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Right angle polar scope?

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#1 James Cunningham

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Posted 22 December 2018 - 03:58 AM

Is there something that can be done to make a polar scope right angle so that you can stand to get the alignment?  Thanks

Jim



#2 Astrojensen

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Posted 22 December 2018 - 04:12 AM

Yes.

 

https://www.teleskop...her-D-26mm.html

 

https://www.teleskop...lar-finder.html

 

 

Alternatively, you can use the main scope as a polar scope, too, which can be super accurate and is very easy to do. 

 

 

Clear skies!
Thomas, Denmark


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#3 James Cunningham

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Posted 22 December 2018 - 04:17 AM

$125.00 U?S? Is mighty expensive.
Jim

#4 Astrojensen

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Posted 22 December 2018 - 04:26 AM

You think so? 

 

I can recommend the main scope method. Doesn't cost anything extra and is very convenient and precise. You only need a crosshair eyepiece, preferably of fairly long focal length, a 25mm is fine, and a map of the polar region. It is FAR more convenient than using the diminutive polar borescopes. 

 

 

Clear skies!
Thomas, Denmark


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#5 agmoonsolns

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Posted 22 December 2018 - 04:28 AM

During the 1980s, Celestron sold (made by Vixen in Japan) a super nice 8x50mm right-angle finderscope with an illuminated reticle set up for doing polar alignment. It could be used as both a polar alignment telescope and as a standard finder. Wonderful item, extremely well made with a volcano-top eyepiece and a nice mirror diagonal. It's only fault was you needed to use a non-standard battery for the illuminator (batteries can be found on Amazon).


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#6 James Cunningham

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Posted 22 December 2018 - 04:29 AM

How do you use the main scope to do a polar alignment?
Thanks

#7 Shorty Barlow

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Posted 22 December 2018 - 05:08 AM

I'm pretty sure 365Astronomy had a right angled Sky-Watcher polar finder that was cheaper than the TS one (which I bought).

 

https://www.365astronomy.com/home.php

 

I can't find it on their site now though. It might be worth enquiring. I only saw it after I'd bought the TS one.



#8 Astrojensen

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Posted 22 December 2018 - 05:11 AM

How do you use the main scope to do a polar alignment?
Thanks

There are three methods. All three require a crosshair eyepiece: 

 

1: Use the setting circles on the mount to aim at the position of Polaris (or any other star!!) and center it in the crosshair eyepiece. This method requires you to first align the setting circles. 

 

2: Use the setting circles to aim the scope at exactly 90° DEC (RA doesn't matter) and then aim directly at the celestial pole among the stars. An accurate map of the region is needed. If you use a diagonal on the scope, you need a mirror-reversed map that matches the view in the diagonal. 

 

3: This method can be used on any mount, also those without setting circles. First aim the scope at roughly 90° DEC and with the scope "on top" of the mount (counterweight shaft vertical), first align the horizontal crosshair with the pole; then turn the mount 90° in RA, so that the scope sits to one side of the mount and align the vertical crosshair with the pole. Repeat the process if necessary. By turning the mount 180°, you can check for parallax errors in the mount. 

 

 

It was CN member Daquad that made me aware of method #2 and #3. I'm using #2 myself and it really is crazy accurate, considering how simple it is. You can very easily get polar aligned to an accuracy of a couple of arc minutes in just a few minutes, once you get familiar with the process. All this at the convenience of the big, bright and comfortable view in your main scope. The scope shouldn't be too big, though, lest the field of view becomes too narrow. 

 

 

Clear skies!
Thomas, Denmark


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#9 Ed D

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Posted 22 December 2018 - 07:57 AM

In addition to the suggestions already made, you can use a crosshair eyepiece to do drift alignment.  Do a Google search on POLAR DRIFT ALIGNMENT.  One of the hits is a good article by Sky&Telescope.  YouTube has a lot of videos on the subject, too.

 

In your sig you list a couple of imaging cams.  I have successfully used the Polar Alignment feature in SharpCap using my AT72ED.  You may want to give it a try with your smallest, fastest refractor.  Once polar aligned you can switch the scope if you want.  There are a lot of YouTube videos on this.

