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Equipment Discussions >> ATM, Optics and DIY Forum

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will1384
member


Reged: 02/22/13

How to center a Polar scope Reticle the easy way. new
      #5821175 - 04/25/13 01:15 AM

I have been having problems getting my Celestron VX mount aligned for astrophotography, and wanted to try a Polar scope, so I got one and tried aligning it during the day, but one of the tiny screws fell out and got lost, so I looked on the internet to find out what size they were, turns out they were metric M3 grub screws, and I don’t have them, but then I found a link: Permanent Polar scope Reticle Centring and he used rubber O-Ring to center the polar scope reticle, and I have few assortment boxes of rubber O-Rings, so I removed the two remaining reticle adjustment grub screws, and removed the reticle, its a small lens set inside a brass ring, the brass ring has a concave edge, that fits a O-Ring perfect.

I used two O-Rings:

AS568A-112 rubber o-ring on the reticle lens

AS568A-210 rubber o-ring as a spacer between the eyepice and the reticle lens

And now it looks to be perfectly center, one thing I will say is that you are likely to have to clean the reticle lens after you put the o-ring on because its a tight fit, and when pressing it on you will touch the lens.


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Pinbout
Postmaster
*****

Reged: 02/22/10

Loc: nj
Re: How to center a Polar scope Reticle the easy way. new [Re: will1384]
      #5821423 - 04/25/13 07:48 AM

any pics? sometimes I have a hard time understanding easy things...

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will1384
member


Reged: 02/22/13

Re: How to center a Polar scope Reticle the easy way. new [Re: Pinbout]
      #5823482 - 04/26/13 01:24 AM

OK, Here is a "little" how-to image.



and a link to a larger image because of the 800x800 size limit.

http://lh5.googleusercontent.com/-QAXknAP-5dI/UXoNSauhXZI/AAAAAAAACVI/Xr0RsnY...

Edited by will1384 (04/26/13 01:25 AM)


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John Carruthers
Skiprat
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Reged: 02/02/07

Loc: Kent, UK
Re: How to center a Polar scope Reticle the easy way. new [Re: will1384]
      #5823552 - 04/26/13 03:36 AM Attachment (12 downloads)

Fine for visual but how do you then adjust it for concentricity? or do you just rely on the housing/ring/reticle all being concentric? if that were the case they wouldn't need provision for adjustment in the first place?

I put a thin O ring behind the reticle (thanks Dion) to stop it falling out should the grub screws accidentally be loosened too much.
Replacing the grubs with thumb screws (another tip from Dion) is a great help, no more fiddling with little Allen keys in the dark.

adjusting polar scope;
http://www.awrtech.co.uk/oddtopic.htm#POLARSCOPE

adjusting and mods;
http://www.astronomyshed.co.uk/forum/viewtopic.php?f=19&t=4006


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will1384
member


Reged: 02/22/13

Re: How to center a Polar scope Reticle the easy way. new [Re: John Carruthers]
      #5824285 - 04/26/13 12:23 PM

When I rotate the RA axis from left to right the cross hairs stay centred, I could have done the same with the grub screws but this was a lot easier.

Quote:

do you just rely on the housing/ring/reticle all being concentric?




Yep.

Quote:

if that were the case they wouldn't need provision for adjustment in the first place?




I am not sure, maybe the aliment is slightly off using this method, even if it looks good, but its no better than I would have done using the grub screws.


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donnie3
Carpal Tunnel


Reged: 12/15/04

Loc: bartlesville oklahoma
Re: How to center a Polar scope Reticle the easy way. new [Re: will1384]
      #5838911 - 05/03/13 07:01 PM

will1384, where did you get your o rings. I tried to find them at atwoods and lowes and all they had was plumbing o rings. im going to try true value tomorrow. thanks, donnie

Edited by donnie3 (05/03/13 07:03 PM)


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MartinTreadgold
super member


Reged: 04/17/13

Loc: Netherlands
Re: How to center a Polar scope Reticle the easy way. [Re: donnie3]
      #5842063 - 05/05/13 05:19 PM

i like the thumb screws... great tip.. thanks

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will1384
member


Reged: 02/22/13

Re: How to center a Polar scope Reticle the easy way. new [Re: donnie3]
      #5860408 - 05/14/13 05:01 PM

Quote:

will1384, where did you get your o rings. I tried to find them at atwoods and lowes and all they had was plumbing o rings. im going to try true value tomorrow. thanks, donnie




I had got some cheap O-Ring assortments at Harbor Freight Tools, they were under $10 for almost 400 O-rings, I had also ordered some from Amazon in the past for around the same.

I got playing with my polar scope today, and decided to get it exactly centered, not just very close, and tried using some metric screws I saved from an old laptop I disassembled, took very little time to get it centered, less than 10 minutes, I also rotated the polar scope reticle to better line up with what the night sky looks like now, I left the O-Rings installed.

Edited by will1384 (05/15/13 08:08 PM)


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