Hi Dennis
I have used mounts with Polar Alignment Scopes (PAS) with the Octans "trapezium" shaped reticule, one with a field of view of 6 degrees and another with a FOV of 3 degrees and agree - in can be tough! In my back garden I have marked 3 spots where I place my tripod so I can find the Octans stars (Sigma Octans) very easily now.
Here’s how I would start off at an astro camp or new location:
Use a magnetic compass to locate magnetic South.
Now we know that magnetic South and True South as defined by the South Celestial Pole (SCP) are not the same.
- Magnetic South is where the compass needle points.
- True South and the SCP is the point around which the skies appear to revolve (the projection of the Earth’s axis of rotation onto the imaginary celestial sphere).
For Brisbane, the SCP is now some 10 or 11 degrees E of magnetic South. So, when we look south and have our compass needle pointing to magnetic South, the True South (SCP) is some 10 degrees to the East (or our left as we look south).
My tripod has a peg on the tripod head which sits over a leg and I set this leg and peg to point True South. I then fit my German Equatorial Mount onto the tripod and using a template that fits on the declination shaft, I adjust the altitude screw on the mount until I am at 27.5 degrees for Brisbane.
The template is a triangular piece of 12mm plywood with the long side of the triangle making an angle of 27.5 degrees to the next longest side. I place the long side against the Dec shaft then place a bubble level on the short side of the triangle and adjust the altitude screw on the mount until the bubble is level. I then know that the Dec axis is at 27.5 degrees even if the tripod head is not level.
Using these techniques, I can usually get with 2 or 3 degrees of the SCP and then locate Sigma Octans in the PAS. Hope I haven’t bamboozled you! If so, ask away and I’ll try again.
Cheers
Dennis