 

I am able to do 1 minute exposures with tight round stars using the SharpCap polar alignment.  It's that good.  The only problem is light pollution is severe here and sometimes it doesn't want to work.  The full moon also makes it almost impossible.  That's when I use drift alignment.

 

Ed D


Edited by Ed D, 22 December 2018 - 07:59 AM.


#10 spaceoddity

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Posted 22 December 2018 - 08:31 AM

During the 1980s, Celestron sold (made by Vixen in Japan) a super nice 8x50mm right-angle finderscope with an illuminated reticle set up for doing polar alignment. It could be used as both a polar alignment telescope and as a standard finder. Wonderful item, extremely well made with a volcano-top eyepiece and a nice mirror diagonal. It's only fault was you needed to use a non-standard battery for the illuminator (batteries can be found on Amazon).

https://agenaastro.c...s_power_reviews



#11 James Cunningham

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Posted 22 December 2018 - 08:41 AM

That is too expensive plus, it's out of stock.  Thanks anyway.

Jim



#12 James Cunningham

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Posted 22 December 2018 - 09:13 AM

I have read that you can use a camera right angle viewer on the Polar scope.

Jim



#13 Astrojensen

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Posted 22 December 2018 - 09:28 AM

I have read that you can use a camera right angle viewer on the Polar scope.

Jim

That is exactly what the two I linked to, are. They just come with the adapter you need already made.

 

 

Clear skies!
Thomas, Denmark



#14 sg6

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Posted 22 December 2018 - 09:31 AM

People have used a camera right angle attachment that fits the viewfinder of a camera. Not sure how it can be attached, also unsure of the optics - I assume that it either does nothing as in "Collimated light in, collimated light out and no magnification" but unsure of the operation overall.

 

If inexpensive may be worth a go.

Maybe ask on the DIY section if anone has done it and how - and pictures.

 

I would find out soon as it seems people do not use the viewfinder much these days. So they may disappear.


Edited by sg6, 22 December 2018 - 09:32 AM.


#15 25585

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Posted 22 December 2018 - 09:32 AM

There are three methods. All three require a crosshair eyepiece: 

 

1: Use the setting circles on the mount to aim at the position of Polaris (or any other star!!) and center it in the crosshair eyepiece. This method requires you to first align the setting circles. 

 

2: Use the setting circles to aim the scope at exactly 90° DEC (RA doesn't matter) and then aim directly at the celestial pole among the stars. An accurate map of the region is needed. If you use a diagonal on the scope, you need a mirror-reversed map that matches the view in the diagonal. 

 

3: This method can be used on any mount, also those without setting circles. First aim the scope at roughly 90° DEC and with the scope "on top" of the mount (counterweight shaft vertical), first align the horizontal crosshair with the pole; then turn the mount 90° in RA, so that the scope sits to one side of the mount and align the vertical crosshair with the pole. Repeat the process if necessary. By turning the mount 180°, you can check for parallax errors in the mount. 

 

 

It was CN member Daquad that made me aware of method #2 and #3. I'm using #2 myself and it really is crazy accurate, considering how simple it is. You can very easily get polar aligned to an accuracy of a couple of arc minutes in just a few minutes, once you get familiar with the process. All this at the convenience of the big, bright and comfortable view in your main scope. The scope shouldn't be too big, though, lest the field of view becomes too narrow. 

 

 

Clear skies!
Thomas, Denmark

Once Polaris is bullseyed, you can rotate setting circles to its RA and Dec co-ordinates, which then can ve used to find other things. 



#16 Astrojensen

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Posted 22 December 2018 - 10:13 AM

Once Polaris is bullseyed, you can rotate setting circles to its RA and Dec co-ordinates, which then can ve used to find other things. 

I must stress that you DO NOT aim at Polaris with method #2 and #3, but at the true celestial pole, and that in order to use method #1, your setting circles must already be aligned. You do not need a star to align the setting circles, only an accurate spirit level. 

 

 

Clear skies!
Thomas, Denmark



#17 PatNois

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Posted 02 January 2019 - 07:06 PM

This is a photo of a right angle Nikon camera finder that I attached to my Losmandy polar scope. A piece of pvc pipe which I drilled and tapped for these plastic screws. Works beautifully.

