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Anonymous
Unregistered
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At home, where I do all of my star gazing I have no view of Polaris due to a bunch of very large fir trees in my way So I have always set up my scope (ETX-125) In Alt/Az Mode. I have been doing more astrophotography and know that polar mode is essential if you want to get any decent shots. After thinking about it for quite a while I figured out a way to do it and it worked perfectly for me on the first night.
Here is what I did; I am lucky in that my scope, if aliened properly, will be dead on any target I go to I set my scope up like I always had (in Alt/Az mode) and did a two star alignment. Then I did a test run and told it to go to Vega, as usual, dead on. Then I told it to go to Polaris and of course it landed about 20 feet up an a trunk of a 150 foot tree. I got out my laser level and painted that exact spot. I then set up my scope in polar mode, aimed it at that spot then slightly offset it in the direction of Kochab (I’ve been told that Polaris is not dead on true north). I did my alignment and set my sights on M-13, after 3 hours M-13 was still dead center!
So, Did I get lucky or did I find a way to get around “line of sight? I’m going to try again tonight and I will let you know.
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Anonymous
Unregistered
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I think you found a way.  If polaris is clouded up, but the rest of the sky is okay, i just point my mount north then do drift aligning. So there is more than one way to find polar north if you can't see it.
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Undermidnight
BEOTS "Tweener Cup" winner
Reged: 05/25/04
Posts: 3411
Loc: Hilliard, Ohio
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You did find a way. You do not have to "see" polaris to polar align. Just know where it is approximately (the closer you are to north the better of course!!) If you know where to align up your scope, and you do drift alignment like John mentioned, you will be polar aligned.
You are aligning to the pole. Polaris just "happens" to be close to the pole (It's a great signpost!!)
Good job!
Jason
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"There's only two things that excite a man, expensive toys and real expensive toys." - Red Green
WO Zenithstar 66 on Microstar Mount
8" Ultima 2000, "Wilma"
8" F/4.2 Ultralight, "Marilyn II"
12.5" F/4.3 Ultralight, "Ada II"
11x70 Oberwerks
6" F/6 Figuring
Pans, Orthos, and Naglers
"We who cut mere stones, must always be envisioning cathedrals." - The Quarry Workers Creed
http://www.undermidnight.com
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Anonymous
Unregistered
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Did it again last night, dead on! <pats self on back>
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LivingNDixie
TSP Chowhound
Reged: 04/23/03
Posts: 17757
Loc: Trussville, AL
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Very resourcefull...
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Preston
Meade 10in LX200R GPS UHTC
blog (updated 02/15/2013)
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Undermidnight
BEOTS "Tweener Cup" winner
Reged: 05/25/04
Posts: 3411
Loc: Hilliard, Ohio
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BTW... once you find the pole, you never have to readjust! The pole never moves.
Good job.
Jason
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"There's only two things that excite a man, expensive toys and real expensive toys." - Red Green
WO Zenithstar 66 on Microstar Mount
8" Ultima 2000, "Wilma"
8" F/4.2 Ultralight, "Marilyn II"
12.5" F/4.3 Ultralight, "Ada II"
11x70 Oberwerks
6" F/6 Figuring
Pans, Orthos, and Naglers
"We who cut mere stones, must always be envisioning cathedrals." - The Quarry Workers Creed
http://www.undermidnight.com
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cwstad
sage
Reged: 07/22/04
Posts: 305
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I use an alignmate. Very simple and very accurate and very inexpensive.
http://www.telescopehouse.co.uk/page.aspx?theLang=001lngdef&pointerid=50E5543C7F9E4E638B50E99AC713D909
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Celestron 80EQ
Meade ETX 125
Homepage http://www.farstar.co.uk
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BluewaterObserva
Postmaster
Reged: 05/18/04
Posts: 5748
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My friends that do astrophotography a lot, always amaze me, they actually never hit polaris it seems. They just put it on a star and observe the drift, and have enough experience to just move the mount / altitude based on the drift only...
I am not so talented by any means though. Cool ya got a way to do it!!!!
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DJMcCrady
Carpal Tunnel
Reged: 06/27/03
Posts: 1692
Loc: Seattle, WA
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Let me inject into this discussion how some mounts, specificially Losmandy Gemini-equipped mounts, have builtin features to make polar alignment a snap.
The Gemini system, in addition to being a very accurate GOTO system, has features that utilize its pointing model to aid in accurate polar alignment. Basically, after leveling the mount and doing several star-aligns, the mount can compute its deviation from true polar alignment. It can then use this information, and a feature called Polar Axis Correction, to guide altitude/azimuth adjustments that correct any polar axis misalignment.
You start by leveling the mount and doing a rough polar alignment. The polar alignment doesn't have to be perfect, but the closer you are to start with, the easier things are.
After building a pointing model, you GOTO a star near the intersection of the meridian and equator (i.e., due south and declination 0), and center it in the eyepiece. Polar axis correction will then slew away to the position that Gemini's model believe the star should be had the polar alignment been perfect. You then adjust altitude & azimuth until the star is centered again. Simple, and quite accurate. With an accurate reticle eyepiece, I can get within 1 or 2 arcminutes of the pole in about 20 minutes.
I'm sure other high-end mounts have similar features.
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++don;
http://starryvistas.net
Tak Sky 90, Tak EM200, STL-4020M
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Undermidnight
BEOTS "Tweener Cup" winner
Reged: 05/25/04
Posts: 3411
Loc: Hilliard, Ohio
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That is way cool! I also saw that my U2K has some features (although not intentional) where you use the warp factor to help assist you in hitting the pole.
Jason
--------------------
"There's only two things that excite a man, expensive toys and real expensive toys." - Red Green
WO Zenithstar 66 on Microstar Mount
8" Ultima 2000, "Wilma"
8" F/4.2 Ultralight, "Marilyn II"
12.5" F/4.3 Ultralight, "Ada II"
11x70 Oberwerks
6" F/6 Figuring
Pans, Orthos, and Naglers
"We who cut mere stones, must always be envisioning cathedrals." - The Quarry Workers Creed
http://www.undermidnight.com
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