Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Super Polaris Mount - polar alignment process?

  • Please log in to reply
10 replies to this topic

#1 Blueox4

Blueox4

    Messenger

  • *****
  • topic starter
  • Posts: 442
  • Joined: 26 Nov 2015
  • Loc: Upstate New York

Posted 17 September 2019 - 01:43 PM

I’ve got a nice Super Polaris Mount that I’m trying to learn how to use the polar alignment scope and paragraph 5 in the manual I don’t understand. Excuse my ignorance but how does one find the Standard Meridian for my time zone and do the instructions mean subtract my actual longitude from the referenced standard meridian and what would be the starting point on the scale? Does anyone know how to make this simpler to understand? Just paragraph 5 I don’t get. Here’s a couple pics. I’m just trying to learn to use this old Mount with the slow motion controls.  Thank you!

Attached Thumbnails

  • 6AA359A0-A74E-47C8-A9C7-C11F1245D446.jpeg
  • A9C1BC2C-4CDF-4E12-A0C1-E05271A93465.jpeg
  • 9433EA86-FC3F-4C16-8301-4E9F8F85E743.jpeg

  • miniqtone likes this

#2 miniqtone

miniqtone

    Vostok 1

  • *****
  • Posts: 180
  • Joined: 28 Oct 2014
  • Loc: Central NC

Posted 17 September 2019 - 02:11 PM

I’ve got a nice Super Polaris Mount that I’m trying to learn how to use the polar alignment scope and paragraph 5 in the manual I don’t understand. Excuse my ignorance but how does one find the Standard Meridian for my time zone and do the instructions mean subtract my actual longitude from the referenced standard meridian and what would be the starting point on the scale? Does anyone know how to make this simpler to understand? Just paragraph 5 I don’t get. Here’s a couple pics. I’m just trying to learn to use this old Mount with the slow motion controls.  Thank you!

If you wish to track the sky via the slow motion controls only, for visual use all you have to do is

1) Level the tripod

2) Center Polaris in the pole scope.

 

This should be plenty good enough for your purposes



#3 Der_Pit

Der_Pit

    Viking 1

  • -----
  • Posts: 840
  • Joined: 07 Jul 2018
  • Loc: La Palma

Posted 17 September 2019 - 02:13 PM

The standard meridian is the longitude referring to your local time zone.  E.g., if your time is UTC−05:00 this would be latitude 75 degrees west.  One hour corresponds to 15 degrees.  If your real latitude (where you and your mount are) is 79.5 West that would be a meridian offset of 4.5 degrees.  So you dial that in on the small scale, then just follow the instructions (match date and time on the two scales, put zero on top, then get Polaris to the location on the reticle.  

I find the method extremely accurate, with my GP-DX I got a alignment error in low arcmin range before the sky was really dark enough to use plate solving solutions....


  • miniqtone and Blueox4 like this

#4 Blueox4

Blueox4

    Messenger

  • *****
  • topic starter
  • Posts: 442
  • Joined: 26 Nov 2015
  • Loc: Upstate New York

Posted 17 September 2019 - 02:41 PM

If you wish to track the sky via the slow motion controls only, for visual use all you have to do is

1) Level the tripod

2) Center Polaris in the pole scope.

 

This should be plenty good enough for your purposes

Thank you! That works for sure but looking to understand why the instructions are as they are for using the Polar scope. 


  • miniqtone likes this

#5 miniqtone

miniqtone

    Vostok 1

  • *****
  • Posts: 180
  • Joined: 28 Oct 2014
  • Loc: Central NC

Posted 17 September 2019 - 03:31 PM

Thank you! That works for sure but looking to understand why the instructions are as they are for using the Polar scope. 

I don't blame you for wanting to understand the instructions, because when/if you use the mount with a drive at high magnifications, or for AP, dialing-in the polar alignment will be a good thing to do! smile.gif

 

I understand that your Super Polaris is a good solid mount and I look forward to owning one someday. Enjoy it!


Edited by miniqtone, 17 September 2019 - 03:31 PM.

