Page 1 of 9 123 ... LastLast
Results 1 to 10 of 88
Like Tree3Likes

Thread: Polar Alignment in Australia Southern Hemisphere

  1. #1
    admin's Avatar
    admin is offline Administrator
    Points: 6,989,798, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 5.0%
    Achievements:
    First 1000 Experience PointsGot three Friends20+ Friends Achievement!5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Mar 2007
    Location
    Sydney, Australia
    Posts
    13,470
    Points
    6,989,798
    Level
    100
    Thanks
    18,563
    Thanked 7,912x 3,807 Posts
    Blog Entries
    2

    Question Polar Alignment in Australia Southern Hemisphere



    Hi guys,
    wanted to know how you experts polar align in the Southern Hemisphere and Australia.

    thanks
    Name: Gus OTAs: ED 100 PRO refractor, Orion ST80 (not the CF), 8" Dob stuck in Canada Mounts:HEQ5PRO Synscan mount, Manfrotto Tripod CAMS: Guidecam Philips SPC900 webcams (4), Canon unmodded-450D DSLR

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    |
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    | My Astronomy Blog

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


  2. The Following User Says Thank You to admin For This Useful Post:

    alfaisalll (09-02-2011)

  3. #2
    Carlos_dfc's Avatar
    Carlos_dfc is offline Moderator
    Points: 17,230, Level: 90
    Level completed: 80%, Points required for next Level: 70
    Overall activity: 0%
    Achievements:
    Got three Friends20+ Friends Achievement!First 1000 Experience Points100+ Threads Achievement!365 Days+ Registered Achievement!
    Join Date
    Jun 2008
    Location
    near Darlington UK
    Posts
    1,760
    Points
    17,230
    Level
    90
    Thanks
    141
    Thanked 1,414x 703 Posts

    Default

    There are a few stars which are quite near to the South Celestial Pole.

    Polaris is about 3/4 of a degree away from the North Pole - In the Southern hemisphere, Sigma Octans is only about a degree and a bit, away from the South Pole.
    Biggest difference is that Polaris is quite a prominent naked-eye star (mag 2) - whereas Sigma Octans is only 5th magnitude.

    In the South, you need to learn roughly where Sigma Octans is, and the area around it - so you can find it in a scope or finderscope - then from there, find the 7th magnitude star, 37 Octans.
    37 Octans is less than quarter of a degree away from the South celestial pole - so if you learn how to find that - it is a more accurate marker than Polaris is in the North.

    If you can find 'Achernar' in Eridanus, and 'Acrux' in the Southern Cross.
    The mid-point between those stars will put you in the right 'ball-park' area.
    Last edited by Carlos_dfc; 10-17-2008 at 03:59 PM.
    Moderator

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    Co-Founder: Bishop Auckland Astronomical Society
    Co-Presenter: Monthly "What's up in the Sky" programme - BISHOP FM radio

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  4. The Following 2 Users Say Thank You to Carlos_dfc For This Useful Post:

    admin (01-14-2009),FlyingBeagles (03-05-2017)

  5. #3
    Vinnie's Avatar
    Vinnie is offline Guest
    Points: 24,260, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    Got three Friends20+ Friends Achievement!First 1000 Experience Points5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Sep 2008
    Location
    Queensland, Australia
    Posts
    3,474
    Points
    24,260
    Level
    100
    Thanks
    41
    Thanked 682x 362 Posts

    Default

    Hi guys,

    Polar alignment without Polaris is an interesting topic.

    As Carlos has said, there are means to do this in the South,from the sky, and there certainly are dual reticle polar scopes that include the Southern Hemisphere. I have two, but to be honest I have never used them (they shipped with the mounts concerned).

    Omega Octans is the Southern Pole Star, but at Mag 15 isn't much use. In general, I don't find Octans very helpfull as even Sigma is a bit dim when viewed through a small low mag unit such as a PS or finder.

    Overall for a rough alignment, using the "guestimate" with Crux and Rigel Kent and Hadar works, but I generally use a magnetic compass for a bit better accuracy, and for quite a neat alignment I have made up a couple of jigs that incorporate a mag compass and an engineer's protractor that get very close to the mark at any time, day or night.

    Unfortunately I am not home at the moment, and won't be for about 10 days, so I only have the grab n go small scopes with me and I don't have the jigs.