Attached Thumbnails

  • 0A588E41-145B-4FC5-9D55-5B9E770332DE.jpeg

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#18 lazypineapple

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Posted 02 January 2019 - 07:36 PM

I made my holder from a Pill Bottle top.
The right angle viewer is for a Canon 
Cheap 15.00
IMG 2985
IMG 2982
IMG 2987
IMG 3013

 

 


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#19 Rock22

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Posted 02 January 2019 - 08:31 PM

 

I made my holder from a Pill Bottle top.
The right angle viewer is for a Canon 
Cheap 15.00
 
 
 
 

 

 

Hmmm.... I am very tempted to try this.  There are many of these camera right angle finders on e-bay, new and used.  Does alignment of the right angle finder with the polar scope need to be precise?



#20 lazypineapple

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Posted 03 January 2019 - 09:49 AM

Hmmm.... I am very tempted to try this.  There are many of these camera right angle finders on e-bay, new and used.  Does alignment of the right angle finder with the polar scope need to be precise?

Not precise just, in front of the hole. The one I got has a X3 magnifier switch works great for my Old Eyes. The units are pretty cheap.  Amazon  too. 

If that holder only was available would be nice. 

Or if you have access to a 3d printer make a holder. 

All I could find was a pill bottle. 



#21 lazypineapple

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Posted 03 January 2019 - 09:53 AM

 
Magnifier X3.2
 
IMG 2981

 



#22 orlyandico

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Posted 03 January 2019 - 02:04 PM

Doesn't this assume that the OTA is coaxial with the RA axis? that is not necessarily the case...

 

Also.. I 3d-printed an adapter for the common $20 Contax RA camera finder on ebay - https://www.cloudyni...or-polar-scope/

 

 

There are three methods. All three require a crosshair eyepiece: 

 

1: Use the setting circles on the mount to aim at the position of Polaris (or any other star!!) and center it in the crosshair eyepiece. This method requires you to first align the setting circles. 

 

2: Use the setting circles to aim the scope at exactly 90° DEC (RA doesn't matter) and then aim directly at the celestial pole among the stars. An accurate map of the region is needed. If you use a diagonal on the scope, you need a mirror-reversed map that matches the view in the diagonal. 

 

3: This method can be used on any mount, also those without setting circles. First aim the scope at roughly 90° DEC and with the scope "on top" of the mount (counterweight shaft vertical), first align the horizontal crosshair with the pole; then turn the mount 90° in RA, so that the scope sits to one side of the mount and align the vertical crosshair with the pole. Repeat the process if necessary. By turning the mount 180°, you can check for parallax errors in the mount. 

 

 

It was CN member Daquad that made me aware of method #2 and #3. I'm using #2 myself and it really is crazy accurate, considering how simple it is. You can very easily get polar aligned to an accuracy of a couple of arc minutes in just a few minutes, once you get familiar with the process. All this at the convenience of the big, bright and comfortable view in your main scope. The scope shouldn't be too big, though, lest the field of view becomes too narrow. 

 

 

Clear skies!
Thomas, Denmark



#23 Astrojensen

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Posted 03 January 2019 - 02:54 PM

Doesn't this assume that the OTA is coaxial with the RA axis? that is not necessarily the case...

Not for methods #1 and #3, but it assumes low orthogonality errors in the mount and between the mount and scope. 

 

 

Clear skies!
Thomas, Denmark 



#24 25585

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Posted 03 January 2019 - 06:27 PM

I must stress that you DO NOT aim at Polaris with method #2 and #3, but at the true celestial pole, and that in order to use method #1, your setting circles must already be aligned. You do not need a star to align the setting circles, only an accurate spirit level. 

 

 

Clear skies!
Thomas, Denmark

Polaris is near enough the celestial pole to set up for visual tracking as the pole where corrections can be made while viewing.



#25 Astrojensen

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Posted 03 January 2019 - 06:34 PM

Polaris is near enough the celestial pole to set up for visual tracking as the pole where corrections can be made while viewing.

Oh, absolutely! Most of the time I just eyeball it over the mount and that is just fine for visual. 

 

But if you use the main scope and a crosshair eyepiece, you can get a polar alignment to within one or two arc minutes in just a few more minutes, good enough for accurate setting circle work or astrophotography. 

 

 

Clear skies!
Thomas, Denmark


Edited by Astrojensen, 03 January 2019 - 06:34 PM.



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