  • Blueox4 likes this

#6 Sammy

Sammy

    Sputnik

  • *****
  • Posts: 40
  • Joined: 19 Jun 2009
  • Loc: Virginia

Posted 17 September 2019 - 05:18 PM

Did you remove the polar scope?

#7 Blueox4

Blueox4

    Messenger

  • *****
  • topic starter
  • Posts: 442
  • Joined: 26 Nov 2015
  • Loc: Upstate New York

Posted 17 September 2019 - 05:28 PM

Did you remove the polar scope?

I just unscrewed it from the mounting hole yes.



#8 Sammy

Sammy

    Sputnik

  • *****
  • Posts: 40
  • Joined: 19 Jun 2009
  • Loc: Virginia

Posted 17 September 2019 - 05:45 PM

You may need to realign it now

#9 Stephen Kennedy

Stephen Kennedy

    Surveyor 1

  • *****
  • Posts: 1833
  • Joined: 03 Jul 2014
  • Loc: California

Posted 17 September 2019 - 06:55 PM

If your Vixen Super Polaris GEM is as old as mine (purchased new in 1988) the polar scope reticle can no longer be used for extremely precise polar alignment such as you would need if you put an RA motor on it and used it for AP.  The reason is the precession of the Earth's rotational axis.  Although the period is 26,000 years, such high precision is needed for AP that the passage of 30 years will render the polar scope unable to be used.  If you are just going to stick with the slow motion controls, which are very good on the SP, just putting Polaris in the center of the FOV of the polar scope will suffice.



#10 telesonic

telesonic

    Ranger 4

  • *****
  • Posts: 312
  • Joined: 17 Oct 2016
  • Loc: SW Idaho - USA

Posted 17 September 2019 - 11:51 PM

As mentioned, centering Polaris in the polar scope will work fine for visual work, and that's pretty much what I've mostly done on my SP since I've had it - and it's close enough for low f/l tracking if you have an RA drive.

 

 

However....  if you want to delve into even deeper waters:

 

Here is a link to Vixen / Company Seven (.PDF) file that better explains the Time Zone and Meridian offset calculation.
(this is for the GP - but still applicable)

 

http://www.company7....eZoneOffset.pdf


Now you can just use Google Earth to get the local Longitude closest to your observing place, with the above and some math.... it's pretty easy to figure out from there. Make sure that you align the polar scope to the mounts RA axis the best that you can. Also - don't trust the the little tiny bubble level on these classic mounts, (or any mount for that matter) verify it's level with a good one if you have it handy. I have two SP heads here and both spirit levels were off by quite a bit, so check 'em.

 

 

 

Regarding the reticle - it is indeed outdated, but if you want to tackle it - (a small project) one can get a newer version:

Around a year ago I purchased a used SP complete with a polar scope, and I contacted a rep from Vixen USA about this very thing. I was able to purchase an updated glass reticle (by itself) for a GP unit  - as I was told it's the same as the SP. Fits fine, and seems to give a much better polar alignment than the old one. YMMV.
I set this one up with the counterweight bar parked down, and the reticle aligned to that for the upper culmination of Polaris.... and just use an app on my phone for a quick align for the angle of the dangle.

 

Here is a shot of the replacement reticle when I was sighting it all on a utility pole.

 

 

 

Vixen SP polar finder replacement reticle test
 
 
While the SP is now long out of production.... it's a very Classic medium capacity mount for the era - and I personally feel that is still a very useable mount today if one can be found in decent condition. As always, YMMV.
 
Best,
T

Edited by telesonic, 17 September 2019 - 11:53 PM.

  • Stephen Kennedy likes this

#11 dpaigen

dpaigen

    Sputnik

  • -----
  • Posts: 49
  • Joined: 30 Jul 2019

Posted 18 September 2019 - 09:40 AM

I have an old SP that I am considering re-purposing for wide field AP (100-300mm).  I will need to add motors; I see there are still SS2000 kits available but at $1000 that seems excessive.  I suspect I can source stepper motors, brackets, couplers, electronics, and a raspberry for under $100.  $200 max.  But that is a long term project.  At the moment I have my hands full trying to get round stars in my images.  :-)

 

Clear skies,

-David




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics