reticle on the app.

Of course the polar scope has to be aligned with the RA axis too.


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