Article: Polar Alignment with a Wedge in the Southern Hemisphere

[iceman]

Hi all

Chris James (cwjames) has written an article describing the process of Polar Alignment with a Wedge in the Southern Hemisphere.

You can read the article on the IceInSpace Projects & Articles (http://www.iceinspace.com.au/?projects) page, or directly by clicking on the link below:

Polar Alignment with a Wedge in the Southern Hemisphere (http://www.iceinspace.com.au/index.php?id=63,454,0,0,1,0)

Thanks to Chris for writing the article. If you'd like to submit an article or review to IceInSpace, please contact me (http://www.iceinspace.com.au/?contact).

[iceman]

Article uploaded.

[mdgodf]

I was looking for just this information the other day! Its a great article. Thanks to Chris for doing it.

A point of clarification though...when the scope is in polar home position the finder is on the bottom - is that right? When Autostar slews to Sigma Octanis and goes from 0h RA to 21h RA the finder ends up 'on top' so it's easier to sight through - is that right

[AndrewJ]

Gday Mark



For the LX200GPS/Rs, that is correct. It is done this way to ensure the scope starts midway between its hardstops.



Close... but no wabbit .
In home position, the scope is at 0h in HA(Hour Angle) NOT RA
RA changes constantly based on time
As such, you start at HA = 0 and based on date/time, the scope gets a rough idea of where RA is. It uses this to estimate where the target star is, and you confirm that when you align
As such, if you do a 1 star align ( where it slews to Sigma Octans first),
it will first slew from DEC = -90 to DEC = -88:57, then slew to the RA "wherever Sigma Octans is"
Ie SigOct may be below the pole, in which case the finder will be on top,
but if Sigma Octans is above the pole when you align, the finder will stay underneath ( and you need a rubber neck )

Andrew

[mdgodf]

Thanks Andrew, I think that's clearer now! I suspected I'd need a rubber neck!

[Ric]

Many thanks for the article Chris.

I have just purchased an Ultrawedge so I will be soon taking my first step into polar aligning.

Cheers