    When I get home I will post some photos and a brief tutorial, you'll have to wait till then LOL

  6. The Following 3 Users Say Thank You to Vinnie For This Useful Post:

    admin (02-10-2009),alfaisalll (09-02-2011),FlyingBeagles (03-05-2017)

  7. #4
    admin's Avatar
    admin is offline Administrator
    Points: 6,989,798, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 5.0%
    Achievements:
    First 1000 Experience PointsGot three Friends20+ Friends Achievement!5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Mar 2007
    Location
    Sydney, Australia
    Posts
    13,470
    Points
    6,989,798
    Level
    100
    Thanks
    18,563
    Thanked 7,912x 3,807 Posts
    Blog Entries
    2

    Default

    awesome thanks i will be working on alignment as well I will post my pics / videos and findings soon
    Name: Gus OTAs: ED 100 PRO refractor, Orion ST80 (not the CF), 8" Dob stuck in Canada Mounts:HEQ5PRO Synscan mount, Manfrotto Tripod CAMS: Guidecam Philips SPC900 webcams (4), Canon unmodded-450D DSLR

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    |
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    | My Astronomy Blog

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


  8. #5
    Vinnie's Avatar
    Vinnie is offline Guest
    Points: 24,260, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    Got three Friends20+ Friends Achievement!First 1000 Experience Points5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Sep 2008
    Location
    Queensland, Australia
    Posts
    3,474
    Points
    24,260
    Level
    100
    Thanks
    41
    Thanked 682x 362 Posts

    Default

    OK Admin, I'm home and got my stuff together.

    The question is how to Polar align without Polaris, which could apply to either hemisphere, and also if you want to align during daylight. Don't forget that there is one star that many of us observe during daylight, its called the Sun LOL. Also I find it convenient to set up before sunset in most cases.

    You will need a Sylva style orienteering compass, although I suggest that there are cheaper brands than Sylva which work just fine. Also a home made tool or two, a small spirit level and you will need to know your latitude, and current magnetic variation.

    In the first two photos you will see an aluminium bar that is drilled and tapped to meet the tripod assembly's azimuth pin, and the central mount head locating bolt. There is a scribed central line which is aligned to the compass's lubber line. Here at this time the mag variation is 10.25 degrees East, so true south is at 170 degrees magnetic (close enough, a quarter of a degree is neither here nor there)

    You could make a similar bar from wood, but obviously not steel.

    When I say within a rounded half degree is close enough, I mean that that is fine for visual or short exposure photos, or for setting up a GoTo. If you are into long exposure photography, drift alignment is the only way to go, and that is an entirely different ball game.

    So screw on the bar, roughly level the setup by eye, sit the compass over the central line with it set to show true South, or North as the case may be, and rotate the whole tripod until you have it point to True South (or North).

    I kid you not, this step takes about one minute




  9. The Following 9 Users Say Thank You to Vinnie For This Useful Post:

    admin (01-14-2009),alfaisalll (09-02-2011),Brian bee (01-04-2010),drafrete (07-14-2011),Frankus (03-06-2015),jjacer (01-02-2012),mckechg (03-11-2013),peterb666 (05-28-2014),SteveZA (06-05-2012)

  10. #6
    Vinnie's Avatar
    Vinnie is offline Guest
    Points: 24,260, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    Got three Friends20+ Friends Achievement!First 1000 Experience Points5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Sep 2008
    Location
    Queensland, Australia
    Posts
    3,474
    Points
    24,260
    Level
    100
    Thanks
    41
    Thanked 682x 362 Posts

    Default

    Step two:

    Remove the bar and accurately level the tripod head. Some mounts have no bubble, most have a fiddly little thing that you can hardly see. In this photo I am using a cut down old level, but a pocket level is only a few dollars. Make sure to move the level over three positions, ie over each tripod leg.

    Again, this takes about a minute. Two minutes so far, OK

    Last edited by Vinnie; 10-31-2008 at 10:04 AM.

  11. The Following 5 Users Say Thank You to Vinnie For This Useful Post:

    alfaisalll (09-02-2011),Frankus (03-06-2015),mckechg (03-11-2013),Startup (12-22-2012),SteveZA (06-05-2012)

  12. #7
    Vinnie's Avatar
    Vinnie is offline Guest
    Points: 24,260, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    Got three Friends20+ Friends Achievement!First 1000 Experience Points5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Sep 2008
    Location
    Queensland, Australia
    Posts
    3,474
    Points
    24,260
    Level
    100
    Thanks
    41
    Thanked 682x 362 Posts

    Default

    Step 3

    Set your Latitude

    You can do this from the Latitude scale on your mount head right?

    Wrong!

    Surprisingly, even on many more expensive and larger mounts this scale is woefully inaccurate, and difficult to read even if it is actually accurate.

    In the photos here, this HEQ5 is out by 3 degrees.

    So attach your mount head. This is important: make sure that the head is central over the Azimuth pin, or you've got this far for nothing. This is easy to judge by ensuring that the Azimuth adjusting screws are equal on both sides, I do this by eye, if it worries you, use a small ruler.

    Now set the mount head in the "home" position. ie Dec 90 and CW shaft vertical.

    In the first photo I am (well actually SWMBO is) using an engineers protractor over the mount's receiver. I have one because it is a stock tool in my trade, and is accurate to less than half a degree. You can by a cheapie for maybe $30 or $40. These protractors have a bubble in them. But you don't need one of these if you don't want to spend the money.

    The second photo shows a $2 plastic protractor with a plumb line attached, held against the CW shaft. I have deliberately fitted a string thicker than you would use for accuracy, as a thin one wouldn't show in the photo. This is also accurate to at least half a degree.

    Another minute of time? Three minutes so far and you are now polar aligned to about a half of a degree accuracy. If you are unsure and trying this for the first time, even if it took 10 minutes, you are still up and running. Also remember that a polar scope is only as accurate as the Date settings on its setting circles, and these are generally not accurate enough to get you down to half a degree.

    Finally, if you really need more accuracy, you will need to drift align, and that is a story for another day that is better explained on video tutorials on several websites, better than I can do with words and photos




  13. The Following 10 Users Say Thank You to Vinnie For This Useful Post:

    alfaisalll (09-02-2011),Frankus (03-06-2015),IanWhite (12-28-2011),jjacer (01-02-2012),mckechg (03-25-2013),Miguell (01-17-2013),seefer (06-27-2010),Startup (12-22-2012),SteveZA (06-05-2012),Tapguy (12-30-2012)

  14. #8
    Vinnie's Avatar
    Vinnie is offline Guest
    Points: 24,260, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    Got three Friends20+ Friends Achievement!First 1000 Experience Points5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Sep 2008
    Location
    Queensland, Australia
    Posts
    3,474
    Points
    24,260
    Level
    100
    Thanks
    41
    Thanked 682x 362 Posts

    Default

    Also for a quick rough and ready polar alignment here is a link, although I find my way doesn't take much longer and is much more accurate

    http://www.myastroshop.com.au/guides...lign-basic.pdf

  15. The Following 2 Users Say Thank You to Vinnie For This Useful Post:

    Frankus (03-06-2015),mckechg (03-25-2013)

  16. #9
    admin's Avatar
    admin is offline Administrator
    Points: 6,989,798, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 5.0%
    Achievements:
    First 1000 Experience PointsGot three Friends20+ Friends Achievement!5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Mar 2007
    Location
    Sydney, Australia
    Posts
    13,470
    Points
    6,989,798
    Level
    100
    Thanks
    18,563
    Thanked 7,912x 3,807 Posts
    Blog Entries
    2

    Default

    thank you Vinnie, looks like I have to buy a few more things but as long as I get the Goto working accurately I don't mind

    Any idea where to buy the compass or a cheap engineers protractor? I have a outdoor store next to me so I can get the compass there but I have no idea where to get the engineers protractor. Also will need to drill that wood/metal piece together.
    Name: Gus OTAs: ED 100 PRO refractor, Orion ST80 (not the CF), 8" Dob stuck in Canada Mounts:HEQ5PRO Synscan mount, Manfrotto Tripod CAMS: Guidecam Philips SPC900 webcams (4), Canon unmodded-450D DSLR

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    |
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    | My Astronomy Blog

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


  17. The Following User Says Thank You to admin For This Useful Post:

    alfaisalll (09-02-2011)

  18. #10
    Vinnie's Avatar
    Vinnie is offline Guest
    Points: 24,260, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    Got three Friends20+ Friends Achievement!First 1000 Experience Points5+ Referrals Achievement!100+ Threads Achievement!
    Join Date
    Sep 2008
    Location
    Queensland, Australia
    Posts
    3,474
    Points
    24,260
    Level
    100
    Thanks
    41
    Thanked 682x 362 Posts

    Default

    If you want to pay the postage I'll make you up a kit, you'll only need a compass. Give me a couple of days, I have a couple of other jobs for another guy's scope first, and I want to fit a new focuser on one of mine

 

 
Page 1 of 9 123 ... LastLast

Similar Threads

  1. Northern Vs Southern Hemisphere.
    By interstellaryeller in forum Off Topic Forum
    Replies: 9
    Last Post: 04-18-2010, 05:52 PM
  2. Hi From the southern hemisphere
    By Tyler222 in forum Forum Welcomes Introductions
    Replies: 6
    Last Post: 04-17-2010, 08:37 PM
  3. Why McNaught only in the southern hemisphere now
    By Jack Pansprout in forum Amateur Astronomy Forum
    Replies: 8
    Last Post: 01-17-2007, 09:09 PM
  4. Northern And Southern Hemisphere.
    By Matalog in forum Amateur Astronomy Forum
    Replies: 4
    Last Post: 03-14-2006, 03:58 PM
  5. Northern Hemisphere or Southern Hemisphere?
    By Matalog in forum Amateur Astronomy Forum
    Replies: 1
    Last Post: 03-13-2006, 10:32 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 02:32 AM.